* [PATCH v2 01/11] virt: sev-guest: Use AES GCM crypto library
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 19:09 ` Tom Lendacky
2023-03-26 14:46 ` [PATCH v2 02/11] virt: sev-guest: Move mutex to SNP guest device structure Nikunj A Dadhania
` (9 subsequent siblings)
10 siblings, 1 reply; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
SEV-SNP guests with SecureTSC enabled need to send a TSC_INFO SNP
Guest message to the AMD security processor before the smpboot phase
starts. Details from the TSC_INFO response have to be programmed in
the VMSA before the secondary CPUs are brought up.
Start using the AES GCM library implementation as the crypto API is not
available yet this early.
Link: https://lore.kernel.org/all/20221103192259.2229-1-ardb@kernel.org
CC: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
drivers/virt/coco/sev-guest/Kconfig | 3 +-
drivers/virt/coco/sev-guest/sev-guest.c | 172 +++++++-----------------
drivers/virt/coco/sev-guest/sev-guest.h | 3 +
3 files changed, 53 insertions(+), 125 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig
index f9db0799ae67..bcc760bfb468 100644
--- a/drivers/virt/coco/sev-guest/Kconfig
+++ b/drivers/virt/coco/sev-guest/Kconfig
@@ -2,8 +2,7 @@ config SEV_GUEST
tristate "AMD SEV Guest driver"
default m
depends on AMD_MEM_ENCRYPT
- select CRYPTO_AEAD2
- select CRYPTO_GCM
+ select CRYPTO_LIB_AESGCM
help
SEV-SNP firmware provides the guest a mechanism to communicate with
the PSP without risk from a malicious hypervisor who wishes to read,
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 46f1a8d558b0..57af908bafba 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -16,8 +16,7 @@
#include <linux/miscdevice.h>
#include <linux/set_memory.h>
#include <linux/fs.h>
-#include <crypto/aead.h>
-#include <linux/scatterlist.h>
+#include <crypto/gcm.h>
#include <linux/psp-sev.h>
#include <uapi/linux/sev-guest.h>
#include <uapi/linux/psp-sev.h>
@@ -28,24 +27,16 @@
#include "sev-guest.h"
#define DEVICE_NAME "sev-guest"
-#define AAD_LEN 48
-#define MSG_HDR_VER 1
#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
#define SNP_REQ_RETRY_DELAY (2*HZ)
-struct snp_guest_crypto {
- struct crypto_aead *tfm;
- u8 *iv, *authtag;
- int iv_len, a_len;
-};
-
struct snp_guest_dev {
struct device *dev;
struct miscdevice misc;
void *certs_data;
- struct snp_guest_crypto *crypto;
+ struct aesgcm_ctx *ctx;
struct snp_guest_msg *request, *response;
struct snp_secrets_page_layout *layout;
struct snp_req_data input;
@@ -60,6 +51,15 @@ MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.
/* Mutex to serialize the shared buffer access and command handling. */
static DEFINE_MUTEX(snp_cmd_mutex);
+static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
+{
+ if (snp_dev && snp_dev->ctx)
+ return snp_dev->ctx->authsize;
+
+ WARN_ONCE(1, "Unable to get crypto authsize\n");
+ return 0;
+}
+
static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
{
char zero_key[VMPCK_KEY_LEN] = {0};
@@ -144,132 +144,59 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
return container_of(dev, struct snp_guest_dev, misc);
}
-static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen)
+static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
{
- struct snp_guest_crypto *crypto;
+ struct aesgcm_ctx *ctx;
- crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT);
- if (!crypto)
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+ if (!ctx)
return NULL;
- crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
- if (IS_ERR(crypto->tfm))
- goto e_free;
-
- if (crypto_aead_setkey(crypto->tfm, key, keylen))
- goto e_free_crypto;
-
- crypto->iv_len = crypto_aead_ivsize(crypto->tfm);
- crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT);
- if (!crypto->iv)
- goto e_free_crypto;
-
- if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) {
- if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) {
- dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN);
- goto e_free_iv;
- }
+ if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
+ pr_err("SNP: crypto init failed\n");
+ kfree(ctx);
+ return NULL;
}
- crypto->a_len = crypto_aead_authsize(crypto->tfm);
- crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT);
- if (!crypto->authtag)
- goto e_free_iv;
-
- return crypto;
-
-e_free_iv:
- kfree(crypto->iv);
-e_free_crypto:
- crypto_free_aead(crypto->tfm);
-e_free:
- kfree(crypto);
-
- return NULL;
+ return ctx;
}
-static void deinit_crypto(struct snp_guest_crypto *crypto)
-{
- crypto_free_aead(crypto->tfm);
- kfree(crypto->iv);
- kfree(crypto->authtag);
- kfree(crypto);
-}
-
-static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg,
- u8 *src_buf, u8 *dst_buf, size_t len, bool enc)
-{
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
- struct scatterlist src[3], dst[3];
- DECLARE_CRYPTO_WAIT(wait);
- struct aead_request *req;
- int ret;
-
- req = aead_request_alloc(crypto->tfm, GFP_KERNEL);
- if (!req)
- return -ENOMEM;
-
- /*
- * AEAD memory operations:
- * +------ AAD -------+------- DATA -----+---- AUTHTAG----+
- * | msg header | plaintext | hdr->authtag |
- * | bytes 30h - 5Fh | or | |
- * | | cipher | |
- * +------------------+------------------+----------------+
- */
- sg_init_table(src, 3);
- sg_set_buf(&src[0], &hdr->algo, AAD_LEN);
- sg_set_buf(&src[1], src_buf, hdr->msg_sz);
- sg_set_buf(&src[2], hdr->authtag, crypto->a_len);
-
- sg_init_table(dst, 3);
- sg_set_buf(&dst[0], &hdr->algo, AAD_LEN);
- sg_set_buf(&dst[1], dst_buf, hdr->msg_sz);
- sg_set_buf(&dst[2], hdr->authtag, crypto->a_len);
-
- aead_request_set_ad(req, AAD_LEN);
- aead_request_set_tfm(req, crypto->tfm);
- aead_request_set_callback(req, 0, crypto_req_done, &wait);
-
- aead_request_set_crypt(req, src, dst, len, crypto->iv);
- ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait);
-
- aead_request_free(req);
- return ret;
-}
-
-static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
+static int __enc_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
void *plaintext, size_t len)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_guest_msg_hdr *hdr = &msg->hdr;
+ u8 iv[GCM_AES_IV_SIZE] = {};
- memset(crypto->iv, 0, crypto->iv_len);
- memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ if (WARN_ON((hdr->msg_sz + ctx->authsize) > sizeof(msg->payload)))
+ return -EBADMSG;
- return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true);
+ memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ aesgcm_encrypt(ctx, msg->payload, plaintext, len, &hdr->algo, AAD_LEN,
+ iv, hdr->authtag);
+ return 0;
}
-static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
+static int dec_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
void *plaintext, size_t len)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_guest_msg_hdr *hdr = &msg->hdr;
+ u8 iv[GCM_AES_IV_SIZE] = {};
- /* Build IV with response buffer sequence number */
- memset(crypto->iv, 0, crypto->iv_len);
- memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
-
- return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false);
+ memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ if (aesgcm_decrypt(ctx, plaintext, msg->payload, len, &hdr->algo,
+ AAD_LEN, iv, hdr->authtag))
+ return 0;
+ else
+ return -EBADMSG;
}
static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_guest_msg *resp = snp_dev->response;
struct snp_guest_msg *req = snp_dev->request;
struct snp_guest_msg_hdr *req_hdr = &req->hdr;
struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+ struct aesgcm_ctx *ctx = snp_dev->ctx;
dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
@@ -287,11 +214,11 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
* If the message size is greater than our buffer length then return
* an error.
*/
- if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
+ if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
return -EBADMSG;
/* Decrypt the payload */
- return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
+ return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
}
static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
@@ -318,7 +245,7 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
- return __enc_payload(snp_dev, req, payload, sz);
+ return __enc_payload(snp_dev->ctx, req, payload, sz);
}
static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
@@ -446,7 +373,6 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_report_resp *resp;
struct snp_report_req req;
int rc, resp_len;
@@ -464,7 +390,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + crypto->a_len;
+ resp_len = sizeof(resp->data) + get_ctx_authsize(snp_dev);
resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
if (!resp)
return -ENOMEM;
@@ -485,7 +411,6 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_derived_key_resp resp = {0};
struct snp_derived_key_req req;
int rc, resp_len;
@@ -502,7 +427,7 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp.data) + crypto->a_len;
+ resp_len = sizeof(resp.data) + get_ctx_authsize(snp_dev);
if (sizeof(buf) < resp_len)
return -ENOMEM;
@@ -527,7 +452,6 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
- struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_ext_report_req req;
struct snp_report_resp *resp;
int ret, npages = 0, resp_len;
@@ -565,7 +489,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
* response payload. Make sure that it has enough space to cover the
* authtag.
*/
- resp_len = sizeof(resp->data) + crypto->a_len;
+ resp_len = sizeof(resp->data) + get_ctx_authsize(snp_dev);
resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
if (!resp)
return -ENOMEM;
@@ -777,8 +701,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_free_response;
ret = -EIO;
- snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
- if (!snp_dev->crypto)
+ snp_dev->ctx = snp_init_crypto(snp_dev->vmpck, VMPCK_KEY_LEN);
+ if (!snp_dev->ctx)
goto e_free_cert_data;
misc = &snp_dev->misc;
@@ -793,11 +717,13 @@ static int __init sev_guest_probe(struct platform_device *pdev)
ret = misc_register(misc);
if (ret)
- goto e_free_cert_data;
+ goto e_free_ctx;
dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
return 0;
+e_free_ctx:
+ kfree(snp_dev->ctx);
e_free_cert_data:
free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
e_free_response:
@@ -816,7 +742,7 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
- deinit_crypto(snp_dev->crypto);
+ kfree(snp_dev->ctx);
misc_deregister(&snp_dev->misc);
return 0;
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h
index 21bda26fdb95..ceb798a404d6 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ b/drivers/virt/coco/sev-guest/sev-guest.h
@@ -13,6 +13,9 @@
#include <linux/types.h>
#define MAX_AUTHTAG_LEN 32
+#define AUTHTAG_LEN 16
+#define AAD_LEN 48
+#define MSG_HDR_VER 1
/* See SNP spec SNP_GUEST_REQUEST section for the structure */
enum msg_type {
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 01/11] virt: sev-guest: Use AES GCM crypto library
2023-03-26 14:46 ` [PATCH v2 01/11] virt: sev-guest: Use AES GCM crypto library Nikunj A Dadhania
@ 2023-04-03 19:09 ` Tom Lendacky
2023-04-05 5:10 ` Nikunj A. Dadhania
0 siblings, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 19:09 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> SEV-SNP guests with SecureTSC enabled need to send a TSC_INFO SNP
> Guest message to the AMD security processor before the smpboot phase
> starts. Details from the TSC_INFO response have to be programmed in
> the VMSA before the secondary CPUs are brought up.
>
> Start using the AES GCM library implementation as the crypto API is not
> available yet this early.
This isn't quite true, yet. You should add that the encryption code will
be moved out of sev-guest to support Secure TSC, but to make the diffs
easier to review, convert the Crypto API usage over to AES GCM library
usage before moving it.
Thanks,
Tom
>
> Link: https://lore.kernel.org/all/20221103192259.2229-1-ardb@kernel.org
> CC: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> drivers/virt/coco/sev-guest/Kconfig | 3 +-
> drivers/virt/coco/sev-guest/sev-guest.c | 172 +++++++-----------------
> drivers/virt/coco/sev-guest/sev-guest.h | 3 +
> 3 files changed, 53 insertions(+), 125 deletions(-)
>
> diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig
> index f9db0799ae67..bcc760bfb468 100644
> --- a/drivers/virt/coco/sev-guest/Kconfig
> +++ b/drivers/virt/coco/sev-guest/Kconfig
> @@ -2,8 +2,7 @@ config SEV_GUEST
> tristate "AMD SEV Guest driver"
> default m
> depends on AMD_MEM_ENCRYPT
> - select CRYPTO_AEAD2
> - select CRYPTO_GCM
> + select CRYPTO_LIB_AESGCM
> help
> SEV-SNP firmware provides the guest a mechanism to communicate with
> the PSP without risk from a malicious hypervisor who wishes to read,
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index 46f1a8d558b0..57af908bafba 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -16,8 +16,7 @@
> #include <linux/miscdevice.h>
> #include <linux/set_memory.h>
> #include <linux/fs.h>
> -#include <crypto/aead.h>
> -#include <linux/scatterlist.h>
> +#include <crypto/gcm.h>
> #include <linux/psp-sev.h>
> #include <uapi/linux/sev-guest.h>
> #include <uapi/linux/psp-sev.h>
> @@ -28,24 +27,16 @@
> #include "sev-guest.h"
>
> #define DEVICE_NAME "sev-guest"
> -#define AAD_LEN 48
> -#define MSG_HDR_VER 1
>
> #define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
> #define SNP_REQ_RETRY_DELAY (2*HZ)
>
> -struct snp_guest_crypto {
> - struct crypto_aead *tfm;
> - u8 *iv, *authtag;
> - int iv_len, a_len;
> -};
> -
> struct snp_guest_dev {
> struct device *dev;
> struct miscdevice misc;
>
> void *certs_data;
> - struct snp_guest_crypto *crypto;
> + struct aesgcm_ctx *ctx;
> struct snp_guest_msg *request, *response;
> struct snp_secrets_page_layout *layout;
> struct snp_req_data input;
> @@ -60,6 +51,15 @@ MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.
> /* Mutex to serialize the shared buffer access and command handling. */
> static DEFINE_MUTEX(snp_cmd_mutex);
>
> +static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
> +{
> + if (snp_dev && snp_dev->ctx)
> + return snp_dev->ctx->authsize;
> +
> + WARN_ONCE(1, "Unable to get crypto authsize\n");
> + return 0;
> +}
> +
> static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
> {
> char zero_key[VMPCK_KEY_LEN] = {0};
> @@ -144,132 +144,59 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
> return container_of(dev, struct snp_guest_dev, misc);
> }
>
> -static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen)
> +static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
> {
> - struct snp_guest_crypto *crypto;
> + struct aesgcm_ctx *ctx;
>
> - crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT);
> - if (!crypto)
> + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
> + if (!ctx)
> return NULL;
>
> - crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
> - if (IS_ERR(crypto->tfm))
> - goto e_free;
> -
> - if (crypto_aead_setkey(crypto->tfm, key, keylen))
> - goto e_free_crypto;
> -
> - crypto->iv_len = crypto_aead_ivsize(crypto->tfm);
> - crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT);
> - if (!crypto->iv)
> - goto e_free_crypto;
> -
> - if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) {
> - if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) {
> - dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN);
> - goto e_free_iv;
> - }
> + if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
> + pr_err("SNP: crypto init failed\n");
> + kfree(ctx);
> + return NULL;
> }
>
> - crypto->a_len = crypto_aead_authsize(crypto->tfm);
> - crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT);
> - if (!crypto->authtag)
> - goto e_free_iv;
> -
> - return crypto;
> -
> -e_free_iv:
> - kfree(crypto->iv);
> -e_free_crypto:
> - crypto_free_aead(crypto->tfm);
> -e_free:
> - kfree(crypto);
> -
> - return NULL;
> + return ctx;
> }
>
> -static void deinit_crypto(struct snp_guest_crypto *crypto)
> -{
> - crypto_free_aead(crypto->tfm);
> - kfree(crypto->iv);
> - kfree(crypto->authtag);
> - kfree(crypto);
> -}
> -
> -static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg,
> - u8 *src_buf, u8 *dst_buf, size_t len, bool enc)
> -{
> - struct snp_guest_msg_hdr *hdr = &msg->hdr;
> - struct scatterlist src[3], dst[3];
> - DECLARE_CRYPTO_WAIT(wait);
> - struct aead_request *req;
> - int ret;
> -
> - req = aead_request_alloc(crypto->tfm, GFP_KERNEL);
> - if (!req)
> - return -ENOMEM;
> -
> - /*
> - * AEAD memory operations:
> - * +------ AAD -------+------- DATA -----+---- AUTHTAG----+
> - * | msg header | plaintext | hdr->authtag |
> - * | bytes 30h - 5Fh | or | |
> - * | | cipher | |
> - * +------------------+------------------+----------------+
> - */
> - sg_init_table(src, 3);
> - sg_set_buf(&src[0], &hdr->algo, AAD_LEN);
> - sg_set_buf(&src[1], src_buf, hdr->msg_sz);
> - sg_set_buf(&src[2], hdr->authtag, crypto->a_len);
> -
> - sg_init_table(dst, 3);
> - sg_set_buf(&dst[0], &hdr->algo, AAD_LEN);
> - sg_set_buf(&dst[1], dst_buf, hdr->msg_sz);
> - sg_set_buf(&dst[2], hdr->authtag, crypto->a_len);
> -
> - aead_request_set_ad(req, AAD_LEN);
> - aead_request_set_tfm(req, crypto->tfm);
> - aead_request_set_callback(req, 0, crypto_req_done, &wait);
> -
> - aead_request_set_crypt(req, src, dst, len, crypto->iv);
> - ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait);
> -
> - aead_request_free(req);
> - return ret;
> -}
> -
> -static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
> +static int __enc_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
> void *plaintext, size_t len)
> {
> - struct snp_guest_crypto *crypto = snp_dev->crypto;
> struct snp_guest_msg_hdr *hdr = &msg->hdr;
> + u8 iv[GCM_AES_IV_SIZE] = {};
>
> - memset(crypto->iv, 0, crypto->iv_len);
> - memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> + if (WARN_ON((hdr->msg_sz + ctx->authsize) > sizeof(msg->payload)))
> + return -EBADMSG;
>
> - return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true);
> + memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> + aesgcm_encrypt(ctx, msg->payload, plaintext, len, &hdr->algo, AAD_LEN,
> + iv, hdr->authtag);
> + return 0;
> }
>
> -static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
> +static int dec_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
> void *plaintext, size_t len)
> {
> - struct snp_guest_crypto *crypto = snp_dev->crypto;
> struct snp_guest_msg_hdr *hdr = &msg->hdr;
> + u8 iv[GCM_AES_IV_SIZE] = {};
>
> - /* Build IV with response buffer sequence number */
> - memset(crypto->iv, 0, crypto->iv_len);
> - memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> -
> - return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false);
> + memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> + if (aesgcm_decrypt(ctx, plaintext, msg->payload, len, &hdr->algo,
> + AAD_LEN, iv, hdr->authtag))
> + return 0;
> + else
> + return -EBADMSG;
> }
>
> static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
> {
> - struct snp_guest_crypto *crypto = snp_dev->crypto;
> struct snp_guest_msg *resp = snp_dev->response;
> struct snp_guest_msg *req = snp_dev->request;
> struct snp_guest_msg_hdr *req_hdr = &req->hdr;
> struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
> + struct aesgcm_ctx *ctx = snp_dev->ctx;
>
> dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
> resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
> @@ -287,11 +214,11 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
> * If the message size is greater than our buffer length then return
> * an error.
> */
> - if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz))
> + if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
> return -EBADMSG;
>
> /* Decrypt the payload */
> - return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len);
> + return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
> }
>
> static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
> @@ -318,7 +245,7 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
> dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
> hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
>
> - return __enc_payload(snp_dev, req, payload, sz);
> + return __enc_payload(snp_dev->ctx, req, payload, sz);
> }
>
> static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
> @@ -446,7 +373,6 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
>
> static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> {
> - struct snp_guest_crypto *crypto = snp_dev->crypto;
> struct snp_report_resp *resp;
> struct snp_report_req req;
> int rc, resp_len;
> @@ -464,7 +390,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
> * response payload. Make sure that it has enough space to cover the
> * authtag.
> */
> - resp_len = sizeof(resp->data) + crypto->a_len;
> + resp_len = sizeof(resp->data) + get_ctx_authsize(snp_dev);
> resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
> if (!resp)
> return -ENOMEM;
> @@ -485,7 +411,6 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
>
> static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> {
> - struct snp_guest_crypto *crypto = snp_dev->crypto;
> struct snp_derived_key_resp resp = {0};
> struct snp_derived_key_req req;
> int rc, resp_len;
> @@ -502,7 +427,7 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
> * response payload. Make sure that it has enough space to cover the
> * authtag.
> */
> - resp_len = sizeof(resp.data) + crypto->a_len;
> + resp_len = sizeof(resp.data) + get_ctx_authsize(snp_dev);
> if (sizeof(buf) < resp_len)
> return -ENOMEM;
>
> @@ -527,7 +452,6 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
>
> static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> {
> - struct snp_guest_crypto *crypto = snp_dev->crypto;
> struct snp_ext_report_req req;
> struct snp_report_resp *resp;
> int ret, npages = 0, resp_len;
> @@ -565,7 +489,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
> * response payload. Make sure that it has enough space to cover the
> * authtag.
> */
> - resp_len = sizeof(resp->data) + crypto->a_len;
> + resp_len = sizeof(resp->data) + get_ctx_authsize(snp_dev);
> resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT);
> if (!resp)
> return -ENOMEM;
> @@ -777,8 +701,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> goto e_free_response;
>
> ret = -EIO;
> - snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN);
> - if (!snp_dev->crypto)
> + snp_dev->ctx = snp_init_crypto(snp_dev->vmpck, VMPCK_KEY_LEN);
> + if (!snp_dev->ctx)
> goto e_free_cert_data;
>
> misc = &snp_dev->misc;
> @@ -793,11 +717,13 @@ static int __init sev_guest_probe(struct platform_device *pdev)
>
> ret = misc_register(misc);
> if (ret)
> - goto e_free_cert_data;
> + goto e_free_ctx;
>
> dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
> return 0;
>
> +e_free_ctx:
> + kfree(snp_dev->ctx);
> e_free_cert_data:
> free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
> e_free_response:
> @@ -816,7 +742,7 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
> free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
> free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> - deinit_crypto(snp_dev->crypto);
> + kfree(snp_dev->ctx);
> misc_deregister(&snp_dev->misc);
>
> return 0;
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h
> index 21bda26fdb95..ceb798a404d6 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.h
> +++ b/drivers/virt/coco/sev-guest/sev-guest.h
> @@ -13,6 +13,9 @@
> #include <linux/types.h>
>
> #define MAX_AUTHTAG_LEN 32
> +#define AUTHTAG_LEN 16
> +#define AAD_LEN 48
> +#define MSG_HDR_VER 1
>
> /* See SNP spec SNP_GUEST_REQUEST section for the structure */
> enum msg_type {
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 01/11] virt: sev-guest: Use AES GCM crypto library
2023-04-03 19:09 ` Tom Lendacky
@ 2023-04-05 5:10 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 5:10 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 12:39 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> SEV-SNP guests with SecureTSC enabled need to send a TSC_INFO SNP
>> Guest message to the AMD security processor before the smpboot phase
>> starts. Details from the TSC_INFO response have to be programmed in
>> the VMSA before the secondary CPUs are brought up.
>>
>> Start using the AES GCM library implementation as the crypto API is not
>> available yet this early.
>
> This isn't quite true, yet. You should add that the encryption code will
> be moved out of sev-guest to support Secure TSC, but to make the diffs> easier to review, convert the Crypto API usage over to AES GCM library > usage before moving it.
Yes, will change it accordingly.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 02/11] virt: sev-guest: Move mutex to SNP guest device structure
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
2023-03-26 14:46 ` [PATCH v2 01/11] virt: sev-guest: Use AES GCM crypto library Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 19:13 ` Tom Lendacky
2023-03-26 14:46 ` [PATCH v2 03/11] virt: sev-guest: Add snp_guest_req structure Nikunj A Dadhania
` (8 subsequent siblings)
10 siblings, 1 reply; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
In preparation to provide new API for sending SNP guest message to the
sev-guest driver, move the SNP command mutex to the snp_guest_dev
structure.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
drivers/virt/coco/sev-guest/sev-guest.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 57af908bafba..6ae197b57644 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -35,6 +35,9 @@ struct snp_guest_dev {
struct device *dev;
struct miscdevice misc;
+ /* Mutex to serialize the shared buffer access and command handling. */
+ struct mutex cmd_mutex;
+
void *certs_data;
struct aesgcm_ctx *ctx;
struct snp_guest_msg *request, *response;
@@ -48,9 +51,6 @@ static u32 vmpck_id;
module_param(vmpck_id, uint, 0444);
MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
-/* Mutex to serialize the shared buffer access and command handling. */
-static DEFINE_MUTEX(snp_cmd_mutex);
-
static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
{
if (snp_dev && snp_dev->ctx)
@@ -99,7 +99,7 @@ static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
{
u64 count;
- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);
/* Read the current message sequence counter from secrets pages */
count = *snp_dev->os_area_msg_seqno;
@@ -377,7 +377,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
struct snp_report_req req;
int rc, resp_len;
- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -417,7 +417,7 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
/* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
u8 buf[64 + 16];
- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -456,7 +456,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
struct snp_report_resp *resp;
int ret, npages = 0, resp_len;
- lockdep_assert_held(&snp_cmd_mutex);
+ lockdep_assert_held(&snp_dev->cmd_mutex);
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -541,12 +541,12 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
if (!input.msg_version)
return -EINVAL;
- mutex_lock(&snp_cmd_mutex);
+ mutex_lock(&snp_dev->cmd_mutex);
/* Check if the VMPCK is not empty */
if (is_vmpck_empty(snp_dev)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
- mutex_unlock(&snp_cmd_mutex);
+ mutex_unlock(&snp_dev->cmd_mutex);
return -ENOTTY;
}
@@ -564,7 +564,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
break;
}
- mutex_unlock(&snp_cmd_mutex);
+ mutex_unlock(&snp_dev->cmd_mutex);
if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
return -EFAULT;
@@ -683,6 +683,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_unmap;
}
+ mutex_init(&snp_dev->cmd_mutex);
platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
snp_dev->layout = layout;
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 02/11] virt: sev-guest: Move mutex to SNP guest device structure
2023-03-26 14:46 ` [PATCH v2 02/11] virt: sev-guest: Move mutex to SNP guest device structure Nikunj A Dadhania
@ 2023-04-03 19:13 ` Tom Lendacky
2023-04-05 5:23 ` Nikunj A. Dadhania
0 siblings, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 19:13 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> In preparation to provide new API for sending SNP guest message to the
> sev-guest driver, move the SNP command mutex to the snp_guest_dev
> structure.
In preparation for providing a new API to the sev-guest driver for sending
an SNP guest message, ...
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> drivers/virt/coco/sev-guest/sev-guest.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index 57af908bafba..6ae197b57644 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -35,6 +35,9 @@ struct snp_guest_dev {
> struct device *dev;
> struct miscdevice misc;
>
> + /* Mutex to serialize the shared buffer access and command handling. */
> + struct mutex cmd_mutex;
> +
> void *certs_data;
> struct aesgcm_ctx *ctx;
> struct snp_guest_msg *request, *response;
> @@ -48,9 +51,6 @@ static u32 vmpck_id;
> module_param(vmpck_id, uint, 0444);
> MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
>
> -/* Mutex to serialize the shared buffer access and command handling. */
> -static DEFINE_MUTEX(snp_cmd_mutex);
> -
> static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
> {
> if (snp_dev && snp_dev->ctx)
> @@ -99,7 +99,7 @@ static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> {
> u64 count;
>
> - lockdep_assert_held(&snp_cmd_mutex);
> + lockdep_assert_held(&snp_dev->cmd_mutex);
>
> /* Read the current message sequence counter from secrets pages */
> count = *snp_dev->os_area_msg_seqno;
> @@ -377,7 +377,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
> struct snp_report_req req;
> int rc, resp_len;
>
> - lockdep_assert_held(&snp_cmd_mutex);
> + lockdep_assert_held(&snp_dev->cmd_mutex);
>
> if (!arg->req_data || !arg->resp_data)
> return -EINVAL;
> @@ -417,7 +417,7 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
> /* Response data is 64 bytes and max authsize for GCM is 16 bytes. */
> u8 buf[64 + 16];
>
> - lockdep_assert_held(&snp_cmd_mutex);
> + lockdep_assert_held(&snp_dev->cmd_mutex);
>
> if (!arg->req_data || !arg->resp_data)
> return -EINVAL;
> @@ -456,7 +456,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
> struct snp_report_resp *resp;
> int ret, npages = 0, resp_len;
>
> - lockdep_assert_held(&snp_cmd_mutex);
> + lockdep_assert_held(&snp_dev->cmd_mutex);
>
> if (!arg->req_data || !arg->resp_data)
> return -EINVAL;
> @@ -541,12 +541,12 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
> if (!input.msg_version)
> return -EINVAL;
>
> - mutex_lock(&snp_cmd_mutex);
> + mutex_lock(&snp_dev->cmd_mutex);
>
> /* Check if the VMPCK is not empty */
> if (is_vmpck_empty(snp_dev)) {
> dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
> - mutex_unlock(&snp_cmd_mutex);
> + mutex_unlock(&snp_dev->cmd_mutex);
> return -ENOTTY;
> }
>
> @@ -564,7 +564,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
> break;
> }
>
> - mutex_unlock(&snp_cmd_mutex);
> + mutex_unlock(&snp_dev->cmd_mutex);
>
> if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
> return -EFAULT;
> @@ -683,6 +683,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> goto e_unmap;
> }
>
> + mutex_init(&snp_dev->cmd_mutex);
> platform_set_drvdata(pdev, snp_dev);
> snp_dev->dev = dev;
> snp_dev->layout = layout;
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 02/11] virt: sev-guest: Move mutex to SNP guest device structure
2023-04-03 19:13 ` Tom Lendacky
@ 2023-04-05 5:23 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 5:23 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 12:43 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> In preparation to provide new API for sending SNP guest message to the
>> sev-guest driver, move the SNP command mutex to the snp_guest_dev
>> structure.
>
> In preparation for providing a new API to the sev-guest driver for sending an SNP guest message, ...
Sure.
>>
>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
>
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 03/11] virt: sev-guest: Add snp_guest_req structure
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
2023-03-26 14:46 ` [PATCH v2 01/11] virt: sev-guest: Use AES GCM crypto library Nikunj A Dadhania
2023-03-26 14:46 ` [PATCH v2 02/11] virt: sev-guest: Move mutex to SNP guest device structure Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 19:59 ` Tom Lendacky
2023-03-26 14:46 ` [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck Nikunj A Dadhania
` (7 subsequent siblings)
10 siblings, 1 reply; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
Add a snp_guest_req structure to simplify the function arguments. The
structure will be used to call the SNP Guest message request API
instead of passing a long list of parameters.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
drivers/virt/coco/sev-guest/sev-guest.c | 87 ++++++++++++++-----------
drivers/virt/coco/sev-guest/sev-guest.h | 19 ++++++
2 files changed, 68 insertions(+), 38 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 6ae197b57644..ec93dee330f2 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -60,16 +60,6 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
return 0;
}
-static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
-{
- char zero_key[VMPCK_KEY_LEN] = {0};
-
- if (snp_dev->vmpck)
- return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN);
-
- return true;
-}
-
/*
* If an error is received from the host or AMD Secure Processor (ASP) there
* are two options. Either retry the exact same encrypted request or discontinue
@@ -198,8 +188,9 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
struct aesgcm_ctx *ctx = snp_dev->ctx;
- dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
- resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
+ pr_debug("response [seqno %lld type %d version %d sz %d]\n",
+ resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
+ resp_hdr->msg_sz);
/* Verify that the sequence counter is incremented by 1 */
if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
@@ -221,34 +212,34 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
}
-static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
- void *payload, size_t sz)
+static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno,
+ struct snp_guest_req *req, u8 __vmpck_id)
{
- struct snp_guest_msg *req = snp_dev->request;
- struct snp_guest_msg_hdr *hdr = &req->hdr;
+ struct snp_guest_msg *msg = snp_dev->request;
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
- memset(req, 0, sizeof(*req));
+ memset(msg, 0, sizeof(*msg));
hdr->algo = SNP_AEAD_AES_256_GCM;
hdr->hdr_version = MSG_HDR_VER;
hdr->hdr_sz = sizeof(*hdr);
- hdr->msg_type = type;
- hdr->msg_version = version;
+ hdr->msg_type = req->msg_type;
+ hdr->msg_version = req->msg_version;
hdr->msg_seqno = seqno;
- hdr->msg_vmpck = vmpck_id;
- hdr->msg_sz = sz;
+ hdr->msg_vmpck = __vmpck_id;
+ hdr->msg_sz = req->req_sz;
/* Verify the sequence number is non-zero */
if (!hdr->msg_seqno)
return -ENOSR;
- dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
+ pr_debug("request [seqno %lld type %d version %d sz %d]\n",
hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
- return __enc_payload(snp_dev->ctx, req, payload, sz);
+ return __enc_payload(snp_dev->ctx, msg, req->req_buf, req->req_sz);
}
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
{
unsigned long err = 0xff, override_err = 0;
unsigned long req_start = jiffies;
@@ -262,7 +253,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* sequence number must be incremented or the VMPCK must be deleted to
* prevent reuse of the IV.
*/
- rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
+ rc = snp_issue_guest_request(req->exit_code, &snp_dev->input, &err);
switch (rc) {
case -ENOSPC:
/*
@@ -273,7 +264,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
* IV reuse.
*/
override_npages = snp_dev->input.data_npages;
- exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
/*
* Override the error to inform callers the given extended
@@ -314,8 +305,8 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
*/
snp_inc_msg_seqno(snp_dev);
- if (fw_err)
- *fw_err = override_err ?: err;
+ if (req->fw_err)
+ *req->fw_err = override_err ?: err;
if (override_npages)
snp_dev->input.data_npages = override_npages;
@@ -332,13 +323,14 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
return rc;
}
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
- u8 type, void *req_buf, size_t req_sz, void *resp_buf,
- u32 resp_sz, __u64 *fw_err)
+static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
{
u64 seqno;
int rc;
+ if (!snp_dev || !req)
+ return -ENODEV;
+
/* Get message sequence and verify that its a non-zero */
seqno = snp_get_msg_seqno(snp_dev);
if (!seqno)
@@ -347,21 +339,22 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
/* Encrypt the userspace provided payload */
- rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
+ rc = enc_payload(snp_dev, seqno, req, vmpck_id);
if (rc)
return rc;
- rc = __handle_guest_request(snp_dev, exit_code, fw_err);
+ rc = __handle_guest_request(snp_dev, req);
if (rc) {
- if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN)
+ if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
return rc;
- dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", rc, *fw_err);
+ dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n",
+ rc, *req->fw_err);
snp_disable_vmpck(snp_dev);
return rc;
}
- rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
+ rc = verify_and_dec_payload(snp_dev, req->resp_buf, req->resp_sz);
if (rc) {
dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
snp_disable_vmpck(snp_dev);
@@ -371,6 +364,24 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
return 0;
}
+
+static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
+ u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
+ u32 resp_sz, __u64 *fw_err)
+{
+ struct snp_guest_req guest_req = {
+ .msg_version = msg_version,
+ .msg_type = msg_type,
+ .req_buf = req_buf,
+ .req_sz = req_sz,
+ .resp_buf = resp_buf,
+ .resp_sz = resp_sz,
+ .fw_err = fw_err,
+ .exit_code = exit_code,
+ };
+ return snp_send_guest_request(snp_dev, &guest_req);
+}
+
static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
struct snp_report_resp *resp;
@@ -544,7 +555,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
mutex_lock(&snp_dev->cmd_mutex);
/* Check if the VMPCK is not empty */
- if (is_vmpck_empty(snp_dev)) {
+ if (is_vmpck_empty(snp_dev->vmpck)) {
dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
mutex_unlock(&snp_dev->cmd_mutex);
return -ENOTTY;
@@ -678,7 +689,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
}
/* Verify that VMPCK is not zero. */
- if (is_vmpck_empty(snp_dev)) {
+ if (is_vmpck_empty(snp_dev->vmpck)) {
dev_err(dev, "vmpck id %d is null\n", vmpck_id);
goto e_unmap;
}
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h
index ceb798a404d6..d245578d988e 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ b/drivers/virt/coco/sev-guest/sev-guest.h
@@ -63,4 +63,23 @@ struct snp_guest_msg {
u8 payload[4000];
} __packed;
+struct snp_guest_req {
+ void *req_buf, *resp_buf;
+ size_t req_sz, resp_sz;
+ u64 exit_code;
+ u64 *fw_err;
+ u8 msg_version;
+ u8 msg_type;
+};
+
+static inline bool is_vmpck_empty(u8 *vmpck)
+{
+ char zero_key[VMPCK_KEY_LEN] = {0};
+
+ if (vmpck)
+ return !memcmp(vmpck, zero_key, VMPCK_KEY_LEN);
+
+ return true;
+}
+
#endif /* __VIRT_SEVGUEST_H__ */
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 03/11] virt: sev-guest: Add snp_guest_req structure
2023-03-26 14:46 ` [PATCH v2 03/11] virt: sev-guest: Add snp_guest_req structure Nikunj A Dadhania
@ 2023-04-03 19:59 ` Tom Lendacky
2023-04-05 5:31 ` Nikunj A. Dadhania
0 siblings, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 19:59 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> Add a snp_guest_req structure to simplify the function arguments. The
> structure will be used to call the SNP Guest message request API
> instead of passing a long list of parameters.
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> drivers/virt/coco/sev-guest/sev-guest.c | 87 ++++++++++++++-----------
> drivers/virt/coco/sev-guest/sev-guest.h | 19 ++++++
> 2 files changed, 68 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index 6ae197b57644..ec93dee330f2 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -60,16 +60,6 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
> return 0;
> }
>
> -static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
> -{
> - char zero_key[VMPCK_KEY_LEN] = {0};
> -
> - if (snp_dev->vmpck)
> - return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN);
> -
> - return true;
> -}
> -
This change seems separate from the changes for snp_guest_req.
> /*
> * If an error is received from the host or AMD Secure Processor (ASP) there
> * are two options. Either retry the exact same encrypted request or discontinue
> @@ -198,8 +188,9 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
> struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
> struct aesgcm_ctx *ctx = snp_dev->ctx;
>
> - dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
> - resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
> + pr_debug("response [seqno %lld type %d version %d sz %d]\n",
> + resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
> + resp_hdr->msg_sz);
Again, not related to the purpose of this patch.
>
> /* Verify that the sequence counter is incremented by 1 */
> if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
> @@ -221,34 +212,34 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
> return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
> }
>
> -static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
> - void *payload, size_t sz)
> +static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno,
> + struct snp_guest_req *req, u8 __vmpck_id)
Can the vmpck_id be part of the snp_guest_req structure?
> {
> - struct snp_guest_msg *req = snp_dev->request;
> - struct snp_guest_msg_hdr *hdr = &req->hdr;
> + struct snp_guest_msg *msg = snp_dev->request;
> + struct snp_guest_msg_hdr *hdr = &msg->hdr;
>
> - memset(req, 0, sizeof(*req));
> + memset(msg, 0, sizeof(*msg));
>
> hdr->algo = SNP_AEAD_AES_256_GCM;
> hdr->hdr_version = MSG_HDR_VER;
> hdr->hdr_sz = sizeof(*hdr);
> - hdr->msg_type = type;
> - hdr->msg_version = version;
> + hdr->msg_type = req->msg_type;
> + hdr->msg_version = req->msg_version;
> hdr->msg_seqno = seqno;
> - hdr->msg_vmpck = vmpck_id;
> - hdr->msg_sz = sz;
> + hdr->msg_vmpck = __vmpck_id;
> + hdr->msg_sz = req->req_sz;
>
> /* Verify the sequence number is non-zero */
> if (!hdr->msg_seqno)
> return -ENOSR;
>
> - dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
> + pr_debug("request [seqno %lld type %d version %d sz %d]\n",
Unrelated change.
> hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
>
> - return __enc_payload(snp_dev->ctx, req, payload, sz);
> + return __enc_payload(snp_dev->ctx, msg, req->req_buf, req->req_sz);
> }
>
> -static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
> +static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
> {
> unsigned long err = 0xff, override_err = 0;
> unsigned long req_start = jiffies;
> @@ -262,7 +253,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
> * sequence number must be incremented or the VMPCK must be deleted to
> * prevent reuse of the IV.
> */
> - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
> + rc = snp_issue_guest_request(req->exit_code, &snp_dev->input, &err);
> switch (rc) {
> case -ENOSPC:
> /*
> @@ -273,7 +264,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
> * IV reuse.
> */
> override_npages = snp_dev->input.data_npages;
> - exit_code = SVM_VMGEXIT_GUEST_REQUEST;
> + req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
>
> /*
> * Override the error to inform callers the given extended
> @@ -314,8 +305,8 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
> */
> snp_inc_msg_seqno(snp_dev);
>
> - if (fw_err)
> - *fw_err = override_err ?: err;
> + if (req->fw_err)
> + *req->fw_err = override_err ?: err;
>
> if (override_npages)
> snp_dev->input.data_npages = override_npages;
> @@ -332,13 +323,14 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
> return rc;
> }
>
> -static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
> - u8 type, void *req_buf, size_t req_sz, void *resp_buf,
> - u32 resp_sz, __u64 *fw_err)
> +static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
> {
> u64 seqno;
> int rc;
>
> + if (!snp_dev || !req)
> + return -ENODEV;
This seems unrelated, at least the check for snp_dev. And looking at the
only caller, a guest request is always provided. So this seems unnecessary
- at least at this point in the series.
> +
> /* Get message sequence and verify that its a non-zero */
> seqno = snp_get_msg_seqno(snp_dev);
> if (!seqno)
> @@ -347,21 +339,22 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
> memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
>
> /* Encrypt the userspace provided payload */
> - rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
> + rc = enc_payload(snp_dev, seqno, req, vmpck_id);
> if (rc)
> return rc;
>
> - rc = __handle_guest_request(snp_dev, exit_code, fw_err);
> + rc = __handle_guest_request(snp_dev, req);
> if (rc) {
> - if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN)
> + if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
> return rc;
>
> - dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", rc, *fw_err);
> + dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n",
> + rc, *req->fw_err);
> snp_disable_vmpck(snp_dev);
> return rc;
> }
>
> - rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
> + rc = verify_and_dec_payload(snp_dev, req->resp_buf, req->resp_sz);
Can't you just pass req here?
> if (rc) {
> dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
> snp_disable_vmpck(snp_dev);
> @@ -371,6 +364,24 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
> return 0;
> }
>
> +
> +static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
> + u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
> + u32 resp_sz, __u64 *fw_err)
> +{
> + struct snp_guest_req guest_req = {
> + .msg_version = msg_version,
> + .msg_type = msg_type,
> + .req_buf = req_buf,
> + .req_sz = req_sz,
> + .resp_buf = resp_buf,
> + .resp_sz = resp_sz,
> + .fw_err = fw_err,
> + .exit_code = exit_code,
> + };
Add a blank line here.
Thanks,
Tom
> + return snp_send_guest_request(snp_dev, &guest_req);
> +}
> +
> static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> {
> struct snp_report_resp *resp;
> @@ -544,7 +555,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
> mutex_lock(&snp_dev->cmd_mutex);
>
> /* Check if the VMPCK is not empty */
> - if (is_vmpck_empty(snp_dev)) {
> + if (is_vmpck_empty(snp_dev->vmpck)) {
> dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n");
> mutex_unlock(&snp_dev->cmd_mutex);
> return -ENOTTY;
> @@ -678,7 +689,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> }
>
> /* Verify that VMPCK is not zero. */
> - if (is_vmpck_empty(snp_dev)) {
> + if (is_vmpck_empty(snp_dev->vmpck)) {
> dev_err(dev, "vmpck id %d is null\n", vmpck_id);
> goto e_unmap;
> }
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h
> index ceb798a404d6..d245578d988e 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.h
> +++ b/drivers/virt/coco/sev-guest/sev-guest.h
> @@ -63,4 +63,23 @@ struct snp_guest_msg {
> u8 payload[4000];
> } __packed;
>
> +struct snp_guest_req {
> + void *req_buf, *resp_buf;
> + size_t req_sz, resp_sz;
> + u64 exit_code;
> + u64 *fw_err;
> + u8 msg_version;
> + u8 msg_type;
> +};
> +
> +static inline bool is_vmpck_empty(u8 *vmpck)
> +{
> + char zero_key[VMPCK_KEY_LEN] = {0};
> +
> + if (vmpck)
> + return !memcmp(vmpck, zero_key, VMPCK_KEY_LEN);
> +
> + return true;
> +}
> +
> #endif /* __VIRT_SEVGUEST_H__ */
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 03/11] virt: sev-guest: Add snp_guest_req structure
2023-04-03 19:59 ` Tom Lendacky
@ 2023-04-05 5:31 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 5:31 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 1:29 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> Add a snp_guest_req structure to simplify the function arguments. The
>> structure will be used to call the SNP Guest message request API
>> instead of passing a long list of parameters.
>>
>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>> ---
>> drivers/virt/coco/sev-guest/sev-guest.c | 87 ++++++++++++++-----------
>> drivers/virt/coco/sev-guest/sev-guest.h | 19 ++++++
>> 2 files changed, 68 insertions(+), 38 deletions(-)
>>
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
>> index 6ae197b57644..ec93dee330f2 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.c
>> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
>> @@ -60,16 +60,6 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
>> return 0;
>> }
>> -static bool is_vmpck_empty(struct snp_guest_dev *snp_dev)
>> -{
>> - char zero_key[VMPCK_KEY_LEN] = {0};
>> -
>> - if (snp_dev->vmpck)
>> - return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN);
>> -
>> - return true;
>> -}
>> -
>
> This change seems separate from the changes for snp_guest_req.
Sure, will create a separate patch.
>
>> /*
>> * If an error is received from the host or AMD Secure Processor (ASP) there
>> * are two options. Either retry the exact same encrypted request or discontinue
>> @@ -198,8 +188,9 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
>> struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
>> struct aesgcm_ctx *ctx = snp_dev->ctx;
>> - dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
>> - resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
>> + pr_debug("response [seqno %lld type %d version %d sz %d]\n",
>> + resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
>> + resp_hdr->msg_sz);
>
> Again, not related to the purpose of this patch.
The idea was to get rid of dev_dbg for the movement, will do in a separate patch.
>
>> /* Verify that the sequence counter is incremented by 1 */
>> if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
>> @@ -221,34 +212,34 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
>> return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
>> }
>> -static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
>> - void *payload, size_t sz)
>> +static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno,
>> + struct snp_guest_req *req, u8 __vmpck_id)
>
> Can the vmpck_id be part of the snp_guest_req structure?
Sure, that should be possible.
>
>> {
>> - struct snp_guest_msg *req = snp_dev->request;
>> - struct snp_guest_msg_hdr *hdr = &req->hdr;
>> + struct snp_guest_msg *msg = snp_dev->request;
>> + struct snp_guest_msg_hdr *hdr = &msg->hdr;
>> - memset(req, 0, sizeof(*req));
>> + memset(msg, 0, sizeof(*msg));
>> hdr->algo = SNP_AEAD_AES_256_GCM;
>> hdr->hdr_version = MSG_HDR_VER;
>> hdr->hdr_sz = sizeof(*hdr);
>> - hdr->msg_type = type;
>> - hdr->msg_version = version;
>> + hdr->msg_type = req->msg_type;
>> + hdr->msg_version = req->msg_version;
>> hdr->msg_seqno = seqno;
>> - hdr->msg_vmpck = vmpck_id;
>> - hdr->msg_sz = sz;
>> + hdr->msg_vmpck = __vmpck_id;
>> + hdr->msg_sz = req->req_sz;
>> /* Verify the sequence number is non-zero */
>> if (!hdr->msg_seqno)
>> return -ENOSR;
>> - dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n",
>> + pr_debug("request [seqno %lld type %d version %d sz %d]\n",
>
> Unrelated change.
Will move to a separate patch.
>
>> hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
>> - return __enc_payload(snp_dev->ctx, req, payload, sz);
>> + return __enc_payload(snp_dev->ctx, msg, req->req_buf, req->req_sz);
>> }
>> -static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
>> +static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
>> {
>> unsigned long err = 0xff, override_err = 0;
>> unsigned long req_start = jiffies;
>> @@ -262,7 +253,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
>> * sequence number must be incremented or the VMPCK must be deleted to
>> * prevent reuse of the IV.
>> */
>> - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
>> + rc = snp_issue_guest_request(req->exit_code, &snp_dev->input, &err);
>> switch (rc) {
>> case -ENOSPC:
>> /*
>> @@ -273,7 +264,7 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
>> * IV reuse.
>> */
>> override_npages = snp_dev->input.data_npages;
>> - exit_code = SVM_VMGEXIT_GUEST_REQUEST;
>> + req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
>> /*
>> * Override the error to inform callers the given extended
>> @@ -314,8 +305,8 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
>> */
>> snp_inc_msg_seqno(snp_dev);
>> - if (fw_err)
>> - *fw_err = override_err ?: err;
>> + if (req->fw_err)
>> + *req->fw_err = override_err ?: err;
>> if (override_npages)
>> snp_dev->input.data_npages = override_npages;
>> @@ -332,13 +323,14 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
>> return rc;
>> }
>> -static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
>> - u8 type, void *req_buf, size_t req_sz, void *resp_buf,
>> - u32 resp_sz, __u64 *fw_err)
>> +static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
>> {
>> u64 seqno;
>> int rc;
>> + if (!snp_dev || !req)
>> + return -ENODEV;
>
> This seems unrelated, at least the check for snp_dev. And looking at the only caller, a guest request is always provided. So this seems unnecessary - at least at this point in the series.
Right, not necessary here, but will be needed when sev-guest driver calls this after the movement to sev.c. Otherwise, I will need to add this in the movement patch 5/11.
>
>> +
>> /* Get message sequence and verify that its a non-zero */
>> seqno = snp_get_msg_seqno(snp_dev);
>> if (!seqno)
>> @@ -347,21 +339,22 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
>> memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
>> /* Encrypt the userspace provided payload */
>> - rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
>> + rc = enc_payload(snp_dev, seqno, req, vmpck_id);
>> if (rc)
>> return rc;
>> - rc = __handle_guest_request(snp_dev, exit_code, fw_err);
>> + rc = __handle_guest_request(snp_dev, req);
>> if (rc) {
>> - if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN)
>> + if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
>> return rc;
>> - dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", rc, *fw_err);
>> + dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n",
>> + rc, *req->fw_err);
>> snp_disable_vmpck(snp_dev);
>> return rc;
>> }
>> - rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz);
>> + rc = verify_and_dec_payload(snp_dev, req->resp_buf, req->resp_sz);
>
> Can't you just pass req here?
Yes, can do that.
>
>> if (rc) {
>> dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
>> snp_disable_vmpck(snp_dev);
>> @@ -371,6 +364,24 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
>> return 0;
>> }
>> +
>> +static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
>> + u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
>> + u32 resp_sz, __u64 *fw_err)
>> +{
>> + struct snp_guest_req guest_req = {
>> + .msg_version = msg_version,
>> + .msg_type = msg_type,
>> + .req_buf = req_buf,
>> + .req_sz = req_sz,
>> + .resp_buf = resp_buf,
>> + .resp_sz = resp_sz,
>> + .fw_err = fw_err,
>> + .exit_code = exit_code,
>> + };
>
> Add a blank line here.
Sure.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (2 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 03/11] virt: sev-guest: Add snp_guest_req structure Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 20:26 ` Tom Lendacky
2023-04-10 16:31 ` Peter Gonda
2023-03-26 14:46 ` [PATCH v2 05/11] x86/sev: Move and reorganize sev guest request api Nikunj A Dadhania
` (6 subsequent siblings)
10 siblings, 2 replies; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
Simplify get_vmpck and prepare it to be used as an API. Update the
snp_guest_dev structure in snp_assign_vmpck(). Added vmpck_id to the
snp_guest_dev structure which can be used in SNP guest request API and
will remove direct use of vmpck_id command line parameter.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
drivers/virt/coco/sev-guest/sev-guest.c | 41 ++++++++-----------------
1 file changed, 12 insertions(+), 29 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index ec93dee330f2..4901ebc8fa1a 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -45,6 +45,7 @@ struct snp_guest_dev {
struct snp_req_data input;
u32 *os_area_msg_seqno;
u8 *vmpck;
+ u8 vmpck_id;
};
static u32 vmpck_id;
@@ -80,7 +81,7 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
{
dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
- vmpck_id);
+ snp_dev->vmpck_id);
memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
snp_dev->vmpck = NULL;
}
@@ -339,7 +340,7 @@ static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
/* Encrypt the userspace provided payload */
- rc = enc_payload(snp_dev, seqno, req, vmpck_id);
+ rc = enc_payload(snp_dev, seqno, req, snp_dev->vmpck_id);
if (rc)
return rc;
@@ -364,7 +365,6 @@ static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
return 0;
}
-
static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
u32 resp_sz, __u64 *fw_err)
@@ -625,32 +625,16 @@ static const struct file_operations snp_guest_fops = {
.unlocked_ioctl = snp_guest_ioctl,
};
-static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
+bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
{
- u8 *key = NULL;
+ if (WARN_ON(vmpck_id > 3))
+ return false;
- switch (id) {
- case 0:
- *seqno = &layout->os_area.msg_seqno_0;
- key = layout->vmpck0;
- break;
- case 1:
- *seqno = &layout->os_area.msg_seqno_1;
- key = layout->vmpck1;
- break;
- case 2:
- *seqno = &layout->os_area.msg_seqno_2;
- key = layout->vmpck2;
- break;
- case 3:
- *seqno = &layout->os_area.msg_seqno_3;
- key = layout->vmpck3;
- break;
- default:
- break;
- }
+ dev->vmpck_id = vmpck_id;
+ dev->vmpck = dev->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
+ dev->os_area_msg_seqno = &dev->layout->os_area.msg_seqno_0 + vmpck_id;
- return key;
+ return true;
}
static int __init sev_guest_probe(struct platform_device *pdev)
@@ -682,8 +666,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_unmap;
ret = -EINVAL;
- snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
- if (!snp_dev->vmpck) {
+ snp_dev->layout = layout;
+ if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
goto e_unmap;
}
@@ -697,7 +681,6 @@ static int __init sev_guest_probe(struct platform_device *pdev)
mutex_init(&snp_dev->cmd_mutex);
platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
- snp_dev->layout = layout;
/* Allocate the shared page used for the request and response message. */
snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck
2023-03-26 14:46 ` [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck Nikunj A Dadhania
@ 2023-04-03 20:26 ` Tom Lendacky
2023-04-05 6:18 ` Nikunj A. Dadhania
2023-04-10 16:31 ` Peter Gonda
1 sibling, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 20:26 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> Simplify get_vmpck and prepare it to be used as an API. Update the
> snp_guest_dev structure in snp_assign_vmpck(). Added vmpck_id to the
> snp_guest_dev structure which can be used in SNP guest request API and
> will remove direct use of vmpck_id command line parameter.
This needs to say more about why you're doing this. The first two
sentences need more explanation as they don't really stand on their own.
The last sentence talks about removing direct use of vmpck_id, so you
should probably do that in this patch since it seems to be the real reason
for all this.
Thanks,
Tom
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> drivers/virt/coco/sev-guest/sev-guest.c | 41 ++++++++-----------------
> 1 file changed, 12 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index ec93dee330f2..4901ebc8fa1a 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -45,6 +45,7 @@ struct snp_guest_dev {
> struct snp_req_data input;
> u32 *os_area_msg_seqno;
> u8 *vmpck;
> + u8 vmpck_id;
> };
>
> static u32 vmpck_id;
> @@ -80,7 +81,7 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
> static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
> {
> dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
> - vmpck_id);
> + snp_dev->vmpck_id);
> memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
> snp_dev->vmpck = NULL;
> }
> @@ -339,7 +340,7 @@ static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
> memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
>
> /* Encrypt the userspace provided payload */
> - rc = enc_payload(snp_dev, seqno, req, vmpck_id);
> + rc = enc_payload(snp_dev, seqno, req, snp_dev->vmpck_id);
> if (rc)
> return rc;
>
> @@ -364,7 +365,6 @@ static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
> return 0;
> }
>
> -
> static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
> u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
> u32 resp_sz, __u64 *fw_err)
> @@ -625,32 +625,16 @@ static const struct file_operations snp_guest_fops = {
> .unlocked_ioctl = snp_guest_ioctl,
> };
>
> -static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
> +bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
> {
> - u8 *key = NULL;
> + if (WARN_ON(vmpck_id > 3))
> + return false;
>
> - switch (id) {
> - case 0:
> - *seqno = &layout->os_area.msg_seqno_0;
> - key = layout->vmpck0;
> - break;
> - case 1:
> - *seqno = &layout->os_area.msg_seqno_1;
> - key = layout->vmpck1;
> - break;
> - case 2:
> - *seqno = &layout->os_area.msg_seqno_2;
> - key = layout->vmpck2;
> - break;
> - case 3:
> - *seqno = &layout->os_area.msg_seqno_3;
> - key = layout->vmpck3;
> - break;
> - default:
> - break;
> - }
> + dev->vmpck_id = vmpck_id;
> + dev->vmpck = dev->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
> + dev->os_area_msg_seqno = &dev->layout->os_area.msg_seqno_0 + vmpck_id;
>
> - return key;
> + return true;
> }
>
> static int __init sev_guest_probe(struct platform_device *pdev)
> @@ -682,8 +666,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> goto e_unmap;
>
> ret = -EINVAL;
> - snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
> - if (!snp_dev->vmpck) {
> + snp_dev->layout = layout;
> + if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
> dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
> goto e_unmap;
> }
> @@ -697,7 +681,6 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> mutex_init(&snp_dev->cmd_mutex);
> platform_set_drvdata(pdev, snp_dev);
> snp_dev->dev = dev;
> - snp_dev->layout = layout;
>
> /* Allocate the shared page used for the request and response message. */
> snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck
2023-04-03 20:26 ` Tom Lendacky
@ 2023-04-05 6:18 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 6:18 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 1:56 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> Simplify get_vmpck and prepare it to be used as an API. Update the
>> snp_guest_dev structure in snp_assign_vmpck(). Added vmpck_id to the
>> snp_guest_dev structure which can be used in SNP guest request API and
>> will remove direct use of vmpck_id command line parameter.
>
> This needs to say more about why you're doing this. The first two
> sentences need more explanation as they don't really stand on their own.
> How about the this:
Add vmpck_id to snp_guest_dev struct instead of directly using vmpck_id
command line parameter. Each SNP guest has four VMPCK, which the firmware
generates and provides to the guest in a special secrets page. Each VMPCK
has a sequence number. Simplify assignment of key and sequence number
instead of using a switch case.
> The last sentence talks about removing direct use of vmpck_id, so you
> should probably do that in this patch since it seems to be the real
> reason for all this.
I did change all places using vmpck_id to snp_dev->vmpck_id. This is the
only place the command line parameter is being used.
+ if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
Regards
Nikunj
>
> Thanks,
> Tom
>
>>
>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>> ---
>> drivers/virt/coco/sev-guest/sev-guest.c | 41 ++++++++-----------------
>> 1 file changed, 12 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
>> index ec93dee330f2..4901ebc8fa1a 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.c
>> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
>> @@ -45,6 +45,7 @@ struct snp_guest_dev {
>> struct snp_req_data input;
>> u32 *os_area_msg_seqno;
>> u8 *vmpck;
>> + u8 vmpck_id;
>> };
>> static u32 vmpck_id;
>> @@ -80,7 +81,7 @@ static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
>> static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
>> {
>> dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
>> - vmpck_id);
>> + snp_dev->vmpck_id);
>> memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
>> snp_dev->vmpck = NULL;
>> }
>> @@ -339,7 +340,7 @@ static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
>> memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
>> /* Encrypt the userspace provided payload */
>> - rc = enc_payload(snp_dev, seqno, req, vmpck_id);
>> + rc = enc_payload(snp_dev, seqno, req, snp_dev->vmpck_id);
>> if (rc)
>> return rc;
>> @@ -364,7 +365,6 @@ static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues
>> return 0;
>> }
>> -
>> static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
>> u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
>> u32 resp_sz, __u64 *fw_err)
>> @@ -625,32 +625,16 @@ static const struct file_operations snp_guest_fops = {
>> .unlocked_ioctl = snp_guest_ioctl,
>> };
>> -static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
>> +bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
>> {
>> - u8 *key = NULL;
>> + if (WARN_ON(vmpck_id > 3))
>> + return false;
>> - switch (id) {
>> - case 0:
>> - *seqno = &layout->os_area.msg_seqno_0;
>> - key = layout->vmpck0;
>> - break;
>> - case 1:
>> - *seqno = &layout->os_area.msg_seqno_1;
>> - key = layout->vmpck1;
>> - break;
>> - case 2:
>> - *seqno = &layout->os_area.msg_seqno_2;
>> - key = layout->vmpck2;
>> - break;
>> - case 3:
>> - *seqno = &layout->os_area.msg_seqno_3;
>> - key = layout->vmpck3;
>> - break;
>> - default:
>> - break;
>> - }
>> + dev->vmpck_id = vmpck_id;
>> + dev->vmpck = dev->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
>> + dev->os_area_msg_seqno = &dev->layout->os_area.msg_seqno_0 + vmpck_id;
>> - return key;
>> + return true;
>> }
>> static int __init sev_guest_probe(struct platform_device *pdev)
>> @@ -682,8 +666,8 @@ static int __init sev_guest_probe(struct platform_device *pdev)
>> goto e_unmap;
>> ret = -EINVAL;
>> - snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
>> - if (!snp_dev->vmpck) {
>> + snp_dev->layout = layout;
>> + if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
>> dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
>> goto e_unmap;
>> }
>> @@ -697,7 +681,6 @@ static int __init sev_guest_probe(struct platform_device *pdev)
>> mutex_init(&snp_dev->cmd_mutex);
>> platform_set_drvdata(pdev, snp_dev);
>> snp_dev->dev = dev;
>> - snp_dev->layout = layout;
>> /* Allocate the shared page used for the request and response message. */
>> snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
^ permalink raw reply [flat|nested] 33+ messages in thread
* Re: [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck
2023-03-26 14:46 ` [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck Nikunj A Dadhania
2023-04-03 20:26 ` Tom Lendacky
@ 2023-04-10 16:31 ` Peter Gonda
2023-04-14 4:51 ` Nikunj A. Dadhania
1 sibling, 1 reply; 33+ messages in thread
From: Peter Gonda @ 2023-04-10 16:31 UTC (permalink / raw)
To: Nikunj A Dadhania
Cc: linux-kernel, x86, bp, thomas.lendacky, dionnaglaze, seanjc,
pbonzini, michael.roth, ketanch
>
> -static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
> +bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
> {
> - u8 *key = NULL;
> + if (WARN_ON(vmpck_id > 3))
> + return false;
Should vmpck_id be a uint to match the module parameter or should we
check if vmpck_id < 0 ?
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck
2023-04-10 16:31 ` Peter Gonda
@ 2023-04-14 4:51 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-14 4:51 UTC (permalink / raw)
To: Peter Gonda
Cc: linux-kernel, x86, bp, thomas.lendacky, dionnaglaze, seanjc,
pbonzini, michael.roth, ketanch
On 4/10/2023 10:01 PM, Peter Gonda wrote:
>>
>> -static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
>> +bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
>> {
>> - u8 *key = NULL;
>> + if (WARN_ON(vmpck_id > 3))
>> + return false;
>
> Should vmpck_id be a uint to match the module parameter or should we
> check if vmpck_id < 0 ?
Thanks for pointing that out, I will make vmpck_id as a uint.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 05/11] x86/sev: Move and reorganize sev guest request api
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (3 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 04/11] virt: sev-guest: Add simplified helper to assign vmpck Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 21:01 ` Tom Lendacky
2023-03-26 14:46 ` [PATCH v2 06/11] x86/mm: Add generic guest initialization hook Nikunj A Dadhania
` (5 subsequent siblings)
10 siblings, 1 reply; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
For enabling Secure TSC, SEV-SNP guests need to communicate with the
security coprocessor really early during boot. Lot of the required
functions are implemented in the sev-guest driver. Move the required
functions and provide API to the driver to assign VM communications
key and send guest request.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/Kconfig | 1 +
.../x86/include/asm}/sev-guest.h | 6 +
arch/x86/include/asm/sev.h | 22 +
arch/x86/kernel/sev.c | 437 ++++++++++++++++-
drivers/virt/coco/sev-guest/Kconfig | 1 -
drivers/virt/coco/sev-guest/sev-guest.c | 455 ++----------------
6 files changed, 487 insertions(+), 435 deletions(-)
rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (86%)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a825bf031f49..42c52bfd2bac 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1545,6 +1545,7 @@ config AMD_MEM_ENCRYPT
select INSTRUCTION_DECODER
select ARCH_HAS_CC_PLATFORM
select X86_MEM_ENCRYPT
+ select CRYPTO_LIB_AESGCM
help
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory
diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/arch/x86/include/asm/sev-guest.h
similarity index 86%
rename from drivers/virt/coco/sev-guest/sev-guest.h
rename to arch/x86/include/asm/sev-guest.h
index d245578d988e..834cdae302ad 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -12,6 +12,9 @@
#include <linux/types.h>
+#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
+#define SNP_REQ_RETRY_DELAY (2*HZ)
+
#define MAX_AUTHTAG_LEN 32
#define AUTHTAG_LEN 16
#define AAD_LEN 48
@@ -72,6 +75,9 @@ struct snp_guest_req {
u8 msg_type;
};
+int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_guest_req *req);
+bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id);
+
static inline bool is_vmpck_empty(u8 *vmpck)
{
char zero_key[VMPCK_KEY_LEN] = {0};
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index ebc271bb6d8e..36868e21c3e0 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -9,6 +9,7 @@
#define __ASM_ENCRYPTED_STATE_H
#include <linux/types.h>
+#include <linux/miscdevice.h>
#include <asm/insn.h>
#include <asm/sev-common.h>
#include <asm/bootparam.h>
@@ -96,6 +97,27 @@ struct snp_req_data {
struct sev_guest_platform_data {
u64 secrets_gpa;
+
+ void *certs_data;
+ struct aesgcm_ctx *ctx;
+ struct snp_guest_msg *req, *resp;
+ struct snp_secrets_page_layout *layout;
+ struct snp_req_data input;
+ u8 *vmpck0;
+};
+
+struct snp_guest_dev {
+ struct device *dev;
+ struct miscdevice misc;
+
+ /* Mutex to serialize the shared buffer access and command handling. */
+ struct mutex cmd_mutex;
+
+ struct sev_guest_platform_data *pdata;
+
+ u32 *os_area_msg_seqno;
+ u8 *vmpck;
+ u8 vmpck_id;
};
/*
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 3f664ab277c4..c5ca97aab8c1 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -22,10 +22,13 @@
#include <linux/efi.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/psp-sev.h>
+#include <crypto/gcm.h>
#include <asm/cpu_entry_area.h>
#include <asm/stacktrace.h>
#include <asm/sev.h>
+#include <asm/sev-guest.h>
#include <asm/insn-eval.h>
#include <asm/fpu/xcr.h>
#include <asm/processor.h>
@@ -982,6 +985,427 @@ static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
free_page((unsigned long)vmsa);
}
+static struct sev_guest_platform_data *platform_data;
+
+/*
+ * If an error is received from the host or AMD Secure Processor (ASP) there
+ * are two options. Either retry the exact same encrypted request or discontinue
+ * using the VMPCK.
+ *
+ * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
+ * encrypt the requests. The IV for this scheme is the sequence number. GCM
+ * cannot tolerate IV reuse.
+ *
+ * The ASP FW v1.51 only increments the sequence numbers on a successful
+ * guest<->ASP back and forth and only accepts messages at its exact sequence
+ * number.
+ *
+ * So if the sequence number were to be reused the encryption scheme is
+ * vulnerable. If the sequence number were incremented for a fresh IV the ASP
+ * will reject the request.
+ */
+static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
+{
+ pr_alert("Disabling vmpck_id %d to prevent IV reuse.\n", snp_dev->vmpck_id);
+ memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
+ snp_dev->vmpck = NULL;
+}
+
+static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ u64 count;
+
+ lockdep_assert_held(&snp_dev->cmd_mutex);
+
+ /* Read the current message sequence counter from secrets pages */
+ count = *snp_dev->os_area_msg_seqno;
+
+ return count + 1;
+}
+
+/* Return a non-zero on success */
+static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ u64 count = __snp_get_msg_seqno(snp_dev);
+
+ /*
+ * The message sequence counter for the SNP guest request is a 64-bit
+ * value but the version 2 of GHCB specification defines a 32-bit storage
+ * for it. If the counter exceeds the 32-bit value then return zero.
+ * The caller should check the return value, but if the caller happens to
+ * not check the value and use it, then the firmware treats zero as an
+ * invalid number and will fail the message request.
+ */
+ if (count >= UINT_MAX) {
+ pr_err("SNP request message sequence counter overflow\n");
+ return 0;
+ }
+
+ return count;
+}
+
+static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
+{
+ /*
+ * The counter is also incremented by the PSP, so increment it by 2
+ * and save in secrets page.
+ */
+ *snp_dev->os_area_msg_seqno += 2;
+}
+
+static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
+{
+ struct aesgcm_ctx *ctx;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+ if (!ctx)
+ return NULL;
+
+ if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
+ pr_err("SNP: crypto init failed\n");
+ kfree(ctx);
+ return NULL;
+ }
+
+ return ctx;
+}
+
+static void free_shared_pages(void *buf, size_t sz)
+{
+ unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+ int ret;
+
+ if (!buf)
+ return;
+
+ ret = set_memory_encrypted((unsigned long)buf, npages);
+ if (ret) {
+ WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n");
+ return;
+ }
+
+ __free_pages(virt_to_page(buf), get_order(sz));
+}
+
+static void *alloc_shared_pages(size_t sz)
+{
+ unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+ struct page *page;
+ int ret;
+
+ page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
+ if (!page)
+ return NULL;
+
+ ret = set_memory_decrypted((unsigned long)page_address(page), npages);
+ if (ret) {
+ pr_err("%s: failed to mark page shared, ret=%d\n", __func__, ret);
+ __free_pages(page, get_order(sz));
+ return NULL;
+ }
+
+ return page_address(page);
+}
+
+static int snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
+{
+ u64 gpa;
+ int ret;
+
+ if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+ return -ENODEV;
+
+ gpa = get_secrets_page();
+ if (!gpa)
+ return -ENODEV;
+
+ pdata->layout = (__force void *)ioremap_encrypted(gpa, PAGE_SIZE);
+ if (!pdata->layout) {
+ pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n");
+ return -ENODEV;
+ }
+
+ ret = -EINVAL;
+ pdata->vmpck0 = pdata->layout->vmpck0;
+
+ /* Verify that VMPCK is not zero. */
+ if (is_vmpck_empty(pdata->vmpck0)) {
+ pr_err("vmpck id 0 is null\n");
+ goto e_unmap;
+ }
+
+ ret = -ENOMEM;
+ /* Allocate the shared page used for the request and response message. */
+ pdata->req = alloc_shared_pages(sizeof(struct snp_guest_msg));
+ if (!pdata->req)
+ goto e_unmap;
+
+ pdata->resp = alloc_shared_pages(sizeof(struct snp_guest_msg));
+ if (!pdata->resp)
+ goto e_free_request;
+
+ pdata->certs_data = alloc_shared_pages(SEV_FW_BLOB_MAX_SIZE);
+ if (!pdata->certs_data)
+ goto e_free_response;
+
+ ret = -EIO;
+ pdata->ctx = snp_init_crypto(pdata->vmpck0, VMPCK_KEY_LEN);
+ if (!pdata->ctx)
+ goto e_free_cert_data;
+
+ /* initial the input address for guest request */
+ pdata->input.req_gpa = __pa(pdata->req);
+ pdata->input.resp_gpa = __pa(pdata->resp);
+ pdata->input.data_gpa = __pa(pdata->certs_data);
+
+ return 0;
+
+e_free_cert_data:
+ free_shared_pages(pdata->certs_data, SEV_FW_BLOB_MAX_SIZE);
+e_free_response:
+ free_shared_pages(pdata->resp, sizeof(struct snp_guest_msg));
+e_free_request:
+ free_shared_pages(pdata->req, sizeof(struct snp_guest_msg));
+e_unmap:
+ iounmap(pdata->layout);
+
+ return ret;
+}
+
+static int __enc_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
+ void *plaintext, size_t len)
+{
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
+ u8 iv[GCM_AES_IV_SIZE] = {};
+
+ if (WARN_ON((hdr->msg_sz + ctx->authsize) > sizeof(msg->payload)))
+ return -EBADMSG;
+
+ memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ aesgcm_encrypt(ctx, msg->payload, plaintext, len, &hdr->algo, AAD_LEN,
+ iv, hdr->authtag);
+ return 0;
+}
+
+static int dec_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
+ void *plaintext, size_t len)
+{
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
+ u8 iv[GCM_AES_IV_SIZE] = {};
+
+ memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
+ if (aesgcm_decrypt(ctx, plaintext, msg->payload, len, &hdr->algo,
+ AAD_LEN, iv, hdr->authtag))
+ return 0;
+ else
+ return -EBADMSG;
+}
+
+static int verify_and_dec_payload(struct sev_guest_platform_data *pdata,
+ void *payload, u32 sz)
+{
+ struct snp_guest_msg *resp = pdata->resp;
+ struct snp_guest_msg *req = pdata->req;
+ struct snp_guest_msg_hdr *req_hdr = &req->hdr;
+ struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
+ struct aesgcm_ctx *ctx = pdata->ctx;
+
+ pr_debug("response [seqno %lld type %d version %d sz %d]\n",
+ resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
+ resp_hdr->msg_sz);
+
+ /* Verify that the sequence counter is incremented by 1 */
+ if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
+ return -EBADMSG;
+
+ /* Verify response message type and version number. */
+ if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
+ resp_hdr->msg_version != req_hdr->msg_version)
+ return -EBADMSG;
+
+ /*
+ * If the message size is greater than our buffer length then return
+ * an error.
+ */
+ if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
+ return -EBADMSG;
+
+ return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
+}
+
+static int enc_payload(struct sev_guest_platform_data *pdata, u64 seqno,
+ struct snp_guest_req *req, u8 vmpck_id)
+{
+ struct snp_guest_msg *msg = pdata->req;
+ struct snp_guest_msg_hdr *hdr = &msg->hdr;
+
+ memset(msg, 0, sizeof(*msg));
+
+ hdr->algo = SNP_AEAD_AES_256_GCM;
+ hdr->hdr_version = MSG_HDR_VER;
+ hdr->hdr_sz = sizeof(*hdr);
+ hdr->msg_type = req->msg_type;
+ hdr->msg_version = req->msg_version;
+ hdr->msg_seqno = seqno;
+ hdr->msg_vmpck = vmpck_id;
+ hdr->msg_sz = req->req_sz;
+
+ /* Verify the sequence number is non-zero */
+ if (!hdr->msg_seqno)
+ return -ENOSR;
+
+ pr_debug("request [seqno %lld type %d version %d sz %d]\n",
+ hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
+
+ return __enc_payload(pdata->ctx, msg, req->req_buf, req->req_sz);
+}
+
+static int __handle_guest_request(struct snp_guest_dev *snp_dev,
+ struct sev_guest_platform_data *pdata,
+ struct snp_guest_req *req)
+{
+ unsigned long err = 0xff, override_err = 0;
+ unsigned long req_start = jiffies;
+ unsigned int override_npages = 0;
+ int rc;
+
+retry_request:
+ /*
+ * Call firmware to process the request. In this function the encrypted
+ * message enters shared memory with the host. So after this call the
+ * sequence number must be incremented or the VMPCK must be deleted to
+ * prevent reuse of the IV.
+ */
+ rc = snp_issue_guest_request(req->exit_code, &pdata->input, &err);
+ switch (rc) {
+ case -ENOSPC:
+ /*
+ * If the extended guest request fails due to having too
+ * small of a certificate data buffer, retry the same
+ * guest request without the extended data request in
+ * order to increment the sequence number and thus avoid
+ * IV reuse.
+ */
+ override_npages = pdata->input.data_npages;
+ req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+
+ /*
+ * Override the error to inform callers the given extended
+ * request buffer size was too small and give the caller the
+ * required buffer size.
+ */
+ override_err = SNP_GUEST_REQ_INVALID_LEN;
+
+ /*
+ * If this call to the firmware succeeds, the sequence number can
+ * be incremented allowing for continued use of the VMPCK. If
+ * there is an error reflected in the return value, this value
+ * is checked further down and the result will be the deletion
+ * of the VMPCK and the error code being propagated back to the
+ * user as an ioctl() return code.
+ */
+ goto retry_request;
+
+ /*
+ * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
+ * throttled. Retry in the driver to avoid returning and reusing the
+ * message sequence number on a different message.
+ */
+ case -EAGAIN:
+ if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
+ rc = -ETIMEDOUT;
+ break;
+ }
+ schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
+ goto retry_request;
+ }
+
+ /*
+ * Increment the message sequence number. There is no harm in doing
+ * this now because decryption uses the value stored in the response
+ * structure and any failure will wipe the VMPCK, preventing further
+ * use anyway.
+ */
+ snp_inc_msg_seqno(snp_dev);
+
+ if (req->fw_err)
+ *req->fw_err = override_err ?: err;
+
+ if (override_npages)
+ pdata->input.data_npages = override_npages;
+
+ /*
+ * If an extended guest request was issued and the supplied certificate
+ * buffer was not large enough, a standard guest request was issued to
+ * prevent IV reuse. If the standard request was successful, return -EIO
+ * back to the caller as would have originally been returned.
+ */
+ if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)
+ return -EIO;
+
+ return rc;
+}
+
+int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
+{
+ struct sev_guest_platform_data *pdata;
+ u64 seqno;
+ int rc;
+
+ if (!snp_dev || !snp_dev->pdata || !req)
+ return -ENODEV;
+
+ pdata = snp_dev->pdata;
+
+ /* Get message sequence and verify that its a non-zero */
+ seqno = snp_get_msg_seqno(snp_dev);
+ if (!seqno)
+ return -EIO;
+
+ memset(pdata->resp, 0, sizeof(struct snp_guest_msg));
+
+ /* Encrypt the provided payload */
+ rc = enc_payload(pdata, seqno, req, snp_dev->vmpck_id);
+ if (rc)
+ return rc;
+
+ rc = __handle_guest_request(snp_dev, pdata, req);
+ if (rc) {
+ if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
+ return rc;
+
+ pr_alert("Detected error from ASP request. rc: %d, fw_err: %llu\n",
+ rc, *req->fw_err);
+ snp_disable_vmpck(snp_dev);
+ return rc;
+ }
+
+ rc = verify_and_dec_payload(pdata, req->resp_buf, req->resp_sz);
+ if (rc) {
+ pr_alert("Detected unexpected decode failure from ASP. rc: %d\n", rc);
+ snp_disable_vmpck(snp_dev);
+ return rc;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snp_send_guest_request);
+
+bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
+{
+ struct sev_guest_platform_data *pdata = dev->pdata;
+
+ if (!pdata || WARN_ON(vmpck_id > 3))
+ return false;
+
+ dev->vmpck_id = vmpck_id;
+ dev->vmpck = pdata->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
+ dev->os_area_msg_seqno = &pdata->layout->os_area.msg_seqno_0 + vmpck_id;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(snp_assign_vmpck);
+
static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
{
struct sev_es_save_area *cur_vmsa, *vmsa;
@@ -2247,18 +2671,17 @@ static struct platform_device sev_guest_device = {
static int __init snp_init_platform_device(void)
{
- struct sev_guest_platform_data data;
- u64 gpa;
-
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
- gpa = get_secrets_page();
- if (!gpa)
+ platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
+ if (!platform_data)
+ return -ENOMEM;
+
+ if (snp_setup_psp_messaging(platform_data))
return -ENODEV;
- data.secrets_gpa = gpa;
- if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
+ if (platform_device_add_data(&sev_guest_device, platform_data, sizeof(*platform_data)))
return -ENODEV;
if (platform_device_register(&sev_guest_device))
diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig
index bcc760bfb468..c130456ad401 100644
--- a/drivers/virt/coco/sev-guest/Kconfig
+++ b/drivers/virt/coco/sev-guest/Kconfig
@@ -2,7 +2,6 @@ config SEV_GUEST
tristate "AMD SEV Guest driver"
default m
depends on AMD_MEM_ENCRYPT
- select CRYPTO_LIB_AESGCM
help
SEV-SNP firmware provides the guest a mechanism to communicate with
the PSP without risk from a malicious hypervisor who wishes to read,
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 4901ebc8fa1a..a011df21c03a 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -24,110 +24,25 @@
#include <asm/svm.h>
#include <asm/sev.h>
-#include "sev-guest.h"
+#include <asm/sev-guest.h>
#define DEVICE_NAME "sev-guest"
-#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
-#define SNP_REQ_RETRY_DELAY (2*HZ)
-
-struct snp_guest_dev {
- struct device *dev;
- struct miscdevice misc;
-
- /* Mutex to serialize the shared buffer access and command handling. */
- struct mutex cmd_mutex;
-
- void *certs_data;
- struct aesgcm_ctx *ctx;
- struct snp_guest_msg *request, *response;
- struct snp_secrets_page_layout *layout;
- struct snp_req_data input;
- u32 *os_area_msg_seqno;
- u8 *vmpck;
- u8 vmpck_id;
-};
-
static u32 vmpck_id;
module_param(vmpck_id, uint, 0444);
MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
{
- if (snp_dev && snp_dev->ctx)
- return snp_dev->ctx->authsize;
+ struct sev_guest_platform_data *pdata = snp_dev->pdata;
+
+ if (pdata && pdata->ctx)
+ return pdata->ctx->authsize;
WARN_ONCE(1, "Unable to get crypto authsize\n");
return 0;
}
-/*
- * If an error is received from the host or AMD Secure Processor (ASP) there
- * are two options. Either retry the exact same encrypted request or discontinue
- * using the VMPCK.
- *
- * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
- * encrypt the requests. The IV for this scheme is the sequence number. GCM
- * cannot tolerate IV reuse.
- *
- * The ASP FW v1.51 only increments the sequence numbers on a successful
- * guest<->ASP back and forth and only accepts messages at its exact sequence
- * number.
- *
- * So if the sequence number were to be reused the encryption scheme is
- * vulnerable. If the sequence number were incremented for a fresh IV the ASP
- * will reject the request.
- */
-static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
-{
- dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
- snp_dev->vmpck_id);
- memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
- snp_dev->vmpck = NULL;
-}
-
-static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- u64 count;
-
- lockdep_assert_held(&snp_dev->cmd_mutex);
-
- /* Read the current message sequence counter from secrets pages */
- count = *snp_dev->os_area_msg_seqno;
-
- return count + 1;
-}
-
-/* Return a non-zero on success */
-static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- u64 count = __snp_get_msg_seqno(snp_dev);
-
- /*
- * The message sequence counter for the SNP guest request is a 64-bit
- * value but the version 2 of GHCB specification defines a 32-bit storage
- * for it. If the counter exceeds the 32-bit value then return zero.
- * The caller should check the return value, but if the caller happens to
- * not check the value and use it, then the firmware treats zero as an
- * invalid number and will fail the message request.
- */
- if (count >= UINT_MAX) {
- dev_err(snp_dev->dev, "request message sequence counter overflow\n");
- return 0;
- }
-
- return count;
-}
-
-static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
-{
- /*
- * The counter is also incremented by the PSP, so increment it by 2
- * and save in secrets page.
- */
- *snp_dev->os_area_msg_seqno += 2;
-}
-
static inline struct snp_guest_dev *to_snp_dev(struct file *file)
{
struct miscdevice *dev = file->private_data;
@@ -135,236 +50,6 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
return container_of(dev, struct snp_guest_dev, misc);
}
-static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
-{
- struct aesgcm_ctx *ctx;
-
- ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
- if (!ctx)
- return NULL;
-
- if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
- pr_err("SNP: crypto init failed\n");
- kfree(ctx);
- return NULL;
- }
-
- return ctx;
-}
-
-static int __enc_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
- void *plaintext, size_t len)
-{
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
- u8 iv[GCM_AES_IV_SIZE] = {};
-
- if (WARN_ON((hdr->msg_sz + ctx->authsize) > sizeof(msg->payload)))
- return -EBADMSG;
-
- memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
- aesgcm_encrypt(ctx, msg->payload, plaintext, len, &hdr->algo, AAD_LEN,
- iv, hdr->authtag);
- return 0;
-}
-
-static int dec_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
- void *plaintext, size_t len)
-{
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
- u8 iv[GCM_AES_IV_SIZE] = {};
-
- memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
- if (aesgcm_decrypt(ctx, plaintext, msg->payload, len, &hdr->algo,
- AAD_LEN, iv, hdr->authtag))
- return 0;
- else
- return -EBADMSG;
-}
-
-static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
-{
- struct snp_guest_msg *resp = snp_dev->response;
- struct snp_guest_msg *req = snp_dev->request;
- struct snp_guest_msg_hdr *req_hdr = &req->hdr;
- struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
- struct aesgcm_ctx *ctx = snp_dev->ctx;
-
- pr_debug("response [seqno %lld type %d version %d sz %d]\n",
- resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
- resp_hdr->msg_sz);
-
- /* Verify that the sequence counter is incremented by 1 */
- if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
- return -EBADMSG;
-
- /* Verify response message type and version number. */
- if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
- resp_hdr->msg_version != req_hdr->msg_version)
- return -EBADMSG;
-
- /*
- * If the message size is greater than our buffer length then return
- * an error.
- */
- if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
- return -EBADMSG;
-
- /* Decrypt the payload */
- return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
-}
-
-static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno,
- struct snp_guest_req *req, u8 __vmpck_id)
-{
- struct snp_guest_msg *msg = snp_dev->request;
- struct snp_guest_msg_hdr *hdr = &msg->hdr;
-
- memset(msg, 0, sizeof(*msg));
-
- hdr->algo = SNP_AEAD_AES_256_GCM;
- hdr->hdr_version = MSG_HDR_VER;
- hdr->hdr_sz = sizeof(*hdr);
- hdr->msg_type = req->msg_type;
- hdr->msg_version = req->msg_version;
- hdr->msg_seqno = seqno;
- hdr->msg_vmpck = __vmpck_id;
- hdr->msg_sz = req->req_sz;
-
- /* Verify the sequence number is non-zero */
- if (!hdr->msg_seqno)
- return -ENOSR;
-
- pr_debug("request [seqno %lld type %d version %d sz %d]\n",
- hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
-
- return __enc_payload(snp_dev->ctx, msg, req->req_buf, req->req_sz);
-}
-
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
-{
- unsigned long err = 0xff, override_err = 0;
- unsigned long req_start = jiffies;
- unsigned int override_npages = 0;
- int rc;
-
-retry_request:
- /*
- * Call firmware to process the request. In this function the encrypted
- * message enters shared memory with the host. So after this call the
- * sequence number must be incremented or the VMPCK must be deleted to
- * prevent reuse of the IV.
- */
- rc = snp_issue_guest_request(req->exit_code, &snp_dev->input, &err);
- switch (rc) {
- case -ENOSPC:
- /*
- * If the extended guest request fails due to having too
- * small of a certificate data buffer, retry the same
- * guest request without the extended data request in
- * order to increment the sequence number and thus avoid
- * IV reuse.
- */
- override_npages = snp_dev->input.data_npages;
- req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
-
- /*
- * Override the error to inform callers the given extended
- * request buffer size was too small and give the caller the
- * required buffer size.
- */
- override_err = SNP_GUEST_REQ_INVALID_LEN;
-
- /*
- * If this call to the firmware succeeds, the sequence number can
- * be incremented allowing for continued use of the VMPCK. If
- * there is an error reflected in the return value, this value
- * is checked further down and the result will be the deletion
- * of the VMPCK and the error code being propagated back to the
- * user as an ioctl() return code.
- */
- goto retry_request;
-
- /*
- * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
- * throttled. Retry in the driver to avoid returning and reusing the
- * message sequence number on a different message.
- */
- case -EAGAIN:
- if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
- rc = -ETIMEDOUT;
- break;
- }
- schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
- goto retry_request;
- }
-
- /*
- * Increment the message sequence number. There is no harm in doing
- * this now because decryption uses the value stored in the response
- * structure and any failure will wipe the VMPCK, preventing further
- * use anyway.
- */
- snp_inc_msg_seqno(snp_dev);
-
- if (req->fw_err)
- *req->fw_err = override_err ?: err;
-
- if (override_npages)
- snp_dev->input.data_npages = override_npages;
-
- /*
- * If an extended guest request was issued and the supplied certificate
- * buffer was not large enough, a standard guest request was issued to
- * prevent IV reuse. If the standard request was successful, return -EIO
- * back to the caller as would have originally been returned.
- */
- if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)
- return -EIO;
-
- return rc;
-}
-
-static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
-{
- u64 seqno;
- int rc;
-
- if (!snp_dev || !req)
- return -ENODEV;
-
- /* Get message sequence and verify that its a non-zero */
- seqno = snp_get_msg_seqno(snp_dev);
- if (!seqno)
- return -EIO;
-
- memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
-
- /* Encrypt the userspace provided payload */
- rc = enc_payload(snp_dev, seqno, req, snp_dev->vmpck_id);
- if (rc)
- return rc;
-
- rc = __handle_guest_request(snp_dev, req);
- if (rc) {
- if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
- return rc;
-
- dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n",
- rc, *req->fw_err);
- snp_disable_vmpck(snp_dev);
- return rc;
- }
-
- rc = verify_and_dec_payload(snp_dev, req->resp_buf, req->resp_sz);
- if (rc) {
- dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
- snp_disable_vmpck(snp_dev);
- return rc;
- }
-
- return 0;
-}
-
static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
u32 resp_sz, __u64 *fw_err)
@@ -463,12 +148,14 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
{
+ struct sev_guest_platform_data *pdata;
struct snp_ext_report_req req;
struct snp_report_resp *resp;
int ret, npages = 0, resp_len;
lockdep_assert_held(&snp_dev->cmd_mutex);
+ pdata = snp_dev->pdata;
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
@@ -492,7 +179,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
* the host. If host does not supply any certs in it, then copy
* zeros to indicate that certificate data was not provided.
*/
- memset(snp_dev->certs_data, 0, req.certs_len);
+ memset(pdata->certs_data, 0, req.certs_len);
npages = req.certs_len >> PAGE_SHIFT;
cmd:
/*
@@ -505,14 +192,14 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
if (!resp)
return -ENOMEM;
- snp_dev->input.data_npages = npages;
+ pdata->input.data_npages = npages;
ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version,
SNP_MSG_REPORT_REQ, &req.data,
sizeof(req.data), resp->data, resp_len, &arg->fw_err);
/* If certs length is invalid then copy the returned length */
if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) {
- req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
+ req.certs_len = pdata->input.data_npages << PAGE_SHIFT;
if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req)))
ret = -EFAULT;
@@ -522,7 +209,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
goto e_free;
if (npages &&
- copy_to_user((void __user *)req.certs_address, snp_dev->certs_data,
+ copy_to_user((void __user *)req.certs_address, pdata->certs_data,
req.certs_len)) {
ret = -EFAULT;
goto e_free;
@@ -583,68 +270,17 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
return ret;
}
-static void free_shared_pages(void *buf, size_t sz)
-{
- unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
- int ret;
-
- if (!buf)
- return;
-
- ret = set_memory_encrypted((unsigned long)buf, npages);
- if (ret) {
- WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n");
- return;
- }
-
- __free_pages(virt_to_page(buf), get_order(sz));
-}
-
-static void *alloc_shared_pages(struct device *dev, size_t sz)
-{
- unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
- struct page *page;
- int ret;
-
- page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
- if (!page)
- return NULL;
-
- ret = set_memory_decrypted((unsigned long)page_address(page), npages);
- if (ret) {
- dev_err(dev, "failed to mark page shared, ret=%d\n", ret);
- __free_pages(page, get_order(sz));
- return NULL;
- }
-
- return page_address(page);
-}
-
static const struct file_operations snp_guest_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = snp_guest_ioctl,
};
-bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
-{
- if (WARN_ON(vmpck_id > 3))
- return false;
-
- dev->vmpck_id = vmpck_id;
- dev->vmpck = dev->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
- dev->os_area_msg_seqno = &dev->layout->os_area.msg_seqno_0 + vmpck_id;
-
- return true;
-}
-
static int __init sev_guest_probe(struct platform_device *pdev)
{
- struct snp_secrets_page_layout *layout;
- struct sev_guest_platform_data *data;
+ struct sev_guest_platform_data *pdata;
struct device *dev = &pdev->dev;
struct snp_guest_dev *snp_dev;
struct miscdevice *misc;
- void __iomem *mapping;
int ret;
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
@@ -653,80 +289,48 @@ static int __init sev_guest_probe(struct platform_device *pdev)
if (!dev->platform_data)
return -ENODEV;
- data = (struct sev_guest_platform_data *)dev->platform_data;
- mapping = ioremap_encrypted(data->secrets_gpa, PAGE_SIZE);
- if (!mapping)
- return -ENODEV;
-
- layout = (__force void *)mapping;
-
- ret = -ENOMEM;
+ pdata = (struct sev_guest_platform_data *)dev->platform_data;
snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
if (!snp_dev)
- goto e_unmap;
+ return -ENOMEM;
ret = -EINVAL;
- snp_dev->layout = layout;
+ snp_dev->pdata = pdata;
if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
- goto e_unmap;
+ goto e_free_snpdev;
}
/* Verify that VMPCK is not zero. */
if (is_vmpck_empty(snp_dev->vmpck)) {
dev_err(dev, "vmpck id %d is null\n", vmpck_id);
- goto e_unmap;
+ goto e_free_snpdev;
+ }
+
+ /* Skip VMPCK0 initialization as the key is already initialized during early boot */
+ if (vmpck_id && aesgcm_expandkey(pdata->ctx, snp_dev->vmpck, VMPCK_KEY_LEN, AUTHTAG_LEN)) {
+ ret = -ENODEV;
+ goto e_free_snpdev;
}
mutex_init(&snp_dev->cmd_mutex);
platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
- /* Allocate the shared page used for the request and response message. */
- snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
- if (!snp_dev->request)
- goto e_unmap;
-
- snp_dev->response = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
- if (!snp_dev->response)
- goto e_free_request;
-
- snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE);
- if (!snp_dev->certs_data)
- goto e_free_response;
-
- ret = -EIO;
- snp_dev->ctx = snp_init_crypto(snp_dev->vmpck, VMPCK_KEY_LEN);
- if (!snp_dev->ctx)
- goto e_free_cert_data;
-
misc = &snp_dev->misc;
misc->minor = MISC_DYNAMIC_MINOR;
misc->name = DEVICE_NAME;
misc->fops = &snp_guest_fops;
- /* initial the input address for guest request */
- snp_dev->input.req_gpa = __pa(snp_dev->request);
- snp_dev->input.resp_gpa = __pa(snp_dev->response);
- snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
-
- ret = misc_register(misc);
+ ret = misc_register(misc);
if (ret)
- goto e_free_ctx;
+ goto e_free_snpdev;
dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
return 0;
-e_free_ctx:
- kfree(snp_dev->ctx);
-e_free_cert_data:
- free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
-e_free_response:
- free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
-e_free_request:
- free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
-e_unmap:
- iounmap(mapping);
+e_free_snpdev:
+ kfree(snp_dev);
return ret;
}
@@ -734,11 +338,8 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
{
struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
- free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
- free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
- free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
- kfree(snp_dev->ctx);
misc_deregister(&snp_dev->misc);
+ kfree(snp_dev);
return 0;
}
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 05/11] x86/sev: Move and reorganize sev guest request api
2023-03-26 14:46 ` [PATCH v2 05/11] x86/sev: Move and reorganize sev guest request api Nikunj A Dadhania
@ 2023-04-03 21:01 ` Tom Lendacky
2023-04-05 7:11 ` Nikunj A. Dadhania
0 siblings, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 21:01 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> For enabling Secure TSC, SEV-SNP guests need to communicate with the
> security coprocessor really early during boot. Lot of the required
s/security coprocessor really/AMD Secure Processor/
s/Lot/Many/
> functions are implemented in the sev-guest driver. Move the required
... in the sev-guest driver and therefore not available at early boot.
> functions and provide API to the driver to assign VM communications
s/provide API/provide an API/
s/to assign.*//
> key and send guest request.
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> arch/x86/Kconfig | 1 +
> .../x86/include/asm}/sev-guest.h | 6 +
> arch/x86/include/asm/sev.h | 22 +
> arch/x86/kernel/sev.c | 437 ++++++++++++++++-
> drivers/virt/coco/sev-guest/Kconfig | 1 -
> drivers/virt/coco/sev-guest/sev-guest.c | 455 ++----------------
> 6 files changed, 487 insertions(+), 435 deletions(-)
> rename {drivers/virt/coco/sev-guest => arch/x86/include/asm}/sev-guest.h (86%)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index a825bf031f49..42c52bfd2bac 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1545,6 +1545,7 @@ config AMD_MEM_ENCRYPT
> select INSTRUCTION_DECODER
> select ARCH_HAS_CC_PLATFORM
> select X86_MEM_ENCRYPT
> + select CRYPTO_LIB_AESGCM
> help
> Say yes to enable support for the encryption of system memory.
> This requires an AMD processor that supports Secure Memory
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/arch/x86/include/asm/sev-guest.h
> similarity index 86%
> rename from drivers/virt/coco/sev-guest/sev-guest.h
> rename to arch/x86/include/asm/sev-guest.h
> index d245578d988e..834cdae302ad 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.h
> +++ b/arch/x86/include/asm/sev-guest.h
> @@ -12,6 +12,9 @@
>
> #include <linux/types.h>
>
> +#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
> +#define SNP_REQ_RETRY_DELAY (2*HZ)
> +
> #define MAX_AUTHTAG_LEN 32
> #define AUTHTAG_LEN 16
> #define AAD_LEN 48
> @@ -72,6 +75,9 @@ struct snp_guest_req {
> u8 msg_type;
> };
>
> +int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_guest_req *req);
> +bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id);
> +
> static inline bool is_vmpck_empty(u8 *vmpck)
> {
> char zero_key[VMPCK_KEY_LEN] = {0};
> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
> index ebc271bb6d8e..36868e21c3e0 100644
> --- a/arch/x86/include/asm/sev.h
> +++ b/arch/x86/include/asm/sev.h
> @@ -9,6 +9,7 @@
> #define __ASM_ENCRYPTED_STATE_H
>
> #include <linux/types.h>
> +#include <linux/miscdevice.h>
> #include <asm/insn.h>
> #include <asm/sev-common.h>
> #include <asm/bootparam.h>
> @@ -96,6 +97,27 @@ struct snp_req_data {
>
> struct sev_guest_platform_data {
> u64 secrets_gpa;
> +
> + void *certs_data;
> + struct aesgcm_ctx *ctx;
> + struct snp_guest_msg *req, *resp;
> + struct snp_secrets_page_layout *layout;
> + struct snp_req_data input;
> + u8 *vmpck0;
Isn't this unneeded? You have the vmpck and vmpck_id in the snp_guest_dev
struct which will be set based on the module parameter, so vmpck0 and
associated checks shouldn't be needed.
> +};
> +
> +struct snp_guest_dev {
> + struct device *dev;
> + struct miscdevice misc;
> +
> + /* Mutex to serialize the shared buffer access and command handling. */
> + struct mutex cmd_mutex;
> +
> + struct sev_guest_platform_data *pdata;
> +
> + u32 *os_area_msg_seqno;
> + u8 *vmpck;
> + u8 vmpck_id;
> };
>
> /*
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 3f664ab277c4..c5ca97aab8c1 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -22,10 +22,13 @@
> #include <linux/efi.h>
> #include <linux/platform_device.h>
> #include <linux/io.h>
> +#include <linux/psp-sev.h>
> +#include <crypto/gcm.h>
>
> #include <asm/cpu_entry_area.h>
> #include <asm/stacktrace.h>
> #include <asm/sev.h>
> +#include <asm/sev-guest.h>
> #include <asm/insn-eval.h>
> #include <asm/fpu/xcr.h>
> #include <asm/processor.h>
> @@ -982,6 +985,427 @@ static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
> free_page((unsigned long)vmsa);
> }
>
> +static struct sev_guest_platform_data *platform_data;
> +
> +/*
> + * If an error is received from the host or AMD Secure Processor (ASP) there
> + * are two options. Either retry the exact same encrypted request or discontinue
> + * using the VMPCK.
> + *
> + * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
> + * encrypt the requests. The IV for this scheme is the sequence number. GCM
> + * cannot tolerate IV reuse.
> + *
> + * The ASP FW v1.51 only increments the sequence numbers on a successful
> + * guest<->ASP back and forth and only accepts messages at its exact sequence
> + * number.
> + *
> + * So if the sequence number were to be reused the encryption scheme is
> + * vulnerable. If the sequence number were incremented for a fresh IV the ASP
> + * will reject the request.
> + */
> +static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
> +{
> + pr_alert("Disabling vmpck_id %d to prevent IV reuse.\n", snp_dev->vmpck_id);
> + memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
> + snp_dev->vmpck = NULL;
> +}
> +
> +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> +{
> + u64 count;
> +
> + lockdep_assert_held(&snp_dev->cmd_mutex);
> +
> + /* Read the current message sequence counter from secrets pages */
> + count = *snp_dev->os_area_msg_seqno;
> +
> + return count + 1;
> +}
> +
> +/* Return a non-zero on success */
> +static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> +{
> + u64 count = __snp_get_msg_seqno(snp_dev);
> +
> + /*
> + * The message sequence counter for the SNP guest request is a 64-bit
> + * value but the version 2 of GHCB specification defines a 32-bit storage
> + * for it. If the counter exceeds the 32-bit value then return zero.
> + * The caller should check the return value, but if the caller happens to
> + * not check the value and use it, then the firmware treats zero as an
> + * invalid number and will fail the message request.
> + */
> + if (count >= UINT_MAX) {
> + pr_err("SNP request message sequence counter overflow\n");
> + return 0;
> + }
> +
> + return count;
> +}
> +
> +static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
> +{
> + /*
> + * The counter is also incremented by the PSP, so increment it by 2
> + * and save in secrets page.
> + */
> + *snp_dev->os_area_msg_seqno += 2;
> +}
> +
> +static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
> +{
> + struct aesgcm_ctx *ctx;
> +
> + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
> + if (!ctx)
> + return NULL;
> +
> + if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
> + pr_err("SNP: crypto init failed\n");
> + kfree(ctx);
> + return NULL;
> + }
> +
> + return ctx;
> +}
> +
> +static void free_shared_pages(void *buf, size_t sz)
> +{
> + unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> + int ret;
> +
> + if (!buf)
> + return;
> +
> + ret = set_memory_encrypted((unsigned long)buf, npages);
> + if (ret) {
> + WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n");
> + return;
> + }
> +
> + __free_pages(virt_to_page(buf), get_order(sz));
> +}
> +
> +static void *alloc_shared_pages(size_t sz)
> +{
> + unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> + struct page *page;
> + int ret;
> +
> + page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
> + if (!page)
> + return NULL;
> +
> + ret = set_memory_decrypted((unsigned long)page_address(page), npages);
> + if (ret) {
> + pr_err("%s: failed to mark page shared, ret=%d\n", __func__, ret);
> + __free_pages(page, get_order(sz));
> + return NULL;
> + }
> +
> + return page_address(page);
> +}
> +
> +static int snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
> +{
> + u64 gpa;
> + int ret;
> +
> + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
> + return -ENODEV;
> +
> + gpa = get_secrets_page();
> + if (!gpa)
> + return -ENODEV;
> +
> + pdata->layout = (__force void *)ioremap_encrypted(gpa, PAGE_SIZE);
> + if (!pdata->layout) {
> + pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n");
> + return -ENODEV;
> + }
> +
> + ret = -EINVAL;
> + pdata->vmpck0 = pdata->layout->vmpck0;
> +
> + /* Verify that VMPCK is not zero. */
> + if (is_vmpck_empty(pdata->vmpck0)) {
> + pr_err("vmpck id 0 is null\n");
> + goto e_unmap;
> + }
> +
> + ret = -ENOMEM;
> + /* Allocate the shared page used for the request and response message. */
> + pdata->req = alloc_shared_pages(sizeof(struct snp_guest_msg));
> + if (!pdata->req)
> + goto e_unmap;
> +
> + pdata->resp = alloc_shared_pages(sizeof(struct snp_guest_msg));
> + if (!pdata->resp)
> + goto e_free_request;
> +
> + pdata->certs_data = alloc_shared_pages(SEV_FW_BLOB_MAX_SIZE);
> + if (!pdata->certs_data)
> + goto e_free_response;
> +
> + ret = -EIO;
> + pdata->ctx = snp_init_crypto(pdata->vmpck0, VMPCK_KEY_LEN);
> + if (!pdata->ctx)
> + goto e_free_cert_data;
> +
> + /* initial the input address for guest request */
> + pdata->input.req_gpa = __pa(pdata->req);
> + pdata->input.resp_gpa = __pa(pdata->resp);
> + pdata->input.data_gpa = __pa(pdata->certs_data);
> +
> + return 0;
> +
> +e_free_cert_data:
> + free_shared_pages(pdata->certs_data, SEV_FW_BLOB_MAX_SIZE);
> +e_free_response:
> + free_shared_pages(pdata->resp, sizeof(struct snp_guest_msg));
> +e_free_request:
> + free_shared_pages(pdata->req, sizeof(struct snp_guest_msg));
> +e_unmap:
> + iounmap(pdata->layout);
> +
> + return ret;
> +}
> +
> +static int __enc_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
> + void *plaintext, size_t len)
> +{
> + struct snp_guest_msg_hdr *hdr = &msg->hdr;
> + u8 iv[GCM_AES_IV_SIZE] = {};
> +
> + if (WARN_ON((hdr->msg_sz + ctx->authsize) > sizeof(msg->payload)))
> + return -EBADMSG;
> +
> + memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> + aesgcm_encrypt(ctx, msg->payload, plaintext, len, &hdr->algo, AAD_LEN,
> + iv, hdr->authtag);
> + return 0;
> +}
> +
> +static int dec_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
> + void *plaintext, size_t len)
> +{
> + struct snp_guest_msg_hdr *hdr = &msg->hdr;
> + u8 iv[GCM_AES_IV_SIZE] = {};
> +
> + memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> + if (aesgcm_decrypt(ctx, plaintext, msg->payload, len, &hdr->algo,
> + AAD_LEN, iv, hdr->authtag))
> + return 0;
> + else
> + return -EBADMSG;
> +}
> +
> +static int verify_and_dec_payload(struct sev_guest_platform_data *pdata,
> + void *payload, u32 sz)
> +{
> + struct snp_guest_msg *resp = pdata->resp;
> + struct snp_guest_msg *req = pdata->req;
> + struct snp_guest_msg_hdr *req_hdr = &req->hdr;
> + struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
> + struct aesgcm_ctx *ctx = pdata->ctx;
> +
> + pr_debug("response [seqno %lld type %d version %d sz %d]\n",
> + resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
> + resp_hdr->msg_sz);
> +
> + /* Verify that the sequence counter is incremented by 1 */
> + if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
> + return -EBADMSG;
> +
> + /* Verify response message type and version number. */
> + if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
> + resp_hdr->msg_version != req_hdr->msg_version)
> + return -EBADMSG;
> +
> + /*
> + * If the message size is greater than our buffer length then return
> + * an error.
> + */
> + if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
> + return -EBADMSG;
> +
> + return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
> +}
> +
> +static int enc_payload(struct sev_guest_platform_data *pdata, u64 seqno,
> + struct snp_guest_req *req, u8 vmpck_id)
> +{
> + struct snp_guest_msg *msg = pdata->req;
> + struct snp_guest_msg_hdr *hdr = &msg->hdr;
> +
> + memset(msg, 0, sizeof(*msg));
> +
> + hdr->algo = SNP_AEAD_AES_256_GCM;
> + hdr->hdr_version = MSG_HDR_VER;
> + hdr->hdr_sz = sizeof(*hdr);
> + hdr->msg_type = req->msg_type;
> + hdr->msg_version = req->msg_version;
> + hdr->msg_seqno = seqno;
> + hdr->msg_vmpck = vmpck_id;
> + hdr->msg_sz = req->req_sz;
> +
> + /* Verify the sequence number is non-zero */
> + if (!hdr->msg_seqno)
> + return -ENOSR;
> +
> + pr_debug("request [seqno %lld type %d version %d sz %d]\n",
> + hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
> +
> + return __enc_payload(pdata->ctx, msg, req->req_buf, req->req_sz);
> +}
> +
> +static int __handle_guest_request(struct snp_guest_dev *snp_dev,
> + struct sev_guest_platform_data *pdata,
> + struct snp_guest_req *req)
> +{
> + unsigned long err = 0xff, override_err = 0;
> + unsigned long req_start = jiffies;
> + unsigned int override_npages = 0;
> + int rc;
> +
> +retry_request:
> + /*
> + * Call firmware to process the request. In this function the encrypted
> + * message enters shared memory with the host. So after this call the
> + * sequence number must be incremented or the VMPCK must be deleted to
> + * prevent reuse of the IV.
> + */
> + rc = snp_issue_guest_request(req->exit_code, &pdata->input, &err);
> + switch (rc) {
> + case -ENOSPC:
> + /*
> + * If the extended guest request fails due to having too
> + * small of a certificate data buffer, retry the same
> + * guest request without the extended data request in
> + * order to increment the sequence number and thus avoid
> + * IV reuse.
> + */
> + override_npages = pdata->input.data_npages;
> + req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
> +
> + /*
> + * Override the error to inform callers the given extended
> + * request buffer size was too small and give the caller the
> + * required buffer size.
> + */
> + override_err = SNP_GUEST_REQ_INVALID_LEN;
> +
> + /*
> + * If this call to the firmware succeeds, the sequence number can
> + * be incremented allowing for continued use of the VMPCK. If
> + * there is an error reflected in the return value, this value
> + * is checked further down and the result will be the deletion
> + * of the VMPCK and the error code being propagated back to the
> + * user as an ioctl() return code.
> + */
> + goto retry_request;
> +
> + /*
> + * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
> + * throttled. Retry in the driver to avoid returning and reusing the
> + * message sequence number on a different message.
> + */
> + case -EAGAIN:
> + if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
> + rc = -ETIMEDOUT;
> + break;
> + }
> + schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
> + goto retry_request;
> + }
> +
> + /*
> + * Increment the message sequence number. There is no harm in doing
> + * this now because decryption uses the value stored in the response
> + * structure and any failure will wipe the VMPCK, preventing further
> + * use anyway.
> + */
> + snp_inc_msg_seqno(snp_dev);
> +
> + if (req->fw_err)
> + *req->fw_err = override_err ?: err;
> +
> + if (override_npages)
> + pdata->input.data_npages = override_npages;
> +
> + /*
> + * If an extended guest request was issued and the supplied certificate
> + * buffer was not large enough, a standard guest request was issued to
> + * prevent IV reuse. If the standard request was successful, return -EIO
> + * back to the caller as would have originally been returned.
> + */
> + if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)
> + return -EIO;
> +
> + return rc;
> +}
> +
> +int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
> +{
> + struct sev_guest_platform_data *pdata;
> + u64 seqno;
> + int rc;
> +
> + if (!snp_dev || !snp_dev->pdata || !req)
> + return -ENODEV;
> +
> + pdata = snp_dev->pdata;
> +
> + /* Get message sequence and verify that its a non-zero */
> + seqno = snp_get_msg_seqno(snp_dev);
> + if (!seqno)
> + return -EIO;
> +
> + memset(pdata->resp, 0, sizeof(struct snp_guest_msg));
> +
> + /* Encrypt the provided payload */
> + rc = enc_payload(pdata, seqno, req, snp_dev->vmpck_id);
> + if (rc)
> + return rc;
> +
> + rc = __handle_guest_request(snp_dev, pdata, req);
> + if (rc) {
> + if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
> + return rc;
> +
> + pr_alert("Detected error from ASP request. rc: %d, fw_err: %llu\n",
> + rc, *req->fw_err);
> + snp_disable_vmpck(snp_dev);
> + return rc;
> + }
> +
> + rc = verify_and_dec_payload(pdata, req->resp_buf, req->resp_sz);
> + if (rc) {
> + pr_alert("Detected unexpected decode failure from ASP. rc: %d\n", rc);
> + snp_disable_vmpck(snp_dev);
> + return rc;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(snp_send_guest_request);
> +
> +bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
> +{
> + struct sev_guest_platform_data *pdata = dev->pdata;
> +
> + if (!pdata || WARN_ON(vmpck_id > 3))
> + return false;
> +
> + dev->vmpck_id = vmpck_id;
> + dev->vmpck = pdata->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
> + dev->os_area_msg_seqno = &pdata->layout->os_area.msg_seqno_0 + vmpck_id;
> +
> + return true;
> +}
> +EXPORT_SYMBOL_GPL(snp_assign_vmpck);
> +
> static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
> {
> struct sev_es_save_area *cur_vmsa, *vmsa;
> @@ -2247,18 +2671,17 @@ static struct platform_device sev_guest_device = {
>
> static int __init snp_init_platform_device(void)
> {
> - struct sev_guest_platform_data data;
> - u64 gpa;
> -
> if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
> return -ENODEV;
>
> - gpa = get_secrets_page();
> - if (!gpa)
> + platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
> + if (!platform_data)
> + return -ENOMEM;
> +
> + if (snp_setup_psp_messaging(platform_data))
This shouldn't be done here (or yet) since you only moving the routines.
The sev-guest driver should call this regardless of the vmpck_id value.
> return -ENODEV;
>
> - data.secrets_gpa = gpa;
> - if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
> + if (platform_device_add_data(&sev_guest_device, platform_data, sizeof(*platform_data)))
> return -ENODEV;
>
> if (platform_device_register(&sev_guest_device))
> diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig
> index bcc760bfb468..c130456ad401 100644
> --- a/drivers/virt/coco/sev-guest/Kconfig
> +++ b/drivers/virt/coco/sev-guest/Kconfig
> @@ -2,7 +2,6 @@ config SEV_GUEST
> tristate "AMD SEV Guest driver"
> default m
> depends on AMD_MEM_ENCRYPT
> - select CRYPTO_LIB_AESGCM
> help
> SEV-SNP firmware provides the guest a mechanism to communicate with
> the PSP without risk from a malicious hypervisor who wishes to read,
> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
> index 4901ebc8fa1a..a011df21c03a 100644
> --- a/drivers/virt/coco/sev-guest/sev-guest.c
> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
> @@ -24,110 +24,25 @@
> #include <asm/svm.h>
> #include <asm/sev.h>
>
> -#include "sev-guest.h"
> +#include <asm/sev-guest.h>
>
> #define DEVICE_NAME "sev-guest"
>
> -#define SNP_REQ_MAX_RETRY_DURATION (60*HZ)
> -#define SNP_REQ_RETRY_DELAY (2*HZ)
> -
> -struct snp_guest_dev {
> - struct device *dev;
> - struct miscdevice misc;
> -
> - /* Mutex to serialize the shared buffer access and command handling. */
> - struct mutex cmd_mutex;
> -
> - void *certs_data;
> - struct aesgcm_ctx *ctx;
> - struct snp_guest_msg *request, *response;
> - struct snp_secrets_page_layout *layout;
> - struct snp_req_data input;
> - u32 *os_area_msg_seqno;
> - u8 *vmpck;
> - u8 vmpck_id;
> -};
> -
> static u32 vmpck_id;
> module_param(vmpck_id, uint, 0444);
> MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP.");
>
> static inline unsigned int get_ctx_authsize(struct snp_guest_dev *snp_dev)
> {
> - if (snp_dev && snp_dev->ctx)
> - return snp_dev->ctx->authsize;
> + struct sev_guest_platform_data *pdata = snp_dev->pdata;
> +
> + if (pdata && pdata->ctx)
> + return pdata->ctx->authsize;
>
> WARN_ONCE(1, "Unable to get crypto authsize\n");
> return 0;
> }
>
> -/*
> - * If an error is received from the host or AMD Secure Processor (ASP) there
> - * are two options. Either retry the exact same encrypted request or discontinue
> - * using the VMPCK.
> - *
> - * This is because in the current encryption scheme GHCB v2 uses AES-GCM to
> - * encrypt the requests. The IV for this scheme is the sequence number. GCM
> - * cannot tolerate IV reuse.
> - *
> - * The ASP FW v1.51 only increments the sequence numbers on a successful
> - * guest<->ASP back and forth and only accepts messages at its exact sequence
> - * number.
> - *
> - * So if the sequence number were to be reused the encryption scheme is
> - * vulnerable. If the sequence number were incremented for a fresh IV the ASP
> - * will reject the request.
> - */
> -static void snp_disable_vmpck(struct snp_guest_dev *snp_dev)
> -{
> - dev_alert(snp_dev->dev, "Disabling vmpck_id %d to prevent IV reuse.\n",
> - snp_dev->vmpck_id);
> - memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN);
> - snp_dev->vmpck = NULL;
> -}
> -
> -static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> -{
> - u64 count;
> -
> - lockdep_assert_held(&snp_dev->cmd_mutex);
> -
> - /* Read the current message sequence counter from secrets pages */
> - count = *snp_dev->os_area_msg_seqno;
> -
> - return count + 1;
> -}
> -
> -/* Return a non-zero on success */
> -static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev)
> -{
> - u64 count = __snp_get_msg_seqno(snp_dev);
> -
> - /*
> - * The message sequence counter for the SNP guest request is a 64-bit
> - * value but the version 2 of GHCB specification defines a 32-bit storage
> - * for it. If the counter exceeds the 32-bit value then return zero.
> - * The caller should check the return value, but if the caller happens to
> - * not check the value and use it, then the firmware treats zero as an
> - * invalid number and will fail the message request.
> - */
> - if (count >= UINT_MAX) {
> - dev_err(snp_dev->dev, "request message sequence counter overflow\n");
> - return 0;
> - }
> -
> - return count;
> -}
> -
> -static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev)
> -{
> - /*
> - * The counter is also incremented by the PSP, so increment it by 2
> - * and save in secrets page.
> - */
> - *snp_dev->os_area_msg_seqno += 2;
> -}
> -
> static inline struct snp_guest_dev *to_snp_dev(struct file *file)
> {
> struct miscdevice *dev = file->private_data;
> @@ -135,236 +50,6 @@ static inline struct snp_guest_dev *to_snp_dev(struct file *file)
> return container_of(dev, struct snp_guest_dev, misc);
> }
>
> -static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
> -{
> - struct aesgcm_ctx *ctx;
> -
> - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
> - if (!ctx)
> - return NULL;
> -
> - if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) {
> - pr_err("SNP: crypto init failed\n");
> - kfree(ctx);
> - return NULL;
> - }
> -
> - return ctx;
> -}
> -
> -static int __enc_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
> - void *plaintext, size_t len)
> -{
> - struct snp_guest_msg_hdr *hdr = &msg->hdr;
> - u8 iv[GCM_AES_IV_SIZE] = {};
> -
> - if (WARN_ON((hdr->msg_sz + ctx->authsize) > sizeof(msg->payload)))
> - return -EBADMSG;
> -
> - memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> - aesgcm_encrypt(ctx, msg->payload, plaintext, len, &hdr->algo, AAD_LEN,
> - iv, hdr->authtag);
> - return 0;
> -}
> -
> -static int dec_payload(struct aesgcm_ctx *ctx, struct snp_guest_msg *msg,
> - void *plaintext, size_t len)
> -{
> - struct snp_guest_msg_hdr *hdr = &msg->hdr;
> - u8 iv[GCM_AES_IV_SIZE] = {};
> -
> - memcpy(iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno));
> - if (aesgcm_decrypt(ctx, plaintext, msg->payload, len, &hdr->algo,
> - AAD_LEN, iv, hdr->authtag))
> - return 0;
> - else
> - return -EBADMSG;
> -}
> -
> -static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
> -{
> - struct snp_guest_msg *resp = snp_dev->response;
> - struct snp_guest_msg *req = snp_dev->request;
> - struct snp_guest_msg_hdr *req_hdr = &req->hdr;
> - struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
> - struct aesgcm_ctx *ctx = snp_dev->ctx;
> -
> - pr_debug("response [seqno %lld type %d version %d sz %d]\n",
> - resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version,
> - resp_hdr->msg_sz);
> -
> - /* Verify that the sequence counter is incremented by 1 */
> - if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
> - return -EBADMSG;
> -
> - /* Verify response message type and version number. */
> - if (resp_hdr->msg_type != (req_hdr->msg_type + 1) ||
> - resp_hdr->msg_version != req_hdr->msg_version)
> - return -EBADMSG;
> -
> - /*
> - * If the message size is greater than our buffer length then return
> - * an error.
> - */
> - if (unlikely((resp_hdr->msg_sz + ctx->authsize) > sz))
> - return -EBADMSG;
> -
> - /* Decrypt the payload */
> - return dec_payload(ctx, resp, payload, resp_hdr->msg_sz);
> -}
> -
> -static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno,
> - struct snp_guest_req *req, u8 __vmpck_id)
> -{
> - struct snp_guest_msg *msg = snp_dev->request;
> - struct snp_guest_msg_hdr *hdr = &msg->hdr;
> -
> - memset(msg, 0, sizeof(*msg));
> -
> - hdr->algo = SNP_AEAD_AES_256_GCM;
> - hdr->hdr_version = MSG_HDR_VER;
> - hdr->hdr_sz = sizeof(*hdr);
> - hdr->msg_type = req->msg_type;
> - hdr->msg_version = req->msg_version;
> - hdr->msg_seqno = seqno;
> - hdr->msg_vmpck = __vmpck_id;
> - hdr->msg_sz = req->req_sz;
> -
> - /* Verify the sequence number is non-zero */
> - if (!hdr->msg_seqno)
> - return -ENOSR;
> -
> - pr_debug("request [seqno %lld type %d version %d sz %d]\n",
> - hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz);
> -
> - return __enc_payload(snp_dev->ctx, msg, req->req_buf, req->req_sz);
> -}
> -
> -static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
> -{
> - unsigned long err = 0xff, override_err = 0;
> - unsigned long req_start = jiffies;
> - unsigned int override_npages = 0;
> - int rc;
> -
> -retry_request:
> - /*
> - * Call firmware to process the request. In this function the encrypted
> - * message enters shared memory with the host. So after this call the
> - * sequence number must be incremented or the VMPCK must be deleted to
> - * prevent reuse of the IV.
> - */
> - rc = snp_issue_guest_request(req->exit_code, &snp_dev->input, &err);
> - switch (rc) {
> - case -ENOSPC:
> - /*
> - * If the extended guest request fails due to having too
> - * small of a certificate data buffer, retry the same
> - * guest request without the extended data request in
> - * order to increment the sequence number and thus avoid
> - * IV reuse.
> - */
> - override_npages = snp_dev->input.data_npages;
> - req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
> -
> - /*
> - * Override the error to inform callers the given extended
> - * request buffer size was too small and give the caller the
> - * required buffer size.
> - */
> - override_err = SNP_GUEST_REQ_INVALID_LEN;
> -
> - /*
> - * If this call to the firmware succeeds, the sequence number can
> - * be incremented allowing for continued use of the VMPCK. If
> - * there is an error reflected in the return value, this value
> - * is checked further down and the result will be the deletion
> - * of the VMPCK and the error code being propagated back to the
> - * user as an ioctl() return code.
> - */
> - goto retry_request;
> -
> - /*
> - * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
> - * throttled. Retry in the driver to avoid returning and reusing the
> - * message sequence number on a different message.
> - */
> - case -EAGAIN:
> - if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) {
> - rc = -ETIMEDOUT;
> - break;
> - }
> - schedule_timeout_killable(SNP_REQ_RETRY_DELAY);
> - goto retry_request;
> - }
> -
> - /*
> - * Increment the message sequence number. There is no harm in doing
> - * this now because decryption uses the value stored in the response
> - * structure and any failure will wipe the VMPCK, preventing further
> - * use anyway.
> - */
> - snp_inc_msg_seqno(snp_dev);
> -
> - if (req->fw_err)
> - *req->fw_err = override_err ?: err;
> -
> - if (override_npages)
> - snp_dev->input.data_npages = override_npages;
> -
> - /*
> - * If an extended guest request was issued and the supplied certificate
> - * buffer was not large enough, a standard guest request was issued to
> - * prevent IV reuse. If the standard request was successful, return -EIO
> - * back to the caller as would have originally been returned.
> - */
> - if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)
> - return -EIO;
> -
> - return rc;
> -}
> -
> -static int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req)
> -{
> - u64 seqno;
> - int rc;
> -
> - if (!snp_dev || !req)
> - return -ENODEV;
> -
> - /* Get message sequence and verify that its a non-zero */
> - seqno = snp_get_msg_seqno(snp_dev);
> - if (!seqno)
> - return -EIO;
> -
> - memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
> -
> - /* Encrypt the userspace provided payload */
> - rc = enc_payload(snp_dev, seqno, req, snp_dev->vmpck_id);
> - if (rc)
> - return rc;
> -
> - rc = __handle_guest_request(snp_dev, req);
> - if (rc) {
> - if (rc == -EIO && *req->fw_err == SNP_GUEST_REQ_INVALID_LEN)
> - return rc;
> -
> - dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n",
> - rc, *req->fw_err);
> - snp_disable_vmpck(snp_dev);
> - return rc;
> - }
> -
> - rc = verify_and_dec_payload(snp_dev, req->resp_buf, req->resp_sz);
> - if (rc) {
> - dev_alert(snp_dev->dev, "Detected unexpected decode failure from ASP. rc: %d\n", rc);
> - snp_disable_vmpck(snp_dev);
> - return rc;
> - }
> -
> - return 0;
> -}
> -
> static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, u8 msg_version,
> u8 msg_type, void *req_buf, size_t req_sz, void *resp_buf,
> u32 resp_sz, __u64 *fw_err)
> @@ -463,12 +148,14 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
>
> static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
> {
> + struct sev_guest_platform_data *pdata;
> struct snp_ext_report_req req;
> struct snp_report_resp *resp;
> int ret, npages = 0, resp_len;
>
> lockdep_assert_held(&snp_dev->cmd_mutex);
>
> + pdata = snp_dev->pdata;
> if (!arg->req_data || !arg->resp_data)
> return -EINVAL;
>
> @@ -492,7 +179,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
> * the host. If host does not supply any certs in it, then copy
> * zeros to indicate that certificate data was not provided.
> */
> - memset(snp_dev->certs_data, 0, req.certs_len);
> + memset(pdata->certs_data, 0, req.certs_len);
> npages = req.certs_len >> PAGE_SHIFT;
> cmd:
> /*
> @@ -505,14 +192,14 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
> if (!resp)
> return -ENOMEM;
>
> - snp_dev->input.data_npages = npages;
> + pdata->input.data_npages = npages;
> ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version,
> SNP_MSG_REPORT_REQ, &req.data,
> sizeof(req.data), resp->data, resp_len, &arg->fw_err);
>
> /* If certs length is invalid then copy the returned length */
> if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) {
> - req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
> + req.certs_len = pdata->input.data_npages << PAGE_SHIFT;
>
> if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req)))
> ret = -EFAULT;
> @@ -522,7 +209,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
> goto e_free;
>
> if (npages &&
> - copy_to_user((void __user *)req.certs_address, snp_dev->certs_data,
> + copy_to_user((void __user *)req.certs_address, pdata->certs_data,
> req.certs_len)) {
> ret = -EFAULT;
> goto e_free;
> @@ -583,68 +270,17 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
> return ret;
> }
>
> -static void free_shared_pages(void *buf, size_t sz)
> -{
> - unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> - int ret;
> -
> - if (!buf)
> - return;
> -
> - ret = set_memory_encrypted((unsigned long)buf, npages);
> - if (ret) {
> - WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n");
> - return;
> - }
> -
> - __free_pages(virt_to_page(buf), get_order(sz));
> -}
> -
> -static void *alloc_shared_pages(struct device *dev, size_t sz)
> -{
> - unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
> - struct page *page;
> - int ret;
> -
> - page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz));
> - if (!page)
> - return NULL;
> -
> - ret = set_memory_decrypted((unsigned long)page_address(page), npages);
> - if (ret) {
> - dev_err(dev, "failed to mark page shared, ret=%d\n", ret);
> - __free_pages(page, get_order(sz));
> - return NULL;
> - }
> -
> - return page_address(page);
> -}
> -
> static const struct file_operations snp_guest_fops = {
> .owner = THIS_MODULE,
> .unlocked_ioctl = snp_guest_ioctl,
> };
>
> -bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
> -{
> - if (WARN_ON(vmpck_id > 3))
> - return false;
> -
> - dev->vmpck_id = vmpck_id;
> - dev->vmpck = dev->layout->vmpck0 + vmpck_id * VMPCK_KEY_LEN;
> - dev->os_area_msg_seqno = &dev->layout->os_area.msg_seqno_0 + vmpck_id;
> -
> - return true;
> -}
> -
> static int __init sev_guest_probe(struct platform_device *pdev)
> {
> - struct snp_secrets_page_layout *layout;
> - struct sev_guest_platform_data *data;
> + struct sev_guest_platform_data *pdata;
> struct device *dev = &pdev->dev;
> struct snp_guest_dev *snp_dev;
> struct miscdevice *misc;
> - void __iomem *mapping;
> int ret;
>
> if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
> @@ -653,80 +289,48 @@ static int __init sev_guest_probe(struct platform_device *pdev)
> if (!dev->platform_data)
> return -ENODEV;
>
> - data = (struct sev_guest_platform_data *)dev->platform_data;
> - mapping = ioremap_encrypted(data->secrets_gpa, PAGE_SIZE);
> - if (!mapping)
> - return -ENODEV;
> -
> - layout = (__force void *)mapping;
> -
> - ret = -ENOMEM;
> + pdata = (struct sev_guest_platform_data *)dev->platform_data;
> snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
> if (!snp_dev)
> - goto e_unmap;
> + return -ENOMEM;
>
> ret = -EINVAL;
> - snp_dev->layout = layout;
> + snp_dev->pdata = pdata;
> if (!snp_assign_vmpck(snp_dev, vmpck_id)) {
> dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
> - goto e_unmap;
> + goto e_free_snpdev;
> }
>
> /* Verify that VMPCK is not zero. */
> if (is_vmpck_empty(snp_dev->vmpck)) {
> dev_err(dev, "vmpck id %d is null\n", vmpck_id);
> - goto e_unmap;
> + goto e_free_snpdev;
> + }
> +
> + /* Skip VMPCK0 initialization as the key is already initialized during early boot */
> + if (vmpck_id && aesgcm_expandkey(pdata->ctx, snp_dev->vmpck, VMPCK_KEY_LEN, AUTHTAG_LEN)) {
See previous comment. The sev-guest driver should be setting up everything
private to it no matter the vmpck to be used.
Thanks,
Tom
> + ret = -ENODEV;
> + goto e_free_snpdev;
> }
>
> mutex_init(&snp_dev->cmd_mutex);
> platform_set_drvdata(pdev, snp_dev);
> snp_dev->dev = dev;
>
> - /* Allocate the shared page used for the request and response message. */
> - snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
> - if (!snp_dev->request)
> - goto e_unmap;
> -
> - snp_dev->response = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));
> - if (!snp_dev->response)
> - goto e_free_request;
> -
> - snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE);
> - if (!snp_dev->certs_data)
> - goto e_free_response;
> -
> - ret = -EIO;
> - snp_dev->ctx = snp_init_crypto(snp_dev->vmpck, VMPCK_KEY_LEN);
> - if (!snp_dev->ctx)
> - goto e_free_cert_data;
> -
> misc = &snp_dev->misc;
> misc->minor = MISC_DYNAMIC_MINOR;
> misc->name = DEVICE_NAME;
> misc->fops = &snp_guest_fops;
>
> - /* initial the input address for guest request */
> - snp_dev->input.req_gpa = __pa(snp_dev->request);
> - snp_dev->input.resp_gpa = __pa(snp_dev->response);
> - snp_dev->input.data_gpa = __pa(snp_dev->certs_data);
> -
> - ret = misc_register(misc);
> + ret = misc_register(misc);
> if (ret)
> - goto e_free_ctx;
> + goto e_free_snpdev;
>
> dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id);
> return 0;
>
> -e_free_ctx:
> - kfree(snp_dev->ctx);
> -e_free_cert_data:
> - free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
> -e_free_response:
> - free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> -e_free_request:
> - free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> -e_unmap:
> - iounmap(mapping);
> +e_free_snpdev:
> + kfree(snp_dev);
> return ret;
> }
>
> @@ -734,11 +338,8 @@ static int __exit sev_guest_remove(struct platform_device *pdev)
> {
> struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev);
>
> - free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE);
> - free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg));
> - free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg));
> - kfree(snp_dev->ctx);
> misc_deregister(&snp_dev->misc);
> + kfree(snp_dev);
>
> return 0;
> }
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 05/11] x86/sev: Move and reorganize sev guest request api
2023-04-03 21:01 ` Tom Lendacky
@ 2023-04-05 7:11 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 7:11 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 2:31 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> For enabling Secure TSC, SEV-SNP guests need to communicate with the
>> security coprocessor really early during boot. Lot of the required
>
> s/security coprocessor really/AMD Secure Processor/
>
> s/Lot/Many/
>
>> functions are implemented in the sev-guest driver. Move the required
>
> ... in the sev-guest driver and therefore not available at early boot.
>
>> functions and provide API to the driver to assign VM communications
>
> s/provide API/provide an API/
>
> s/to assign.*//
>
>> key and send guest request.
Sure will change.
>> @@ -96,6 +97,27 @@ struct snp_req_data {
>> struct sev_guest_platform_data {
>> u64 secrets_gpa;
>> +
>> + void *certs_data;
>> + struct aesgcm_ctx *ctx;
>> + struct snp_guest_msg *req, *resp;
>> + struct snp_secrets_page_layout *layout;
>> + struct snp_req_data input;
>> + u8 *vmpck0;
>
> Isn't this unneeded? You have the vmpck and vmpck_id in the snp_guest_dev struct which will be set based on the module parameter, so vmpck0 and associated checks shouldn't be needed.
Yes, this can be removed.
>> + platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
>> + if (!platform_data)
>> + return -ENOMEM;
>> +
>> + if (snp_setup_psp_messaging(platform_data))
>
> This shouldn't be done here (or yet) since you only moving the routines. The sev-guest driver should call this regardless of the vmpck_id value.
I am moving the routines and also making sure that sev-guest driver works with this change. So sev-guest driver will not need to call snp_setup_psp_messaging().
>> + }
>> +
>> + /* Skip VMPCK0 initialization as the key is already initialized during early boot */
>> + if (vmpck_id && aesgcm_expandkey(pdata->ctx, snp_dev->vmpck, VMPCK_KEY_LEN, AUTHTAG_LEN)) {
>
> See previous comment. The sev-guest driver should be setting up everything private to it no matter the vmpck to be used.
I will try this out, as for secure tsc the vmpck will be used once and the sequence number would have incremented. And VMPCK0 will be initialized twice.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 06/11] x86/mm: Add generic guest initialization hook
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (4 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 05/11] x86/sev: Move and reorganize sev guest request api Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-03-26 14:46 ` [PATCH v2 07/11] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests Nikunj A Dadhania
` (4 subsequent siblings)
10 siblings, 0 replies; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
Add generic enc_init guest hook for performing any type of
initialization that is vendor specific.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/include/asm/x86_init.h | 2 ++
arch/x86/kernel/x86_init.c | 2 ++
arch/x86/mm/mem_encrypt.c | 3 +++
3 files changed, 7 insertions(+)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index c1c8c581759d..4026ac30a79f 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -148,12 +148,14 @@ struct x86_init_acpi {
* @enc_status_change_finish Notify HV after the encryption status of a range is changed
* @enc_tlb_flush_required Returns true if a TLB flush is needed before changing page encryption status
* @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status
+ * @enc_init Prepare and initialize encryption features
*/
struct x86_guest {
void (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
bool (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
bool (*enc_tlb_flush_required)(bool enc);
bool (*enc_cache_flush_required)(void);
+ void (*enc_init)(void);
};
/**
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index ef80d361b463..a71996e51a9c 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -134,6 +134,7 @@ static void enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool
static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return false; }
static bool enc_tlb_flush_required_noop(bool enc) { return false; }
static bool enc_cache_flush_required_noop(void) { return false; }
+static void enc_init_noop(void) { }
struct x86_platform_ops x86_platform __ro_after_init = {
.calibrate_cpu = native_calibrate_cpu_early,
@@ -155,6 +156,7 @@ struct x86_platform_ops x86_platform __ro_after_init = {
.enc_status_change_finish = enc_status_change_finish_noop,
.enc_tlb_flush_required = enc_tlb_flush_required_noop,
.enc_cache_flush_required = enc_cache_flush_required_noop,
+ .enc_init = enc_init_noop,
},
};
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 9f27e14e185f..01abecc9a774 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -84,5 +84,8 @@ void __init mem_encrypt_init(void)
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
+ if (x86_platform.guest.enc_init)
+ x86_platform.guest.enc_init();
+
print_mem_encrypt_feature_info();
}
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* [PATCH v2 07/11] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (5 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 06/11] x86/mm: Add generic guest initialization hook Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 21:15 ` Tom Lendacky
2023-03-26 14:46 ` [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests Nikunj A Dadhania
` (3 subsequent siblings)
10 siblings, 1 reply; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
Secure TSC enabled guests should not write MSR_IA32_TSC(10H) register
as the subsequent TSC value reads are undefined. MSR_IA32_TSC related
accesses should not exit to the hypervisor for such guests.
Accesses to MSR_IA32_TSC needs special handling in the #VC handler for
the guests with Secure TSC enabled. Writes to MSR_IA32_TSC should be
ignored, and reads of MSR_IA32_TSC should return the result of the
RDTSC instruction.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/kernel/sev.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c5ca97aab8c1..3750e545d688 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1642,6 +1642,30 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
/* Is it a WRMSR? */
exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0;
+ /*
+ * TSC related accesses should not exit to the hypervisor when a
+ * guest is executing with SecureTSC enabled, so special handling
+ * is required for accesses of MSR_IA32_TSC:
+ *
+ * Writes: Writing to MSR_IA32_TSC can cause subsequent reads
+ * of the TSC to return undefined values, so ignore all
+ * writes.
+ * Reads: Reads of MSR_IA32_TSC should return the current TSC
+ * value, use the value returned by RDTSC.
+ */
+ if (regs->cx == MSR_IA32_TSC && (sev_status & MSR_AMD64_SNP_SECURE_TSC)) {
+ u64 tsc;
+
+ if (exit_info_1)
+ return ES_OK;
+
+ tsc = rdtsc();
+ regs->ax = UINT_MAX & tsc;
+ regs->dx = UINT_MAX & (tsc >> 32);
+
+ return ES_OK;
+ }
+
ghcb_set_rcx(ghcb, regs->cx);
if (exit_info_1) {
ghcb_set_rax(ghcb, regs->ax);
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 07/11] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests
2023-03-26 14:46 ` [PATCH v2 07/11] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests Nikunj A Dadhania
@ 2023-04-03 21:15 ` Tom Lendacky
0 siblings, 0 replies; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 21:15 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> Secure TSC enabled guests should not write MSR_IA32_TSC(10H) register
> as the subsequent TSC value reads are undefined. MSR_IA32_TSC related
> accesses should not exit to the hypervisor for such guests.
>
> Accesses to MSR_IA32_TSC needs special handling in the #VC handler for
> the guests with Secure TSC enabled. Writes to MSR_IA32_TSC should be
> ignored, and reads of MSR_IA32_TSC should return the result of the
> RDTSC instruction.
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
> arch/x86/kernel/sev.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index c5ca97aab8c1..3750e545d688 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -1642,6 +1642,30 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
> /* Is it a WRMSR? */
> exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0;
>
> + /*
> + * TSC related accesses should not exit to the hypervisor when a
> + * guest is executing with SecureTSC enabled, so special handling
> + * is required for accesses of MSR_IA32_TSC:
> + *
> + * Writes: Writing to MSR_IA32_TSC can cause subsequent reads
> + * of the TSC to return undefined values, so ignore all
> + * writes.
> + * Reads: Reads of MSR_IA32_TSC should return the current TSC
> + * value, use the value returned by RDTSC.
> + */
> + if (regs->cx == MSR_IA32_TSC && (sev_status & MSR_AMD64_SNP_SECURE_TSC)) {
> + u64 tsc;
> +
> + if (exit_info_1)
> + return ES_OK;
> +
> + tsc = rdtsc();
> + regs->ax = UINT_MAX & tsc;
> + regs->dx = UINT_MAX & (tsc >> 32);
> +
> + return ES_OK;
> + }
> +
> ghcb_set_rcx(ghcb, regs->cx);
> if (exit_info_1) {
> ghcb_set_rax(ghcb, regs->ax);
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (6 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 07/11] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 21:41 ` Tom Lendacky
2023-04-10 17:14 ` Peter Gonda
2023-03-26 14:46 ` [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available Nikunj A Dadhania
` (2 subsequent siblings)
10 siblings, 2 replies; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
Add support for Secure TSC in SNP enabled guests. Secure TSC
allows guest to securely use RDTSC/RDTSCP instructions as the
parameters being used cannot be changed by hypervisor once the
guest is launched.
During the boot-up of the secondary cpus, SecureTSC enabled
guests need to query TSC info from Security processor (PSP).
This communication channel is encrypted between the security
processor and the guest, hypervisor is just the conduit to
deliver the guest messages to the security processor. Each
message is protected with an AEAD (AES-256 GCM). Use minimal
GCM library to encrypt/decrypt SNP Guest messages to communicate
with the PSP.
Moreover, the hypervisor should not be intercepting RDTSC/RDTSCP
when Secure TSC is enabled. A #VC exception will be generated if
the RDTSC/RDTSCP instructions are being intercepted. If this should
occur and Secure TSC is enabled, terminate guest execution.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/include/asm/sev-guest.h | 18 +++++++
arch/x86/include/asm/sev.h | 2 +
arch/x86/include/asm/svm.h | 6 ++-
arch/x86/kernel/sev-shared.c | 7 +++
arch/x86/kernel/sev.c | 92 +++++++++++++++++++++++++++++---
arch/x86/mm/mem_encrypt_amd.c | 6 +++
include/linux/cc_platform.h | 8 +++
7 files changed, 131 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
index 834cdae302ad..d5ed041ce06b 100644
--- a/arch/x86/include/asm/sev-guest.h
+++ b/arch/x86/include/asm/sev-guest.h
@@ -37,6 +37,8 @@ enum msg_type {
SNP_MSG_ABSORB_RSP,
SNP_MSG_VMRK_REQ,
SNP_MSG_VMRK_RSP,
+ SNP_MSG_TSC_INFO_REQ = 17,
+ SNP_MSG_TSC_INFO_RSP,
SNP_MSG_TYPE_MAX
};
@@ -75,6 +77,22 @@ struct snp_guest_req {
u8 msg_type;
};
+struct snp_tsc_info_req {
+#define SNP_TSC_INFO_REQ_SZ 128
+ /* Must be zero filled */
+ u8 rsvd[SNP_TSC_INFO_REQ_SZ];
+} __packed;
+
+struct snp_tsc_info_resp {
+ /* Status of TSC_INFO message */
+ u32 status;
+ u32 rsvd1;
+ u64 tsc_scale;
+ u64 tsc_offset;
+ u64 tsc_factor;
+ u8 rsvd2[96];
+} __packed;
+
int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_guest_req *req);
bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id);
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 36868e21c3e0..d05cbab5e9e0 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -218,6 +218,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
void snp_set_wakeup_secondary_cpu(void);
bool snp_init(struct boot_params *bp);
void __init __noreturn snp_abort(void);
+bool __init snp_secure_tsc_prepare(void);
int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
@@ -238,6 +239,7 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npag
static inline void snp_set_wakeup_secondary_cpu(void) { }
static inline bool snp_init(struct boot_params *bp) { return false; }
static inline void snp_abort(void) { }
+static inline bool __init snp_secure_tsc_prepare(void) { return false; }
static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input,
unsigned long *fw_err)
{
diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 770dcf75eaa9..c781f8e0aae4 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -404,7 +404,9 @@ struct sev_es_save_area {
u8 reserved_0x298[80];
u32 pkru;
u32 tsc_aux;
- u8 reserved_0x2f0[24];
+ u64 tsc_scale;
+ u64 tsc_offset;
+ u8 reserved_0x300[8];
u64 rcx;
u64 rdx;
u64 rbx;
@@ -536,7 +538,7 @@ static inline void __unused_size_checks(void)
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298);
- BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0);
+ BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380);
BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0);
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 3a5b0c9c4fcc..1c22025b298f 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -912,6 +912,13 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb,
bool rdtscp = (exit_code == SVM_EXIT_RDTSCP);
enum es_result ret;
+ /*
+ * RDTSC and RDTSCP should not be intercepted when Secure TSC is
+ * enabled. Terminate the SNP guest when the interception is enabled.
+ */
+ if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
+ return ES_VMM_ERROR;
+
ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0);
if (ret != ES_OK)
return ret;
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 3750e545d688..280aaa1e6aad 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -72,6 +72,10 @@ static struct ghcb *boot_ghcb __section(".data");
/* Bitmap of SEV features supported by the hypervisor */
static u64 sev_hv_features __ro_after_init;
+/* Secure TSC values read using TSC_INFO SNP Guest request */
+static u64 guest_tsc_scale __ro_after_init;
+static u64 guest_tsc_offset __ro_after_init;
+
/* #VC handler runtime per-CPU data */
struct sev_es_runtime_data {
struct ghcb ghcb_page;
@@ -1107,7 +1111,7 @@ static void *alloc_shared_pages(size_t sz)
return page_address(page);
}
-static int snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
+static int __init snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
{
u64 gpa;
int ret;
@@ -1406,6 +1410,80 @@ bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
}
EXPORT_SYMBOL_GPL(snp_assign_vmpck);
+static int __init snp_get_tsc_info(void)
+{
+ u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN];
+ struct snp_tsc_info_resp tsc_resp = {0};
+ struct snp_tsc_info_req tsc_req;
+ struct snp_guest_req req;
+ struct snp_guest_dev dev;
+ int rc, resp_len;
+
+ /*
+ * The intermediate response buffer is used while decrypting the
+ * response payload. Make sure that it has enough space to cover the
+ * authtag.
+ */
+ resp_len = sizeof(tsc_resp) + AUTHTAG_LEN;
+ if (sizeof(buf) < resp_len)
+ return -EINVAL;
+
+ /* Zero the tsc_info_req */
+ memzero_explicit(&tsc_req, sizeof(tsc_req));
+ memzero_explicit(&req, sizeof(req));
+
+ dev.pdata = platform_data;
+ if (!snp_assign_vmpck(&dev, 0))
+ return -EINVAL;
+
+ req.msg_version = MSG_HDR_VER;
+ req.msg_type = SNP_MSG_TSC_INFO_REQ;
+ req.req_buf = &tsc_req;
+ req.req_sz = sizeof(tsc_req);
+ req.resp_buf = buf;
+ req.resp_sz = resp_len;
+ req.fw_err = NULL;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ rc = snp_send_guest_request(&dev, &req);
+ if (rc)
+ goto err_req;
+
+ memcpy(&tsc_resp, buf, sizeof(tsc_resp));
+ pr_debug("%s: Valid response status %x scale %llx offset %llx factor %llx\n",
+ __func__, tsc_resp.status, tsc_resp.tsc_scale, tsc_resp.tsc_offset,
+ tsc_resp.tsc_factor);
+
+ guest_tsc_scale = tsc_resp.tsc_scale;
+ guest_tsc_offset = tsc_resp.tsc_offset;
+
+err_req:
+ /* The response buffer contains the sensitive data, explicitly clear it. */
+ memzero_explicit(buf, sizeof(buf));
+ memzero_explicit(&tsc_resp, sizeof(tsc_resp));
+ memzero_explicit(&req, sizeof(req));
+
+ return rc;
+}
+
+bool __init snp_secure_tsc_prepare(void)
+{
+ platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
+ if (!platform_data)
+ return false;
+
+ /* Initialize the PSP channel to send snp messages */
+ if (snp_setup_psp_messaging(platform_data))
+ sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+ if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
+ if (snp_get_tsc_info())
+ sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+ pr_info("SecureTSC enabled\n");
+ }
+ return true;
+}
+
static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
{
struct sev_es_save_area *cur_vmsa, *vmsa;
@@ -1506,6 +1584,12 @@ static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
vmsa->vmpl = 0;
vmsa->sev_features = sev_status >> 2;
+ /* Setting Secure TSC parameters */
+ if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
+ vmsa->tsc_scale = guest_tsc_scale;
+ vmsa->tsc_offset = guest_tsc_offset;
+ }
+
/* Switch the page over to a VMSA page now that it is initialized */
ret = snp_set_vmsa(vmsa, true);
if (ret) {
@@ -2698,11 +2782,7 @@ static int __init snp_init_platform_device(void)
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
- platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
- if (!platform_data)
- return -ENOMEM;
-
- if (snp_setup_psp_messaging(platform_data))
+ if (!platform_data->ctx)
return -ENODEV;
if (platform_device_add_data(&sev_guest_device, platform_data, sizeof(*platform_data)))
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 9c4d8dbcb129..7d2388e52b8f 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -215,6 +215,11 @@ void __init sme_map_bootdata(char *real_mode_data)
__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
}
+void __init amd_enc_init(void)
+{
+ snp_secure_tsc_prepare();
+}
+
void __init sev_setup_arch(void)
{
phys_addr_t total_mem = memblock_phys_mem_size();
@@ -501,6 +506,7 @@ void __init sme_early_init(void)
x86_platform.guest.enc_status_change_finish = amd_enc_status_change_finish;
x86_platform.guest.enc_tlb_flush_required = amd_enc_tlb_flush_required;
x86_platform.guest.enc_cache_flush_required = amd_enc_cache_flush_required;
+ x86_platform.guest.enc_init = amd_enc_init;
}
void __init mem_encrypt_free_decrypted_mem(void)
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
index cb0d6cd1c12f..e081ca4d5da2 100644
--- a/include/linux/cc_platform.h
+++ b/include/linux/cc_platform.h
@@ -90,6 +90,14 @@ enum cc_attr {
* Examples include TDX Guest.
*/
CC_ATTR_HOTPLUG_DISABLED,
+
+ /**
+ * @CC_ATTR_GUEST_SECURE_TSC: Secure TSC is active.
+ *
+ * The platform/OS is running as a guest/virtual machine and actively
+ * using AMD SEV-SNP Secure TSC feature.
+ */
+ CC_ATTR_GUEST_SECURE_TSC,
};
#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-03-26 14:46 ` [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests Nikunj A Dadhania
@ 2023-04-03 21:41 ` Tom Lendacky
2023-04-05 7:37 ` Nikunj A. Dadhania
2023-04-10 17:14 ` Peter Gonda
1 sibling, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 21:41 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> Add support for Secure TSC in SNP enabled guests. Secure TSC
> allows guest to securely use RDTSC/RDTSCP instructions as the
> parameters being used cannot be changed by hypervisor once the
> guest is launched.
>
> During the boot-up of the secondary cpus, SecureTSC enabled
> guests need to query TSC info from Security processor (PSP).
s/Security processor (PSP)/AMD Secure Processor/
> This communication channel is encrypted between the security
here as well.
> processor and the guest, hypervisor is just the conduit to
s/hypervisor/the hypervisor/
> deliver the guest messages to the security processor. Each
> message is protected with an AEAD (AES-256 GCM). Use minimal
> GCM library to encrypt/decrypt SNP Guest messages to communicate
> with the PSP.
>
> Moreover, the hypervisor should not be intercepting RDTSC/RDTSCP
> when Secure TSC is enabled. A #VC exception will be generated if
> the RDTSC/RDTSCP instructions are being intercepted. If this should
> occur and Secure TSC is enabled, terminate guest execution.
This seems like a separate patch.
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> arch/x86/include/asm/sev-guest.h | 18 +++++++
> arch/x86/include/asm/sev.h | 2 +
> arch/x86/include/asm/svm.h | 6 ++-
> arch/x86/kernel/sev-shared.c | 7 +++
> arch/x86/kernel/sev.c | 92 +++++++++++++++++++++++++++++---
> arch/x86/mm/mem_encrypt_amd.c | 6 +++
> include/linux/cc_platform.h | 8 +++
> 7 files changed, 131 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
> index 834cdae302ad..d5ed041ce06b 100644
> --- a/arch/x86/include/asm/sev-guest.h
> +++ b/arch/x86/include/asm/sev-guest.h
> @@ -37,6 +37,8 @@ enum msg_type {
> SNP_MSG_ABSORB_RSP,
> SNP_MSG_VMRK_REQ,
> SNP_MSG_VMRK_RSP,
> + SNP_MSG_TSC_INFO_REQ = 17,
> + SNP_MSG_TSC_INFO_RSP,
>
> SNP_MSG_TYPE_MAX
> };
> @@ -75,6 +77,22 @@ struct snp_guest_req {
> u8 msg_type;
> };
>
> +struct snp_tsc_info_req {
> +#define SNP_TSC_INFO_REQ_SZ 128
> + /* Must be zero filled */
> + u8 rsvd[SNP_TSC_INFO_REQ_SZ];
> +} __packed;
> +
> +struct snp_tsc_info_resp {
> + /* Status of TSC_INFO message */
> + u32 status;
> + u32 rsvd1;
> + u64 tsc_scale;
> + u64 tsc_offset;
> + u64 tsc_factor;
This should be a u32 ...
> + u8 rsvd2[96];
Which then makes this 100.
> +} __packed;
> +
> int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_guest_req *req);
> bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id);
>
> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
> index 36868e21c3e0..d05cbab5e9e0 100644
> --- a/arch/x86/include/asm/sev.h
> +++ b/arch/x86/include/asm/sev.h
> @@ -218,6 +218,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
> void snp_set_wakeup_secondary_cpu(void);
> bool snp_init(struct boot_params *bp);
> void __init __noreturn snp_abort(void);
> +bool __init snp_secure_tsc_prepare(void);
> int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
> #else
> static inline void sev_es_ist_enter(struct pt_regs *regs) { }
> @@ -238,6 +239,7 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npag
> static inline void snp_set_wakeup_secondary_cpu(void) { }
> static inline bool snp_init(struct boot_params *bp) { return false; }
> static inline void snp_abort(void) { }
> +static inline bool __init snp_secure_tsc_prepare(void) { return false; }
> static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input,
> unsigned long *fw_err)
> {
> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
> index 770dcf75eaa9..c781f8e0aae4 100644
> --- a/arch/x86/include/asm/svm.h
> +++ b/arch/x86/include/asm/svm.h
> @@ -404,7 +404,9 @@ struct sev_es_save_area {
> u8 reserved_0x298[80];
> u32 pkru;
> u32 tsc_aux;
> - u8 reserved_0x2f0[24];
> + u64 tsc_scale;
> + u64 tsc_offset;
> + u8 reserved_0x300[8];
> u64 rcx;
> u64 rdx;
> u64 rbx;
> @@ -536,7 +538,7 @@ static inline void __unused_size_checks(void)
> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0);
> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248);
> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298);
> - BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0);
> + BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300);
> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320);
> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380);
> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0);
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index 3a5b0c9c4fcc..1c22025b298f 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c
> @@ -912,6 +912,13 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb,
> bool rdtscp = (exit_code == SVM_EXIT_RDTSCP);
> enum es_result ret;
>
> + /*
> + * RDTSC and RDTSCP should not be intercepted when Secure TSC is
> + * enabled. Terminate the SNP guest when the interception is enabled.
> + */
> + if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
> + return ES_VMM_ERROR;
> +
> ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0);
> if (ret != ES_OK)
> return ret;
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 3750e545d688..280aaa1e6aad 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -72,6 +72,10 @@ static struct ghcb *boot_ghcb __section(".data");
> /* Bitmap of SEV features supported by the hypervisor */
> static u64 sev_hv_features __ro_after_init;
>
> +/* Secure TSC values read using TSC_INFO SNP Guest request */
> +static u64 guest_tsc_scale __ro_after_init;
> +static u64 guest_tsc_offset __ro_after_init;
> +
> /* #VC handler runtime per-CPU data */
> struct sev_es_runtime_data {
> struct ghcb ghcb_page;
> @@ -1107,7 +1111,7 @@ static void *alloc_shared_pages(size_t sz)
> return page_address(page);
> }
>
> -static int snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
> +static int __init snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
> {
> u64 gpa;
> int ret;
> @@ -1406,6 +1410,80 @@ bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
> }
> EXPORT_SYMBOL_GPL(snp_assign_vmpck);
>
> +static int __init snp_get_tsc_info(void)
> +{
> + u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN];
> + struct snp_tsc_info_resp tsc_resp = {0};
> + struct snp_tsc_info_req tsc_req;
> + struct snp_guest_req req;
> + struct snp_guest_dev dev;
> + int rc, resp_len;
> +
> + /*
> + * The intermediate response buffer is used while decrypting the
> + * response payload. Make sure that it has enough space to cover the
> + * authtag.
> + */
> + resp_len = sizeof(tsc_resp) + AUTHTAG_LEN;
> + if (sizeof(buf) < resp_len)
> + return -EINVAL;
> +
> + /* Zero the tsc_info_req */
> + memzero_explicit(&tsc_req, sizeof(tsc_req));
> + memzero_explicit(&req, sizeof(req));
> +
> + dev.pdata = platform_data;
> + if (!snp_assign_vmpck(&dev, 0))
> + return -EINVAL;
> +
> + req.msg_version = MSG_HDR_VER;
> + req.msg_type = SNP_MSG_TSC_INFO_REQ;
> + req.req_buf = &tsc_req;
> + req.req_sz = sizeof(tsc_req);
> + req.resp_buf = buf;
> + req.resp_sz = resp_len;
> + req.fw_err = NULL;
> + req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
> + rc = snp_send_guest_request(&dev, &req);
> + if (rc)
> + goto err_req;
> +
> + memcpy(&tsc_resp, buf, sizeof(tsc_resp));
> + pr_debug("%s: Valid response status %x scale %llx offset %llx factor %llx\n",
> + __func__, tsc_resp.status, tsc_resp.tsc_scale, tsc_resp.tsc_offset,
> + tsc_resp.tsc_factor);
> +
> + guest_tsc_scale = tsc_resp.tsc_scale;
> + guest_tsc_offset = tsc_resp.tsc_offset;
> +
> +err_req:
> + /* The response buffer contains the sensitive data, explicitly clear it. */
> + memzero_explicit(buf, sizeof(buf));
> + memzero_explicit(&tsc_resp, sizeof(tsc_resp));
> + memzero_explicit(&req, sizeof(req));
> +
> + return rc;
> +}
> +
> +bool __init snp_secure_tsc_prepare(void)
> +{
> + platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
> + if (!platform_data)
> + return false;
> +
> + /* Initialize the PSP channel to send snp messages */
> + if (snp_setup_psp_messaging(platform_data))
> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
> +
> + if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
Should this be checked before allocating memory and calling
snp_setup_psp_messaging()?
Also, I notice here you use the cc_platform_has() function but in previous
patches you check sev_status directly. And you don't implement support for
CC_ATTR_GUEST_SECURE_TSC until the last patch instead of now.
You can't get here until SNP_FEATURES_PRESENT is updated.
> + if (snp_get_tsc_info())
> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
> +
> + pr_info("SecureTSC enabled\n");
> + }
Blank line.
Thanks,
Tom
> + return true;
> +}
> +
> static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
> {
> struct sev_es_save_area *cur_vmsa, *vmsa;
> @@ -1506,6 +1584,12 @@ static int wakeup_cpu_via_vmgexit(int apic_id, unsigned long start_ip)
> vmsa->vmpl = 0;
> vmsa->sev_features = sev_status >> 2;
>
> + /* Setting Secure TSC parameters */
> + if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
> + vmsa->tsc_scale = guest_tsc_scale;
> + vmsa->tsc_offset = guest_tsc_offset;
> + }
> +
> /* Switch the page over to a VMSA page now that it is initialized */
> ret = snp_set_vmsa(vmsa, true);
> if (ret) {
> @@ -2698,11 +2782,7 @@ static int __init snp_init_platform_device(void)
> if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
> return -ENODEV;
>
> - platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
> - if (!platform_data)
> - return -ENOMEM;
> -
> - if (snp_setup_psp_messaging(platform_data))
> + if (!platform_data->ctx)
> return -ENODEV;
>
> if (platform_device_add_data(&sev_guest_device, platform_data, sizeof(*platform_data)))
> diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
> index 9c4d8dbcb129..7d2388e52b8f 100644
> --- a/arch/x86/mm/mem_encrypt_amd.c
> +++ b/arch/x86/mm/mem_encrypt_amd.c
> @@ -215,6 +215,11 @@ void __init sme_map_bootdata(char *real_mode_data)
> __sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
> }
>
> +void __init amd_enc_init(void)
> +{
> + snp_secure_tsc_prepare();
> +}
> +
> void __init sev_setup_arch(void)
> {
> phys_addr_t total_mem = memblock_phys_mem_size();
> @@ -501,6 +506,7 @@ void __init sme_early_init(void)
> x86_platform.guest.enc_status_change_finish = amd_enc_status_change_finish;
> x86_platform.guest.enc_tlb_flush_required = amd_enc_tlb_flush_required;
> x86_platform.guest.enc_cache_flush_required = amd_enc_cache_flush_required;
> + x86_platform.guest.enc_init = amd_enc_init;
> }
>
> void __init mem_encrypt_free_decrypted_mem(void)
> diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
> index cb0d6cd1c12f..e081ca4d5da2 100644
> --- a/include/linux/cc_platform.h
> +++ b/include/linux/cc_platform.h
> @@ -90,6 +90,14 @@ enum cc_attr {
> * Examples include TDX Guest.
> */
> CC_ATTR_HOTPLUG_DISABLED,
> +
> + /**
> + * @CC_ATTR_GUEST_SECURE_TSC: Secure TSC is active.
> + *
> + * The platform/OS is running as a guest/virtual machine and actively
> + * using AMD SEV-SNP Secure TSC feature.
> + */
> + CC_ATTR_GUEST_SECURE_TSC,
> };
>
> #ifdef CONFIG_ARCH_HAS_CC_PLATFORM
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-04-03 21:41 ` Tom Lendacky
@ 2023-04-05 7:37 ` Nikunj A. Dadhania
2023-04-05 13:24 ` Tom Lendacky
0 siblings, 1 reply; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 7:37 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 3:11 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> Add support for Secure TSC in SNP enabled guests. Secure TSC
>> allows guest to securely use RDTSC/RDTSCP instructions as the
>> parameters being used cannot be changed by hypervisor once the
>> guest is launched.
>>
>> During the boot-up of the secondary cpus, SecureTSC enabled
>> guests need to query TSC info from Security processor (PSP).
>
> s/Security processor (PSP)/AMD Secure Processor/
>
>> This communication channel is encrypted between the security
>
> here as well.
>
>> processor and the guest, hypervisor is just the conduit to
>
> s/hypervisor/the hypervisor/
>
Sure, will change commit message
>> deliver the guest messages to the security processor. Each
>> message is protected with an AEAD (AES-256 GCM). Use minimal
>> GCM library to encrypt/decrypt SNP Guest messages to communicate
>> with the PSP.
>>
>> Moreover, the hypervisor should not be intercepting RDTSC/RDTSCP
>> when Secure TSC is enabled. A #VC exception will be generated if
>> the RDTSC/RDTSCP instructions are being intercepted. If this should
>> occur and Secure TSC is enabled, terminate guest execution.
>
> This seems like a separate patch.
Sure.
>>
>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>> ---
>> diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
>> index 834cdae302ad..d5ed041ce06b 100644
>> --- a/arch/x86/include/asm/sev-guest.h
>> +++ b/arch/x86/include/asm/sev-guest.h
>> +#define SNP_TSC_INFO_REQ_SZ 128
>> + /* Must be zero filled */
>> + u8 rsvd[SNP_TSC_INFO_REQ_SZ];
>> +} __packed;
>> +
>> +struct snp_tsc_info_resp {
>> + /* Status of TSC_INFO message */
>> + u32 status;
>> + u32 rsvd1;
>> + u64 tsc_scale;
>> + u64 tsc_offset;
>> + u64 tsc_factor;
>
> This should be a u32 ...
>
Right, will correct.
>> + u8 rsvd2[96];
>
> Which then makes this 100.
Yes.
>> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
>> index 3750e545d688..280aaa1e6aad 100644
>> --- a/arch/x86/kernel/sev.c
>> +++ b/arch/x86/kernel/sev.c
>> +bool __init snp_secure_tsc_prepare(void)
>> +{
>> + platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
>> + if (!platform_data)
>> + return false;
>> +
>> + /* Initialize the PSP channel to send snp messages */
>> + if (snp_setup_psp_messaging(platform_data))
>> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
>> +
>> + if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
>
> Should this be checked before allocating memory and calling snp_setup_psp_messaging()?
No, as we need guest messaging to work without Secure TSC as well.
> Also, I notice here you use the cc_platform_has() function but in previous
> patches you check sev_status directly.
For sev-shared.c, cc_platform_has() is not available when compiling boot/compressed.
I will change the below call site to cc_platfrom_has() after testing.
arch/x86/kernel/sev.c: if (regs->cx == MSR_IA32_TSC && (sev_status & MSR_AMD64_SNP_SECURE_TSC)) {
> And you don't implement support for
> CC_ATTR_GUEST_SECURE_TSC until the last patch instead of now.
This is to make sure that SECURE_TSC is enabled only after the last patch.
As cc_platform_has() is being used at multiple places to enable the feature.
> You can't get here until SNP_FEATURES_PRESENT is updated.
>
>> + if (snp_get_tsc_info())
>> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
>> +
>> + pr_info("SecureTSC enabled\n");
>> + }
>
> Blank line.
Sure
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-04-05 7:37 ` Nikunj A. Dadhania
@ 2023-04-05 13:24 ` Tom Lendacky
2023-04-05 14:37 ` Nikunj A. Dadhania
0 siblings, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-05 13:24 UTC (permalink / raw)
To: nikunj, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/5/23 02:37, Nikunj A. Dadhania wrote:
> On 4/4/2023 3:11 AM, Tom Lendacky wrote:
>> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>>> Add support for Secure TSC in SNP enabled guests. Secure TSC
>>> allows guest to securely use RDTSC/RDTSCP instructions as the
>>> parameters being used cannot be changed by hypervisor once the
>>> guest is launched.
>>>
>>> During the boot-up of the secondary cpus, SecureTSC enabled
>>> guests need to query TSC info from Security processor (PSP).
>>
>> s/Security processor (PSP)/AMD Secure Processor/
>>
>>> This communication channel is encrypted between the security
>>
>> here as well.
>>
>>> processor and the guest, hypervisor is just the conduit to
>>
>> s/hypervisor/the hypervisor/
>>
>
> Sure, will change commit message
>
>>> deliver the guest messages to the security processor. Each
>>> message is protected with an AEAD (AES-256 GCM). Use minimal
>>> GCM library to encrypt/decrypt SNP Guest messages to communicate
>>> with the PSP.
>>>
>>> Moreover, the hypervisor should not be intercepting RDTSC/RDTSCP
>>> when Secure TSC is enabled. A #VC exception will be generated if
>>> the RDTSC/RDTSCP instructions are being intercepted. If this should
>>> occur and Secure TSC is enabled, terminate guest execution.
>>
>> This seems like a separate patch.
>
> Sure.
>
>>>
>>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>>> ---
>
>>> diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
>>> index 834cdae302ad..d5ed041ce06b 100644
>>> --- a/arch/x86/include/asm/sev-guest.h
>>> +++ b/arch/x86/include/asm/sev-guest.h
>
>>> +#define SNP_TSC_INFO_REQ_SZ 128
>>> + /* Must be zero filled */
>>> + u8 rsvd[SNP_TSC_INFO_REQ_SZ];
>>> +} __packed;
>>> +
>>> +struct snp_tsc_info_resp {
>>> + /* Status of TSC_INFO message */
>>> + u32 status;
>>> + u32 rsvd1;
>>> + u64 tsc_scale;
>>> + u64 tsc_offset;
>>> + u64 tsc_factor;
>>
>> This should be a u32 ...
>>
>
> Right, will correct.
>
>>> + u8 rsvd2[96];
>>
>> Which then makes this 100.
>
> Yes.
>
>>> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
>>> index 3750e545d688..280aaa1e6aad 100644
>>> --- a/arch/x86/kernel/sev.c
>>> +++ b/arch/x86/kernel/sev.c
>
>>> +bool __init snp_secure_tsc_prepare(void)
>>> +{
>>> + platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
>>> + if (!platform_data)
>>> + return false;
>>> +
>>> + /* Initialize the PSP channel to send snp messages */
>>> + if (snp_setup_psp_messaging(platform_data))
>>> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
>>> +
>>> + if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
>>
>> Should this be checked before allocating memory and calling snp_setup_psp_messaging()?
>
> No, as we need guest messaging to work without Secure TSC as well.
My take is that the sev-guest driver should establish the key it is going
to use at the time the driver is loaded. snp_setup_psp_messaging() should
be called by whatever is going to use guest messaging.
Having a generic routine that is accessed by both the kernel and the
driver should be the goal. Maybe it is best to only have the vmpck_id be
part of any structure and then the appropriate key and sequence number are
used based on that id when the request is made.
The sev_guest_platform_data struct can just hold context information (it
doesn't need the secrets_gpa any more since everything is now in sev.c
which knows what that value is) for whatever is using guest messaging.
>
>
>> Also, I notice here you use the cc_platform_has() function but in previous
>> patches you check sev_status directly.
>
> For sev-shared.c, cc_platform_has() is not available when compiling boot/compressed.
>
> I will change the below call site to cc_platfrom_has() after testing.
>
> arch/x86/kernel/sev.c: if (regs->cx == MSR_IA32_TSC && (sev_status & MSR_AMD64_SNP_SECURE_TSC)) {
>
>> And you don't implement support for
>> CC_ATTR_GUEST_SECURE_TSC until the last patch instead of now.
>
> This is to make sure that SECURE_TSC is enabled only after the last patch.
> As cc_platform_has() is being used at multiple places to enable the feature.
But you terminate long before that in snp_check_features() since you don't
update SNP_FEATURES_PRESENT with SECURE_TSC until the last patch, right?
Thanks,
Tom
>
>> You can't get here until SNP_FEATURES_PRESENT is updated.
>>
>>> + if (snp_get_tsc_info())
>>> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
>>> +
>>> + pr_info("SecureTSC enabled\n");
>>> + }
>>
>> Blank line.
>
> Sure
>
> Regards
> Nikunj
>
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-04-05 13:24 ` Tom Lendacky
@ 2023-04-05 14:37 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 14:37 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/5/2023 6:54 PM, Tom Lendacky wrote:
> On 4/5/23 02:37, Nikunj A. Dadhania wrote:
>> On 4/4/2023 3:11 AM, Tom Lendacky wrote:
>>> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>>>> Add support for Secure TSC in SNP enabled guests. Secure TSC
>>>> allows guest to securely use RDTSC/RDTSCP instructions as the
>>>> parameters being used cannot be changed by hypervisor once the
>>>> guest is launched.
>>>>
>>>> During the boot-up of the secondary cpus, SecureTSC enabled
>>>> guests need to query TSC info from Security processor (PSP).
>>>
>>> s/Security processor (PSP)/AMD Secure Processor/
>>>
>>>> This communication channel is encrypted between the security
>>>
>>> here as well.
>>>
>>>> processor and the guest, hypervisor is just the conduit to
>>>
>>> s/hypervisor/the hypervisor/
>>>
>>
>> Sure, will change commit message
>>
>>>> deliver the guest messages to the security processor. Each
>>>> message is protected with an AEAD (AES-256 GCM). Use minimal
>>>> GCM library to encrypt/decrypt SNP Guest messages to communicate
>>>> with the PSP.
>>>>
>>>> Moreover, the hypervisor should not be intercepting RDTSC/RDTSCP
>>>> when Secure TSC is enabled. A #VC exception will be generated if
>>>> the RDTSC/RDTSCP instructions are being intercepted. If this should
>>>> occur and Secure TSC is enabled, terminate guest execution.
>>>
>>> This seems like a separate patch.
>>
>> Sure.
>>
>>>>
>>>> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
>>>> ---
>>
>>>> diff --git a/arch/x86/include/asm/sev-guest.h b/arch/x86/include/asm/sev-guest.h
>>>> index 834cdae302ad..d5ed041ce06b 100644
>>>> --- a/arch/x86/include/asm/sev-guest.h
>>>> +++ b/arch/x86/include/asm/sev-guest.h
>>
>>>> +#define SNP_TSC_INFO_REQ_SZ 128
>>>> + /* Must be zero filled */
>>>> + u8 rsvd[SNP_TSC_INFO_REQ_SZ];
>>>> +} __packed;
>>>> +
>>>> +struct snp_tsc_info_resp {
>>>> + /* Status of TSC_INFO message */
>>>> + u32 status;
>>>> + u32 rsvd1;
>>>> + u64 tsc_scale;
>>>> + u64 tsc_offset;
>>>> + u64 tsc_factor;
>>>
>>> This should be a u32 ...
>>>
>>
>> Right, will correct.
>>
>>>> + u8 rsvd2[96];
>>>
>>> Which then makes this 100.
>>
>> Yes.
>>
>>>> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
>>>> index 3750e545d688..280aaa1e6aad 100644
>>>> --- a/arch/x86/kernel/sev.c
>>>> +++ b/arch/x86/kernel/sev.c
>>
>>>> +bool __init snp_secure_tsc_prepare(void)
>>>> +{
>>>> + platform_data = kzalloc(sizeof(*platform_data), GFP_KERNEL);
>>>> + if (!platform_data)
>>>> + return false;
>>>> +
>>>> + /* Initialize the PSP channel to send snp messages */
>>>> + if (snp_setup_psp_messaging(platform_data))
>>>> + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
>>>> +
>>>> + if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC)) {
>>>
>>> Should this be checked before allocating memory and calling snp_setup_psp_messaging()?
>>
>> No, as we need guest messaging to work without Secure TSC as well.
>
> My take is that the sev-guest driver should establish the key it is going to use at the time the driver is loaded. > snp_setup_psp_messaging() should be called by whatever is going to use guest messaging.
Should sev-guest also call snp_setup_psp_messaging() ?
As per the current design:
* snp_secure_tsc_prepare populates platform_data (probably I should rename it snp_prepare_psp_messaging)
* In snp_init_platform_device() platform_data is copied using platform_device_add_data().
sev-guest driver in sev_guest_probe() uses this platform_data populated by snp_secure_tsc_prepare().
>
> Having a generic routine that is accessed by both the kernel and the driver should be the goal. Maybe it is best to only have the vmpck_id be part of any structure and then the appropriate key and sequence number are used based on that id when the request is made.
I understand what you are suggesting, let me think over this and I will come back.
> The sev_guest_platform_data struct can just hold context information (it doesn't need the secrets_gpa any more since everything is now in sev.c which knows what that value is) for whatever is using guest messaging.
We are using snp_assign_vmpck() in the sev-guest driver that is dependent on secrets_gpa, we can get rid of that dependency I think.
>>
>>
>>> Also, I notice here you use the cc_platform_has() function but in previous
>>> patches you check sev_status directly.
>>
>> For sev-shared.c, cc_platform_has() is not available when compiling boot/compressed.
>>
>> I will change the below call site to cc_platfrom_has() after testing.
>>
>> arch/x86/kernel/sev.c: if (regs->cx == MSR_IA32_TSC && (sev_status & MSR_AMD64_SNP_SECURE_TSC)) {
>>
>>> And you don't implement support for
>>> CC_ATTR_GUEST_SECURE_TSC until the last patch instead of now.
>>
>> This is to make sure that SECURE_TSC is enabled only after the last patch.
>> As cc_platform_has() is being used at multiple places to enable the feature.
>
> But you terminate long before that in snp_check_features() since you don't update SNP_FEATURES_PRESENT with SECURE_TSC until the last patch, right?
Yes, that correct. I will implement full support for CC_ATTR_GUEST_SECURE_TSC in this patch.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* Re: [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-03-26 14:46 ` [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests Nikunj A Dadhania
2023-04-03 21:41 ` Tom Lendacky
@ 2023-04-10 17:14 ` Peter Gonda
2023-04-14 5:10 ` Nikunj A. Dadhania
1 sibling, 1 reply; 33+ messages in thread
From: Peter Gonda @ 2023-04-10 17:14 UTC (permalink / raw)
To: Nikunj A Dadhania
Cc: linux-kernel, x86, bp, thomas.lendacky, dionnaglaze, seanjc,
pbonzini, michael.roth, ketanch
> +
> /* #VC handler runtime per-CPU data */
> struct sev_es_runtime_data {
> struct ghcb ghcb_page;
> @@ -1107,7 +1111,7 @@ static void *alloc_shared_pages(size_t sz)
> return page_address(page);
> }
>
> -static int snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
> +static int __init snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
> {
> u64 gpa;
> int ret;
> @@ -1406,6 +1410,80 @@ bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
> }
> EXPORT_SYMBOL_GPL(snp_assign_vmpck);
>
> +static int __init snp_get_tsc_info(void)
> +{
> + u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN];
> + struct snp_tsc_info_resp tsc_resp = {0};
> + struct snp_tsc_info_req tsc_req;
> + struct snp_guest_req req;
> + struct snp_guest_dev dev;
> + int rc, resp_len;
> +
> + /*
> + * The intermediate response buffer is used while decrypting the
> + * response payload. Make sure that it has enough space to cover the
> + * authtag.
> + */
> + resp_len = sizeof(tsc_resp) + AUTHTAG_LEN;
> + if (sizeof(buf) < resp_len)
> + return -EINVAL;
> +
> + /* Zero the tsc_info_req */
> + memzero_explicit(&tsc_req, sizeof(tsc_req));
> + memzero_explicit(&req, sizeof(req));
Whats the guidance on when we should use memzero_explicit() vs just
something like: `snp_tsc_info_resp tsc_resp = {0};`?
> +
> + dev.pdata = platform_data;
> + if (!snp_assign_vmpck(&dev, 0))
> + return -EINVAL;
> +
> + req.msg_version = MSG_HDR_VER;
> + req.msg_type = SNP_MSG_TSC_INFO_REQ;
> + req.req_buf = &tsc_req;
> + req.req_sz = sizeof(tsc_req);
> + req.resp_buf = buf;
> + req.resp_sz = resp_len;
> + req.fw_err = NULL;
Why do we not want the FW error code?
> + req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
> + rc = snp_send_guest_request(&dev, &req);
> + if (rc)
> + goto err_req;
> +
> + memcpy(&tsc_resp, buf, sizeof(tsc_resp));
> + pr_debug("%s: Valid response status %x scale %llx offset %llx factor %llx\n",
> + __func__, tsc_resp.status, tsc_resp.tsc_scale, tsc_resp.tsc_offset,
> + tsc_resp.tsc_factor);
> +
> + guest_tsc_scale = tsc_resp.tsc_scale;
> + guest_tsc_offset = tsc_resp.tsc_offset;
> +
> +err_req:
> + /* The response buffer contains the sensitive data, explicitly clear it. */
> + memzero_explicit(buf, sizeof(buf));
> + memzero_explicit(&tsc_resp, sizeof(tsc_resp));
> + memzero_explicit(&req, sizeof(req));
> +
> + return rc;
> +}
> +
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests
2023-04-10 17:14 ` Peter Gonda
@ 2023-04-14 5:10 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-14 5:10 UTC (permalink / raw)
To: Peter Gonda
Cc: linux-kernel, x86, bp, thomas.lendacky, dionnaglaze, seanjc,
pbonzini, michael.roth, ketanch
On 4/10/2023 10:44 PM, Peter Gonda wrote:
>> +
>> /* #VC handler runtime per-CPU data */
>> struct sev_es_runtime_data {
>> struct ghcb ghcb_page;
>> @@ -1107,7 +1111,7 @@ static void *alloc_shared_pages(size_t sz)
>> return page_address(page);
>> }
>>
>> -static int snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
>> +static int __init snp_setup_psp_messaging(struct sev_guest_platform_data *pdata)
>> {
>> u64 gpa;
>> int ret;
>> @@ -1406,6 +1410,80 @@ bool snp_assign_vmpck(struct snp_guest_dev *dev, int vmpck_id)
>> }
>> EXPORT_SYMBOL_GPL(snp_assign_vmpck);
>>
>> +static int __init snp_get_tsc_info(void)
>> +{
>> + u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN];
>> + struct snp_tsc_info_resp tsc_resp = {0};
>> + struct snp_tsc_info_req tsc_req;
>> + struct snp_guest_req req;
>> + struct snp_guest_dev dev;
>> + int rc, resp_len;
>> +
>> + /*
>> + * The intermediate response buffer is used while decrypting the
>> + * response payload. Make sure that it has enough space to cover the
>> + * authtag.
>> + */
>> + resp_len = sizeof(tsc_resp) + AUTHTAG_LEN;
>> + if (sizeof(buf) < resp_len)
>> + return -EINVAL;
>> +
>> + /* Zero the tsc_info_req */
>> + memzero_explicit(&tsc_req, sizeof(tsc_req));
>> + memzero_explicit(&req, sizeof(req));
>
> Whats the guidance on when we should use memzero_explicit() vs just
> something like: `snp_tsc_info_resp tsc_resp = {0};`?
Going over the history of memzero_explicit, it seems it was introduce to
explicitly zero sensitive information before the variable goes out of scope.
GCC was optimizing out the memset in these cases:
d4c5efdb9777 ("random: add and use memzero_explicit() for clearing data")
https://bugzilla.kernel.org/show_bug.cgi?id=82041
With the above detail, IMHO, we do not need the memzero_explicit() for both case.
>
>> +
>> + dev.pdata = platform_data;
>> + if (!snp_assign_vmpck(&dev, 0))
>> + return -EINVAL;
>> +
>> + req.msg_version = MSG_HDR_VER;
>> + req.msg_type = SNP_MSG_TSC_INFO_REQ;
>> + req.req_buf = &tsc_req;
>> + req.req_sz = sizeof(tsc_req);
>> + req.resp_buf = buf;
>> + req.resp_sz = resp_len;
>> + req.fw_err = NULL;
>
> Why do we not want the FW error code?
I will add the FW error code.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (7 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 08/11] x86/sev: Add Secure TSC support for SNP guests Nikunj A Dadhania
@ 2023-03-26 14:46 ` Nikunj A Dadhania
2023-04-03 21:45 ` Tom Lendacky
2023-03-26 14:47 ` [PATCH v2 10/11] x86/tsc: Mark Secure TSC as reliable clocksource Nikunj A Dadhania
2023-03-26 14:47 ` [PATCH v2 11/11] x86/sev: Enable Secure TSC for SNP guests Nikunj A Dadhania
10 siblings, 1 reply; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:46 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
For AMD SNP guests having Secure TSC enabled, use Secure TSC based
clocksource instead of kvmclock.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/kernel/kvmclock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 0f35d44c56fe..1be342064851 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -288,7 +288,7 @@ void __init kvmclock_init(void)
{
u8 flags;
- if (!kvm_para_available() || !kvmclock)
+ if (!kvm_para_available() || !kvmclock || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
return;
if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available
2023-03-26 14:46 ` [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available Nikunj A Dadhania
@ 2023-04-03 21:45 ` Tom Lendacky
2023-04-05 8:16 ` Nikunj A. Dadhania
0 siblings, 1 reply; 33+ messages in thread
From: Tom Lendacky @ 2023-04-03 21:45 UTC (permalink / raw)
To: Nikunj A Dadhania, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 3/26/23 09:46, Nikunj A Dadhania wrote:
> For AMD SNP guests having Secure TSC enabled, use Secure TSC based
> clocksource instead of kvmclock.
This patch only results in skipping the initialization of KVM clock, it
doesn't cause Secure TSC to be used as the clocksource.
Thanks,
Tom
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> arch/x86/kernel/kvmclock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 0f35d44c56fe..1be342064851 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -288,7 +288,7 @@ void __init kvmclock_init(void)
> {
> u8 flags;
>
> - if (!kvm_para_available() || !kvmclock)
> + if (!kvm_para_available() || !kvmclock || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
> return;
>
> if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
^ permalink raw reply [flat|nested] 33+ messages in thread* Re: [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available
2023-04-03 21:45 ` Tom Lendacky
@ 2023-04-05 8:16 ` Nikunj A. Dadhania
0 siblings, 0 replies; 33+ messages in thread
From: Nikunj A. Dadhania @ 2023-04-05 8:16 UTC (permalink / raw)
To: Tom Lendacky, linux-kernel, x86
Cc: bp, dionnaglaze, pgonda, seanjc, pbonzini, michael.roth, ketanch
On 4/4/2023 3:15 AM, Tom Lendacky wrote:
> On 3/26/23 09:46, Nikunj A Dadhania wrote:
>> For AMD SNP guests having Secure TSC enabled, use Secure TSC based
>> clocksource instead of kvmclock.
>
> This patch only results in skipping the initialization of KVM clock, it doesn't cause Secure TSC to be used as the clocksource.
>
Will update the commit message and reorder with 10/11. After making TSC reliable and skipping kvmclock, secure tsc is used as clocksource.
Regards
Nikunj
^ permalink raw reply [flat|nested] 33+ messages in thread
* [PATCH v2 10/11] x86/tsc: Mark Secure TSC as reliable clocksource
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (8 preceding siblings ...)
2023-03-26 14:46 ` [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available Nikunj A Dadhania
@ 2023-03-26 14:47 ` Nikunj A Dadhania
2023-03-26 14:47 ` [PATCH v2 11/11] x86/sev: Enable Secure TSC for SNP guests Nikunj A Dadhania
10 siblings, 0 replies; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:47 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
AMD SNP guests may have Secure TSC feature enabled. Secure TSC as
clocksource is wrongly marked as unstable, mark Secure TSC as
reliable.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/kernel/tsc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 344698852146..5f1e2b51ae3b 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1221,7 +1221,7 @@ static void __init check_system_tsc_reliable(void)
tsc_clocksource_reliable = 1;
}
#endif
- if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
+ if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE) || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
tsc_clocksource_reliable = 1;
/*
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread* [PATCH v2 11/11] x86/sev: Enable Secure TSC for SNP guests
2023-03-26 14:46 [PATCH v2 00/11] Add Secure TSC support for SNP guests Nikunj A Dadhania
` (9 preceding siblings ...)
2023-03-26 14:47 ` [PATCH v2 10/11] x86/tsc: Mark Secure TSC as reliable clocksource Nikunj A Dadhania
@ 2023-03-26 14:47 ` Nikunj A Dadhania
10 siblings, 0 replies; 33+ messages in thread
From: Nikunj A Dadhania @ 2023-03-26 14:47 UTC (permalink / raw)
To: linux-kernel, x86
Cc: bp, thomas.lendacky, dionnaglaze, pgonda, seanjc, pbonzini,
nikunj, michael.roth, ketanch
Now that all the required plumbing is done for enabling SNP
Secure TSC feature, add Secure TSC to snp features present list.
The CC_ATTR_GUEST_SECURE_TSC can be used by the guest to query whether
the SNP guest has Secure TSC feature active.
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/boot/compressed/sev.c | 2 +-
arch/x86/coco/core.c | 3 +++
arch/x86/mm/mem_encrypt.c | 10 ++++++++--
3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index d63ad8f99f83..13b6ff192c3e 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -315,7 +315,7 @@ static void enforce_vmpl0(void)
* by the guest kernel. As and when a new feature is implemented in the
* guest kernel, a corresponding bit should be added to the mask.
*/
-#define SNP_FEATURES_PRESENT (0)
+#define SNP_FEATURES_PRESENT (MSR_AMD64_SNP_SECURE_TSC)
void snp_check_features(void)
{
diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
index 49b44f881484..a3d93ed722c9 100644
--- a/arch/x86/coco/core.c
+++ b/arch/x86/coco/core.c
@@ -68,6 +68,9 @@ static bool amd_cc_platform_has(enum cc_attr attr)
case CC_ATTR_GUEST_SEV_SNP:
return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+ case CC_ATTR_GUEST_SECURE_TSC:
+ return sev_status & MSR_AMD64_SNP_SECURE_TSC;
+
default:
return false;
}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 01abecc9a774..26608b9f2ca7 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -69,8 +69,14 @@ static void print_mem_encrypt_feature_info(void)
pr_cont(" SEV-ES");
/* Secure Nested Paging */
- if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
- pr_cont(" SEV-SNP");
+ if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+ pr_cont(" SEV-SNP\n");
+ pr_cont("SNP Features active: ");
+
+ /* SNP Secure TSC */
+ if (cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
+ pr_cont(" SECURE-TSC");
+ }
pr_cont("\n");
}
--
2.34.1
^ permalink raw reply [flat|nested] 33+ messages in thread