[PATCH v8 10/10] KVM: selftests: Add a basic SEV-SNP smoke test

[Pratik R. Sampat]

Extend sev_smoke_test to also run a minimal SEV-SNP smoke test that
initializes and sets up private memory regions required to run a simple
SEV-SNP guest.

Similar to its SEV-ES smoke test counterpart, this also does not
support GHCB and ucall yet and uses the GHCB MSR protocol to trigger an
exit of the type KVM_EXIT_SYSTEM_EVENT.

Signed-off-by: Pratik R. Sampat <prsam...@amd.com>
---
 .../selftests/kvm/x86/sev_smoke_test.c        | 25 +++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86/sev_smoke_test.c 
b/tools/testing/selftests/kvm/x86/sev_smoke_test.c
index 620aa7c41f7a..0505cde77358 100644
--- a/tools/testing/selftests/kvm/x86/sev_smoke_test.c
+++ b/tools/testing/selftests/kvm/x86/sev_smoke_test.c
@@ -16,6 +16,18 @@
 
 #define XFEATURE_MASK_X87_AVX (XFEATURE_MASK_FP | XFEATURE_MASK_SSE | 
XFEATURE_MASK_YMM)
 
+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);
+
+       wrmsr(MSR_AMD64_SEV_ES_GHCB, GHCB_MSR_TERM_REQ);
+       vmgexit();
+}
+
 static void guest_sev_es_code(void)
 {
        /* TODO: Check CPUID after GHCB-based hypercall support is added. */
@@ -179,7 +191,10 @@ static void test_sev_smoke(void *guest, uint32_t type, 
uint64_t policy)
 {
        const u64 xf_mask = XFEATURE_MASK_X87_AVX;
 
-       test_sev(guest, type, policy | SEV_POLICY_NO_DBG);
+       if (type == KVM_X86_SNP_VM)
+               test_sev(guest, type, policy | SNP_POLICY_DBG);
+       else
+               test_sev(guest, type, policy | SEV_POLICY_NO_DBG);
        test_sev(guest, type, policy);
 
        if (type == KVM_X86_SEV_VM)
@@ -190,7 +205,10 @@ static void test_sev_smoke(void *guest, uint32_t type, 
uint64_t policy)
        if (kvm_has_cap(KVM_CAP_XCRS) &&
            (xgetbv(0) & kvm_cpu_supported_xcr0() & xf_mask) == xf_mask) {
                test_sync_vmsa(type, policy);
-               test_sync_vmsa(type, policy | SEV_POLICY_NO_DBG);
+               if (type == KVM_X86_SNP_VM)
+                       test_sync_vmsa(type, policy | SNP_POLICY_DBG);
+               else
+                       test_sync_vmsa(type, policy | SEV_POLICY_NO_DBG);
        }
 }
 
@@ -203,5 +221,8 @@ int main(int argc, char *argv[])
        if (kvm_cpu_has(X86_FEATURE_SEV_ES))
                test_sev_smoke(guest_sev_es_code, KVM_X86_SEV_ES_VM, 
SEV_POLICY_ES);
 
+       if (kvm_cpu_has(X86_FEATURE_SEV_SNP))
+               test_sev_smoke(guest_snp_code, KVM_X86_SNP_VM, 
snp_default_policy());
+
        return 0;
 }
-- 
2.43.0