[PATCH v6 3/9] KVM: selftests: SEV-SNP test for KVM_SEV_INIT2

Pratik R. Sampat
2025-02-03T22:33:02Z

Add the X86_FEATURE_SEV_SNP CPU feature to the architectural definition
for the SEV-SNP VM type to exercise the KVM_SEV_INIT2 call. Ensure that
the SNP test is skipped in scenarios where CPUID supports it but KVM
does not, preventing reporting of failure in such cases.

Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Tested-by: Srikanth Aithal <sraithal@amd.com>
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
---
v5..v6:

* Rename KVM CPU feature X86_FEATURE_SNP to X86_FEATURE_SEV_SNP (Nikunj)
* Collected tags from Nikunj and Srikanth.
---
tools/testing/selftests/kvm/include/x86/processor.h | 1 +
tools/testing/selftests/kvm/x86/sev_init2_tests.c | 13 +++++++++++++
2 files changed, 14 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
index d60da8966772..6f63fd10bbc6 100644
--- a/tools/testing/selftests/kvm/include/x86/processor.h
+++ b/tools/testing/selftests/kvm/include/x86/processor.h
@@ -199,6 +199,7 @@ struct kvm_x86_cpu_feature {
#define X86_FEATURE_VGIF KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 16)
#define X86_FEATURE_SEV KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 1)
#define X86_FEATURE_SEV_ES KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 3)
+#define X86_FEATURE_SEV_SNP KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 4)

/*
* KVM defined paravirt features.
diff --git a/tools/testing/selftests/kvm/x86/sev_init2_tests.c b/tools/testing/selftests/kvm/x86/sev_init2_tests.c
index 3fb967f40c6a..ab3dd11ac163 100644
--- a/tools/testing/selftests/kvm/x86/sev_init2_tests.c
+++ b/tools/testing/selftests/kvm/x86/sev_init2_tests.c
@@ -28,6 +28,7 @@
int kvm_fd;
u64 supported_vmsa_features;
bool have_sev_es;
+bool have_snp;

static int __sev_ioctl(int vm_fd, int cmd_id, void *data)
{
@@ -83,6 +84,9 @@ void test_vm_types(void)
if (have_sev_es)
test_init2(KVM_X86_SEV_ES_VM, &(struct kvm_sev_init){});

+ if (have_snp)
+ test_init2(KVM_X86_SNP_VM, &(struct kvm_sev_init){});
+
test_init2_invalid(0, &(struct kvm_sev_init){},
"VM type is KVM_X86_DEFAULT_VM");
if (kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM))
@@ -138,15 +142,24 @@ int main(int argc, char *argv[])
"sev-es: KVM_CAP_VM_TYPES (%x) does not match cpuid (checking %x)",
kvm_check_cap(KVM_CAP_VM_TYPES), 1 << KVM_X86_SEV_ES_VM);

+ have_snp = kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SNP_VM);
+ TEST_ASSERT(!have_snp || kvm_cpu_has(X86_FEATURE_SEV_SNP),
+ "sev-snp: KVM_CAP_VM_TYPES (%x) indicates SNP support (bit %d), but CPUID does not",
+ kvm_check_cap(KVM_CAP_VM_TYPES), KVM_X86_SNP_VM);
+
test_vm_types();

test_flags(KVM_X86_SEV_VM);
if (have_sev_es)
test_flags(KVM_X86_SEV_ES_VM);
+ if (have_snp)
+ test_flags(KVM_X86_SNP_VM);

test_features(KVM_X86_SEV_VM, 0);
if (have_sev_es)
test_features(KVM_X86_SEV_ES_VM, supported_vmsa_features);
+ if (have_snp)
+ test_features(KVM_X86_SNP_VM, supported_vmsa_features);

return 0;
}
--
2.43.0