linux-kernel - Re: [PATCH v5 3/9] KVM: selftests: SEV-SNP test for KVM_SEV

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Message-ID: <85ikpzm8zu.fsf@amd.com>
Date: Tue, 28 Jan 2025 12:13:41 +0000
From: Nikunj A Dadhania <nikunj@....com>
To: "Pratik R. Sampat" <prsampat@....com>, <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>, <michael.roth@....com>, <sraithal@....com>,
	<prsampat@....com>
Subject: Re: [PATCH v5 3/9] KVM: selftests: SEV-SNP test for KVM_SEV_INIT2

"Pratik R. Sampat" <prsampat@....com> writes:

> Add the X86_FEATURE_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.
>
> Signed-off-by: Pratik R. Sampat <prsampat@....com>

With a minor nit below:

Reviewed-by: Nikunj A Dadhania <nikunj@....com>

> ---
>  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..1e05e610bb06 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_SNP			KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 4)

Can we keep the naming same as in cpufeatures.h: X86_FEATURE_SEV_SNP ?

Regards
Nikunj

>
>  /*
>   * 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..3f8fb2cc3431 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_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