linux-kernel - [PATCH v6 3/9] KVM: selftests: SEV-SNP test for KVM_SEV

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Message-ID: <20250203223205.36121-4-prsampat@amd.com>
Date: Mon, 3 Feb 2025 16:31:59 -0600
From: "Pratik R. Sampat" <prsampat@....com>
To: <linux-kernel@...r.kernel.org>, <x86@...nel.org>, <kvm@...r.kernel.org>,
	<linux-crypto@...r.kernel.org>, <linux-kselftest@...r.kernel.org>
CC: <seanjc@...gle.com>, <pbonzini@...hat.com>, <thomas.lendacky@....com>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>, <shuah@...nel.org>, <pgonda@...gle.com>,
	<ashish.kalra@....com>, <nikunj@....com>, <pankaj.gupta@....com>,
	<michael.roth@....com>, <sraithal@....com>, <prsampat@....com>
Subject: [PATCH v6 3/9] KVM: selftests: SEV-SNP test for KVM_SEV_INIT2

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@....com>
Tested-by: Srikanth Aithal <sraithal@....com>
Signed-off-by: Pratik R. Sampat <prsampat@....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