[PATCH v4 0/6] arm64: hyperv: Add Realm support for Hyper-V

[PATCH v4 0/6] arm64: hyperv: Add Realm support for Hyper-V

[Kameron Carr]

Realms (CoCo VMs on ARM) require host calls to be routed through the RMM
(Realm Management Monitor) via the RSI (Realm Service Interface). This
series implements most of the necessary changes to support Realms on
Hyper-V.

One required change is not included in this series. The two buffers
allocated via vzalloc() in netvsc_init_buf() cannot be decrypted in
vmbus_establish_gpadl(). Currently only linearly mapped memory can be
decrypted.

This patch series was tested by booting a Realm on Cobalt 200 running
Windows. I tested 4KB and 64KB page size. I replaced vzalloc() in
netvsc_init_buf() with alloc_pages_node() -> set_memory_decrypted() ->
vmap() in my testing as a workaround for the issue mentioned above [1].

Changes since v1 [2]:
  Patch 1: Add explicit padding to the RSI host call structure
  Patch 3: Change from a per-cpu pointer lazily allocated to an array
             of host call structs indexed by cpu id
  Patch 4: Align input_page + output_page allocation to PAGE_SIZE since
             that is the smallest unit of memory that can be decrypted
           ~Remove KASAN tags before passing address to
             set_memory_decrypted() since __is_lm_address() does pointer
             arithmetic.~
  Patch 5: Add a helper function to reduce repetition
           Check for NULL before indexing into host call array

Changes since v2 [3]:
  Patch 3: Remove hv_hostcall_free() and inline the logic for simplicity
           Reorder edits to keep #include line at the end of the file
  Patch 4: Remove kasan_reset_tag()

Changes since v3 [4]:
  Rebased onto arm64 for-next/smccc-bus which includes moving RSI header
  files out of arch/arm64 [5]

[1] https://lore.kernel.org/all/20260721195633.1438361-1-kameroncarr@linux.microsoft.com/
[2] https://lore.kernel.org/all/20260609181030.2378391-1-kameroncarr@linux.microsoft.com/
[3] https://lore.kernel.org/all/20260625173500.1995481-1-kameroncarr@linux.microsoft.com/
[4] https://lore.kernel.org/all/20260721201148.1441143-1-kameroncarr@linux.microsoft.com/
[5] https://lore.kernel.org/all/20260923140405.1111554-4-aneesh.kumar@kernel.org/

Kameron Carr (6):
  arm64: rsi: Add RSI host call structure and helper function
  firmware: smccc: Detect hypervisor via RSI host call in CCA Realms
  arm64: hyperv: Add per-CPU RSI host call infrastructure for CCA Realms
  Drivers: hv: Mark shared memory as decrypted for CCA Realms
  arm64: hyperv: Route hypercalls through RSI host call in CCA Realms
  arm64: hyperv: Implement hv_is_isolation_supported() for CCA Realms

 arch/arm64/hyperv/hv_core.c       | 156 +++++++++++++++++++++++-------
 arch/arm64/hyperv/mshyperv.c      |  38 +++++++-
 arch/arm64/include/asm/mshyperv.h |   4 +
 drivers/firmware/smccc/smccc.c    |  41 +++++++-
 drivers/hv/hv_common.c            |  17 +++-
 include/asm-generic/mshyperv.h    |   1 +
 include/linux/arm-rsi-cmds.h      |  22 +++++
 include/linux/arm-smccc-rsi.h     |   7 ++
 8 files changed, 245 insertions(+), 41 deletions(-)


base-commit: bce57945f5e7207960b2bd567a6e880f90258ffb
-- 
2.45.4

[PATCH v4 1/6] arm64: rsi: Add RSI host call structure and helper function

[Kameron Carr]

Add struct rsi_host_call to rsi_smc.h, which represents the host call
data structure used by the Realm Management Monitor (RMM) for the
RSI_HOST_CALL interface. The structure contains a 16-bit immediate field
and 31 general-purpose register values, aligned to 256 bytes as required
by the CCA RMM specification.

Add rsi_host_call() static inline wrapper in rsi_cmds.h that invokes
SMC_RSI_HOST_CALL with the physical address of the host call structure.
This will be used by Hyper-V guest code to route hypercalls through the
RSI interface when running inside an Arm CCA Realm.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Kameron Carr <kameroncarr@linux.microsoft.com>
---
 include/linux/arm-rsi-cmds.h  | 22 ++++++++++++++++++++++
 include/linux/arm-smccc-rsi.h |  7 +++++++
 2 files changed, 29 insertions(+)

diff --git a/include/linux/arm-rsi-cmds.h b/include/linux/arm-rsi-cmds.h
index 3f7a6a8..01d292e 100644
--- a/include/linux/arm-rsi-cmds.h
+++ b/include/linux/arm-rsi-cmds.h
@@ -236,4 +236,26 @@ static inline unsigned long rsi_attestation_token_continue(phys_addr_t granule,
 	return res.a0;
 }
 
+/**
+ * rsi_host_call - Make a Host call.
+ * @host_call_struct: IPA of host call structure
+ *
+ * This call will fail if the IPA of the host call structure:
+ * * is not aligned to 256 bytes,
+ * * is not protected / encrypted,
+ * * is RIPAS_EMPTY
+ *
+ * Returns:
+ *  On success, returns RSI_SUCCESS.
+ *  Otherwise, returns an error code.
+ */
+static inline unsigned long rsi_host_call(phys_addr_t host_call_struct)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(SMC_RSI_HOST_CALL, host_call_struct, 0, 0, 0, 0, 0, 0,
+		      &res);
+	return res.a0;
+}
+
 #endif /* __LINUX_ARM_RSI_CMDS_H_ */
diff --git a/include/linux/arm-smccc-rsi.h b/include/linux/arm-smccc-rsi.h
index fddb779..4c8530b 100644
--- a/include/linux/arm-smccc-rsi.h
+++ b/include/linux/arm-smccc-rsi.h
@@ -142,6 +142,13 @@ struct realm_config {
 	 */
 } __aligned(0x1000);
 
+struct rsi_host_call {
+	u16 immediate;
+	u8 _padding[6];
+	u64 gprs[31];
+} __aligned(256);
+static_assert(sizeof(struct rsi_host_call) == 256);
+
 #endif /* __ASSEMBLER__ */
 
 /*
-- 
2.45.4

[PATCH v4 2/6] firmware: smccc: Detect hypervisor via RSI host call in CCA Realms

[Kameron Carr]

Modify arm_smccc_hypervisor_has_uuid() to check is_realm_world() and
use rsi_host_call() to query the hypervisor vendor UUID when inside a
Realm. The realm path is factored into a helper,
arm_smccc_realm_get_hypervisor_uuid(), that owns a file-static
rsi_host_call buffer (uuid_hc) serialized by a spinlock.

The RSI-specific includes, file-static state and helper are guarded
with CONFIG_ARM64 because <asm/rsi.h> does not exist on 32-bit ARM.

For non-Realm environments, the existing arm_smccc_1_1_invoke() path
is unchanged.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Kameron Carr <kameroncarr@linux.microsoft.com>
---
 drivers/firmware/smccc/smccc.c | 41 +++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/smccc/smccc.c b/drivers/firmware/smccc/smccc.c
index afc2e4d..7e77170 100644
--- a/drivers/firmware/smccc/smccc.c
+++ b/drivers/firmware/smccc/smccc.c
@@ -14,6 +14,12 @@
 
 #include <asm/archrandom.h>
 
+#ifdef CONFIG_ARM64
+#include <linux/arm-rsi-cmds.h>
+#include <linux/cleanup.h>
+#include <linux/spinlock.h>
+#endif
+
 static u32 smccc_version = ARM_SMCCC_VERSION_1_0;
 static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE;
 
@@ -69,12 +75,45 @@ s32 arm_smccc_get_soc_id_revision(void)
 }
 EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_revision);
 
+#ifdef CONFIG_ARM64
+static struct rsi_host_call uuid_hc;
+static DEFINE_SPINLOCK(uuid_hc_lock);
+
+/*
+ * Helper function to get the hypervisor UUID via an RsiHostCall.
+ */
+static void arm_smccc_realm_get_hypervisor_uuid(struct arm_smccc_res *res)
+{
+	guard(spinlock_irqsave)(&uuid_hc_lock);
+
+	memset(&uuid_hc, 0, sizeof(uuid_hc));
+	uuid_hc.gprs[0] = ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID;
+
+	if (rsi_host_call(__pa_symbol(&uuid_hc)) != RSI_SUCCESS) {
+		res->a0 = SMCCC_RET_NOT_SUPPORTED;
+		return;
+	}
+
+	res->a0 = uuid_hc.gprs[0];
+	res->a1 = uuid_hc.gprs[1];
+	res->a2 = uuid_hc.gprs[2];
+	res->a3 = uuid_hc.gprs[3];
+}
+#endif
+
 bool arm_smccc_hypervisor_has_uuid(const uuid_t *hyp_uuid)
 {
 	struct arm_smccc_res res = {};
 	uuid_t uuid;
 
-	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+#ifdef CONFIG_ARM64
+	if (is_realm_world())
+		arm_smccc_realm_get_hypervisor_uuid(&res);
+	else
+#endif
+		arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID,
+				     &res);
+
 	if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
 		return false;
 
-- 
2.45.4

[PATCH v4 3/6] arm64: hyperv: Add per-CPU RSI host call infrastructure for CCA Realms

[Kameron Carr]

Arm CCA Realms cannot issue Hyper-V hypercalls via HVC; the guest must
route them through the RSI_HOST_CALL interface, which takes the IPA of a
per-CPU rsi_host_call structure as its argument.

Add hv_hostcall_array as a per-CPU struct array and allocate it during
hyperv_init(). The allocation is gated on is_realm_world() so non-Realm
arm64 Hyper-V guests pay no memory cost.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Kameron Carr <kameroncarr@linux.microsoft.com>
---
 arch/arm64/hyperv/mshyperv.c      | 28 ++++++++++++++++++++++++++--
 arch/arm64/include/asm/mshyperv.h |  4 ++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index 4fdc26a..b1657cf 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -11,14 +11,19 @@
 
 #include <linux/types.h>
 #include <linux/acpi.h>
+#include <linux/arm-rsi-cmds.h>
 #include <linux/export.h>
 #include <linux/errno.h>
+#include <linux/slab.h>
 #include <linux/version.h>
 #include <linux/cpuhotplug.h>
 #include <asm/mshyperv.h>
 
 static bool hyperv_initialized;
 
+struct rsi_host_call *hv_hostcall_array;
+EXPORT_SYMBOL_GPL(hv_hostcall_array);
+
 int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
 {
 	hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION,
@@ -85,6 +90,20 @@ static int __init hyperv_init(void)
 	if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc())
 		return 0;
 
+	/*
+	 * The RSI host-call buffers are only ever used when
+	 * is_realm_world() is true. Skip the allocation on non-Realm
+	 * guests. A single contiguous array of nr_cpu_ids entries is
+	 * allocated; each CPU indexes into it by its processor ID.
+	 */
+	if (is_realm_world()) {
+		hv_hostcall_array = kcalloc(nr_cpu_ids,
+					    sizeof(struct rsi_host_call),
+					    GFP_KERNEL);
+		if (!hv_hostcall_array)
+			return -ENOMEM;
+	}
+
 	/* Setup the guest ID */
 	guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
 	hv_set_vpreg(HV_REGISTER_GUEST_OS_ID, guest_id);
@@ -106,13 +125,13 @@ static int __init hyperv_init(void)
 
 	ret = hv_common_init();
 	if (ret)
-		return ret;
+		goto free_hostcall_mem;
 
 	ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online",
 				hv_common_cpu_init, hv_common_cpu_die);
 	if (ret < 0) {
 		hv_common_free();
-		return ret;
+		goto free_hostcall_mem;
 	}
 
 	if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
@@ -125,6 +144,11 @@ static int __init hyperv_init(void)
 
 	hyperv_initialized = true;
 	return 0;
+
+free_hostcall_mem:
+	kfree(hv_hostcall_array);
+	hv_hostcall_array = NULL;
+	return ret;
 }
 
 early_initcall(hyperv_init);
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index b721d31..aed0aa5 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -61,6 +61,10 @@ static inline u64 hv_get_non_nested_msr(unsigned int reg)
 				ARM_SMCCC_OWNER_VENDOR_HYP,	\
 				HV_SMCCC_FUNC_NUMBER)
 
+/* Per-CPU-indexed RSI host call structures for CCA Realms */
+struct rsi_host_call;
+extern struct rsi_host_call *hv_hostcall_array;
+
 #include <asm-generic/mshyperv.h>
 
 #endif
-- 
2.45.4

[PATCH v4 4/6] Drivers: hv: Mark shared memory as decrypted for CCA Realms

[Kameron Carr]

In hv_common_cpu_init(), the per-CPU hypercall input/output pages need
to be marked as decrypted (shared) for confidential VM isolation types.
This is already done for SNP and TDX isolation; extend the same handling
to Arm CCA Realm guests so that the host hypervisor can access the
shared hypercall buffers.

is_realm_world() is only declared in arch/arm64/include/asm/rsi.h, so
using it directly in the arch-neutral drivers/hv/hv_common.c would
break the x86 build. Introduce a Hyper-V-specific helper following the
established hv_isolation_type_snp() / hv_isolation_type_tdx() pattern.

On architectures other than arm64 the weak default keeps the existing
behaviour.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Kameron Carr <kameroncarr@linux.microsoft.com>
---
 arch/arm64/hyperv/mshyperv.c   |  5 +++++
 drivers/hv/hv_common.c         | 17 +++++++++++++----
 include/asm-generic/mshyperv.h |  1 +
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index b1657cf..45ca8e2 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -158,3 +158,8 @@ bool hv_is_hyperv_initialized(void)
 	return hyperv_initialized;
 }
 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
+
+bool hv_isolation_type_cca(void)
+{
+	return is_realm_world();
+}
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 31256cb..a60c92c 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -476,6 +476,7 @@ int hv_common_cpu_init(unsigned int cpu)
 	u64 msr_vp_index;
 	gfp_t flags;
 	const int pgcount = hv_output_page_exists() ? 2 : 1;
+	const size_t alloc_size = ALIGN((size_t)pgcount * HV_HYP_PAGE_SIZE, PAGE_SIZE);
 	void *mem;
 	int ret = 0;
 
@@ -489,7 +490,7 @@ int hv_common_cpu_init(unsigned int cpu)
 	 * online and then taken offline
 	 */
 	if (!*inputarg) {
-		mem = kmalloc_array(pgcount, HV_HYP_PAGE_SIZE, flags);
+		mem = kmalloc(alloc_size, flags);
 		if (!mem)
 			return -ENOMEM;
 
@@ -499,14 +500,16 @@ int hv_common_cpu_init(unsigned int cpu)
 		}
 
 		if (!ms_hyperv.paravisor_present &&
-		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
-			ret = set_memory_decrypted((unsigned long)mem, pgcount);
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx() ||
+		     hv_isolation_type_cca())) {
+			ret = set_memory_decrypted((unsigned long)mem,
+						   alloc_size >> PAGE_SHIFT);
 			if (ret) {
 				/* It may be unsafe to free 'mem' */
 				return ret;
 			}
 
-			memset(mem, 0x00, pgcount * HV_HYP_PAGE_SIZE);
+			memset(mem, 0x00, alloc_size);
 		}
 
 		/*
@@ -666,6 +669,12 @@ bool __weak hv_isolation_type_tdx(void)
 }
 EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
 
+bool __weak hv_isolation_type_cca(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_cca);
+
 void __weak hv_setup_vmbus_handler(void (*handler)(void))
 {
 }
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index bf601d6..1fa79ab 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -79,6 +79,7 @@ u64 hv_do_fast_hypercall16(u16 control, u64 input1, u64 input2);
 
 bool hv_isolation_type_snp(void);
 bool hv_isolation_type_tdx(void);
+bool hv_isolation_type_cca(void);
 
 /*
  * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
-- 
2.45.4

[PATCH v4 5/6] arm64: hyperv: Route hypercalls through RSI host call in CCA Realms

[Kameron Carr]

Modify the five hypercall wrapper functions to check is_realm_world()
and use the per-CPU rsi_host_call structure when inside a Realm.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Kameron Carr <kameroncarr@linux.microsoft.com>
---
 arch/arm64/hyperv/hv_core.c | 156 ++++++++++++++++++++++++++++--------
 1 file changed, 122 insertions(+), 34 deletions(-)

diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c
index e33a9e3..0b5c89e 100644
--- a/arch/arm64/hyperv/hv_core.c
+++ b/arch/arm64/hyperv/hv_core.c
@@ -12,11 +12,44 @@
 #include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/arm-smccc.h>
+#include <linux/arm-rsi-cmds.h>
 #include <linux/module.h>
+#include <linux/smp.h>
 #include <asm-generic/bug.h>
 #include <hyperv/hvhdk.h>
 #include <asm/mshyperv.h>
 
+
+/*
+ * hv_do_rsi_hypercall - Helper function to invoke a hypercall from a
+ * Realm world using the RSI interface.
+ */
+static u64 hv_do_rsi_hypercall(u64 control, u64 input1, u64 input2)
+{
+	struct rsi_host_call *hostcall;
+	unsigned long flags;
+	u64 ret;
+
+	if (!hv_hostcall_array)
+		return HV_STATUS_INVALID_HYPERCALL_INPUT;
+
+	local_irq_save(flags);
+	hostcall = &hv_hostcall_array[smp_processor_id()];
+	memset(hostcall, 0, sizeof(*hostcall));
+	hostcall->gprs[0] = HV_FUNC_ID;
+	hostcall->gprs[1] = control;
+	hostcall->gprs[2] = input1;
+	hostcall->gprs[3] = input2;
+
+	if (rsi_host_call(virt_to_phys(hostcall)) == RSI_SUCCESS)
+		ret = hostcall->gprs[0];
+	else
+		ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
+
+	local_irq_restore(flags);
+	return ret;
+}
+
 /*
  * hv_do_hypercall- Invoke the specified hypercall
  */
@@ -29,8 +62,11 @@ u64 hv_do_hypercall(u64 control, void *input, void *output)
 	input_address = input ? virt_to_phys(input) : 0;
 	output_address = output ? virt_to_phys(output) : 0;
 
-	arm_smccc_1_1_hvc(HV_FUNC_ID, control,
-			  input_address, output_address, &res);
+	if (is_realm_world())
+		return hv_do_rsi_hypercall(control, input_address, output_address);
+
+	arm_smccc_1_1_hvc(HV_FUNC_ID, control, input_address,
+			  output_address, &res);
 	return res.a0;
 }
 EXPORT_SYMBOL_GPL(hv_do_hypercall);
@@ -48,6 +84,9 @@ u64 hv_do_fast_hypercall8(u16 code, u64 input)
 
 	control = (u64)code | HV_HYPERCALL_FAST_BIT;
 
+	if (is_realm_world())
+		return hv_do_rsi_hypercall(control, input, 0);
+
 	arm_smccc_1_1_hvc(HV_FUNC_ID, control, input, &res);
 	return res.a0;
 }
@@ -65,6 +104,9 @@ u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
 
 	control = (u64)code | HV_HYPERCALL_FAST_BIT;
 
+	if (is_realm_world())
+		return hv_do_rsi_hypercall(control, input1, input2);
+
 	arm_smccc_1_1_hvc(HV_FUNC_ID, control, input1, input2, &res);
 	return res.a0;
 }
@@ -76,24 +118,44 @@ EXPORT_SYMBOL_GPL(hv_do_fast_hypercall16);
 void hv_set_vpreg(u32 msr, u64 value)
 {
 	struct arm_smccc_res res;
+	struct rsi_host_call *hostcall;
+	unsigned long flags;
+	u64 status;
 
-	arm_smccc_1_1_hvc(HV_FUNC_ID,
-		HVCALL_SET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
-			HV_HYPERCALL_REP_COMP_1,
-		HV_PARTITION_ID_SELF,
-		HV_VP_INDEX_SELF,
-		msr,
-		0,
-		value,
-		0,
-		&res);
+	if (is_realm_world()) {
+		local_irq_save(flags);
+		hostcall = &hv_hostcall_array[smp_processor_id()];
+		memset(hostcall, 0, sizeof(*hostcall));
+		hostcall->gprs[0] = HV_FUNC_ID;
+		hostcall->gprs[1] = HVCALL_SET_VP_REGISTERS |
+				    HV_HYPERCALL_FAST_BIT |
+				    HV_HYPERCALL_REP_COMP_1;
+		hostcall->gprs[2] = HV_PARTITION_ID_SELF;
+		hostcall->gprs[3] = HV_VP_INDEX_SELF;
+		hostcall->gprs[4] = msr;
+		hostcall->gprs[6] = value;
+
+		if (rsi_host_call(virt_to_phys(hostcall)) == RSI_SUCCESS)
+			status = hostcall->gprs[0];
+		else
+			status = HV_STATUS_INVALID_HYPERCALL_INPUT;
+		local_irq_restore(flags);
+	} else {
+		arm_smccc_1_1_hvc(HV_FUNC_ID,
+				  HVCALL_SET_VP_REGISTERS |
+					  HV_HYPERCALL_FAST_BIT |
+					  HV_HYPERCALL_REP_COMP_1,
+				  HV_PARTITION_ID_SELF, HV_VP_INDEX_SELF, msr,
+				  0, value, 0, &res);
+		status = res.a0;
+	}
 
 	/*
-	 * Something is fundamentally broken in the hypervisor if
-	 * setting a VP register fails. There's really no way to
-	 * continue as a guest VM, so panic.
+	 * Something is fundamentally broken in the hypervisor (or, in a
+	 * Realm, the RMM denied the host call) if setting a VP register
+	 * fails. There's really no way to continue as a guest VM, so panic.
 	 */
-	BUG_ON(!hv_result_success(res.a0));
+	BUG_ON(!hv_result_success(status));
 }
 EXPORT_SYMBOL_GPL(hv_set_vpreg);
 
@@ -108,29 +170,55 @@ void hv_get_vpreg_128(u32 msr, struct hv_get_vp_registers_output *result)
 {
 	struct arm_smccc_1_2_regs args;
 	struct arm_smccc_1_2_regs res;
+	struct rsi_host_call *hostcall;
+	unsigned long flags;
+	u64 status;
 
-	args.a0 = HV_FUNC_ID;
-	args.a1 = HVCALL_GET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
-			HV_HYPERCALL_REP_COMP_1;
-	args.a2 = HV_PARTITION_ID_SELF;
-	args.a3 = HV_VP_INDEX_SELF;
-	args.a4 = msr;
+	if (is_realm_world()) {
+		local_irq_save(flags);
+		hostcall = &hv_hostcall_array[smp_processor_id()];
+		memset(hostcall, 0, sizeof(*hostcall));
 
-	/*
-	 * Use the SMCCC 1.2 interface because the results are in registers
-	 * beyond X0-X3.
-	 */
-	arm_smccc_1_2_hvc(&args, &res);
+		hostcall->gprs[0] = HV_FUNC_ID;
+		hostcall->gprs[1] = HVCALL_GET_VP_REGISTERS |
+				    HV_HYPERCALL_FAST_BIT |
+				    HV_HYPERCALL_REP_COMP_1;
+		hostcall->gprs[2] = HV_PARTITION_ID_SELF;
+		hostcall->gprs[3] = HV_VP_INDEX_SELF;
+		hostcall->gprs[4] = msr;
+
+		if (rsi_host_call(virt_to_phys(hostcall)) == RSI_SUCCESS) {
+			status = hostcall->gprs[0];
+			result->as64.low = hostcall->gprs[6];
+			result->as64.high = hostcall->gprs[7];
+		} else {
+			status = HV_STATUS_INVALID_HYPERCALL_INPUT;
+		}
+		local_irq_restore(flags);
+	} else {
+		args.a0 = HV_FUNC_ID;
+		args.a1 = HVCALL_GET_VP_REGISTERS | HV_HYPERCALL_FAST_BIT |
+			  HV_HYPERCALL_REP_COMP_1;
+		args.a2 = HV_PARTITION_ID_SELF;
+		args.a3 = HV_VP_INDEX_SELF;
+		args.a4 = msr;
+
+		/*
+		 * Use the SMCCC 1.2 interface because the results are in
+		 * registers beyond X0-X3.
+		 */
+		arm_smccc_1_2_hvc(&args, &res);
+		status = res.a0;
+		result->as64.low = res.a6;
+		result->as64.high = res.a7;
+	}
 
 	/*
-	 * Something is fundamentally broken in the hypervisor if
-	 * getting a VP register fails. There's really no way to
-	 * continue as a guest VM, so panic.
+	 * Something is fundamentally broken in the hypervisor (or, in a
+	 * Realm, the RMM denied the host call) if getting a VP register
+	 * fails. There's really no way to continue as a guest VM, so panic.
 	 */
-	BUG_ON(!hv_result_success(res.a0));
-
-	result->as64.low = res.a6;
-	result->as64.high = res.a7;
+	BUG_ON(!hv_result_success(status));
 }
 EXPORT_SYMBOL_GPL(hv_get_vpreg_128);
 
-- 
2.45.4

[PATCH v4 6/6] arm64: hyperv: Implement hv_is_isolation_supported() for CCA Realms

[Kameron Carr]

Provide an arm64 implementation of hv_is_isolation_supported() that
overrides the __weak default in drivers/hv/hv_common.c.

The implementation deliberately does not depend on
hv_is_hyperv_initialized() because hv_common_init() consults
hv_is_isolation_supported() before hyperv_initialized is set.

Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Kameron Carr <kameroncarr@linux.microsoft.com>
---
 arch/arm64/hyperv/mshyperv.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c
index 45ca8e2..c41188a 100644
--- a/arch/arm64/hyperv/mshyperv.c
+++ b/arch/arm64/hyperv/mshyperv.c
@@ -163,3 +163,8 @@ bool hv_isolation_type_cca(void)
 {
 	return is_realm_world();
 }
+
+bool hv_is_isolation_supported(void)
+{
+	return is_realm_world();
+}
-- 
2.45.4