[PATCH v7 1/4] crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL

[Dionna Glaze <dionnaglaze@google.com>]

From: Peter Gonda <pgonda@google.com>

The PSP can return a "firmware error" code of -1 in circumstances where
the PSP is not actually called. To make this protocol unambiguous, we
add a constant naming the return value.

Cc: Thomas Lendacky <Thomas.Lendacky@amd.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: John Allen <john.allen@amd.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>

Signed-off-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
---
 drivers/crypto/ccp/sev-dev.c | 2 +-
 include/uapi/linux/psp-sev.h | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 06fc7156c04f..97eb3544ab36 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -444,7 +444,7 @@ static int __sev_platform_init_locked(int *error)
 {
 	struct psp_device *psp = psp_master;
 	struct sev_device *sev;
-	int rc = 0, psp_ret = -1;
+	int rc = 0, psp_ret = SEV_RET_NO_FW_CALL;
 	int (*init_function)(int *error);
 
 	if (!psp || !psp->sev_data)
diff --git a/include/uapi/linux/psp-sev.h b/include/uapi/linux/psp-sev.h
index 91b4c63d5cbf..1ad7f0a7e328 100644
--- a/include/uapi/linux/psp-sev.h
+++ b/include/uapi/linux/psp-sev.h
@@ -36,6 +36,13 @@ enum {
  * SEV Firmware status code
  */
 typedef enum {
+	/*
+	 * This error code is not in the SEV spec but is added to convey that
+	 * there was an error that prevented the SEV Firmware from being called.
+	 * This is (u32)-1 since the firmware error code is represented as a
+	 * 32-bit integer.
+	 */
+	SEV_RET_NO_FW_CALL = 0xffffffff,
 	SEV_RET_SUCCESS = 0,
 	SEV_RET_INVALID_PLATFORM_STATE,
 	SEV_RET_INVALID_GUEST_STATE,
-- 
2.38.1.431.g37b22c650d-goog