[RFC PATCH 05/31] Add is_sev_enabled() helpers

[Neeraj Upadhyay <Neeraj.Upadhyay@xxxxxxx>]

From: Peter Gonda <pgonda@xxxxxxxxxx>

Add helper functions for guest code to check the status of SEV and
SEV-ES.

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Carlos Bilbao <carlos.bilbao@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Michael Roth <michael.roth@xxxxxxx>
Signed-off-by: Peter Gonda <pgonda@xxxxxxxxxx>
Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@xxxxxxx>
---
 tools/testing/selftests/kvm/include/x86/sev.h   |  4 ++++
 tools/testing/selftests/kvm/lib/x86/sev.c       | 17 +++++++++++++++++
 .../testing/selftests/kvm/x86/sev_smoke_test.c  | 11 +++--------
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/sev.h b/tools/testing/selftests/kvm/include/x86/sev.h
index 0b4411847cbf..437e397ddd29 100644
--- a/tools/testing/selftests/kvm/include/x86/sev.h
+++ b/tools/testing/selftests/kvm/include/x86/sev.h
@@ -147,4 +147,8 @@ static inline void snp_launch_update_data(struct kvm_vm *vm, vm_paddr_t gpa,
 	vm_sev_ioctl(vm, KVM_SEV_SNP_LAUNCH_UPDATE, &update_data);
 }
 
+bool is_sev_enabled(void);
+bool is_sev_es_enabled(void);
+bool is_sev_snp_enabled(void);
+
 #endif /* SELFTEST_KVM_SEV_H */
diff --git a/tools/testing/selftests/kvm/lib/x86/sev.c b/tools/testing/selftests/kvm/lib/x86/sev.c
index dd7ccf0324c5..0c542eae4184 100644
--- a/tools/testing/selftests/kvm/lib/x86/sev.c
+++ b/tools/testing/selftests/kvm/lib/x86/sev.c
@@ -306,3 +306,20 @@ void vm_sev_launch(struct kvm_vm *vm, uint64_t policy, uint8_t *measurement)
 
 	sev_vm_launch_finish(vm);
 }
+
+bool is_sev_enabled(void)
+{
+	return rdmsr(MSR_AMD64_SEV) & MSR_AMD64_SEV_ENABLED;
+}
+
+bool is_sev_es_enabled(void)
+{
+	return is_sev_enabled() &&
+	       rdmsr(MSR_AMD64_SEV) & MSR_AMD64_SEV_ES_ENABLED;
+}
+
+bool is_sev_snp_enabled(void)
+{
+	return is_sev_es_enabled() &&
+		rdmsr(MSR_AMD64_SEV) & MSR_AMD64_SEV_SNP_ENABLED;
+}
diff --git a/tools/testing/selftests/kvm/x86/sev_smoke_test.c b/tools/testing/selftests/kvm/x86/sev_smoke_test.c
index 4fcd0f6290ae..29382dcab18c 100644
--- a/tools/testing/selftests/kvm/x86/sev_smoke_test.c
+++ b/tools/testing/selftests/kvm/x86/sev_smoke_test.c
@@ -18,11 +18,7 @@
 
 static void guest_snp_code(void)
 {
-	uint64_t sev_msr = rdmsr(MSR_AMD64_SEV);
-
-	GUEST_ASSERT(sev_msr & MSR_AMD64_SEV_ENABLED);
-	GUEST_ASSERT(sev_msr & MSR_AMD64_SEV_ES_ENABLED);
-	GUEST_ASSERT(sev_msr & MSR_AMD64_SEV_SNP_ENABLED);
+	GUEST_ASSERT(is_sev_snp_enabled());
 
 	wrmsr(MSR_AMD64_SEV_ES_GHCB, GHCB_MSR_TERM_REQ);
 	VMGEXIT();
@@ -31,8 +27,7 @@ static void guest_snp_code(void)
 static void guest_sev_es_code(void)
 {
 	/* TODO: Check CPUID after GHCB-based hypercall support is added. */
-	GUEST_ASSERT(rdmsr(MSR_AMD64_SEV) & MSR_AMD64_SEV_ENABLED);
-	GUEST_ASSERT(rdmsr(MSR_AMD64_SEV) & MSR_AMD64_SEV_ES_ENABLED);
+	GUEST_ASSERT(is_sev_es_enabled());
 
 	/*
 	 * TODO: Add GHCB and ucall support for SEV-ES guests.  For now, simply
@@ -45,7 +40,7 @@ static void guest_sev_es_code(void)
 static void guest_sev_code(void)
 {
 	GUEST_ASSERT(this_cpu_has(X86_FEATURE_SEV));
-	GUEST_ASSERT(rdmsr(MSR_AMD64_SEV) & MSR_AMD64_SEV_ENABLED);
+	GUEST_ASSERT(is_sev_enabled());
 
 	GUEST_DONE();
 }
-- 
2.34.1