linux-kernel - Re: [PATCH] KVM: selftests: Use GUEST_ASSERT_EQ() to check exit codes in Hyper-V SVM test

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Message-ID: <ukijxjc4bprwhls6c2v3i7l7ghxqhabe42lje2fgke7rnuxocs@5nakwleh3wiw>
Date: Fri, 14 Nov 2025 16:58:49 +0000
From: Yosry Ahmed <yosry.ahmed@...ux.dev>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: selftests: Use GUEST_ASSERT_EQ() to check exit
 codes in Hyper-V SVM test

On Fri, Nov 14, 2025 at 08:40:01AM -0800, Sean Christopherson wrote:
> Use GUEST_ASSERT_EQ() instead of GUEST_ASSERT(x == SVM_EXIT_<code>) in the
> Hyper-V SVM test so that the test prints the actual vs. expected values on
> failure.  E.g. instead of printing:
> 
>   vmcb->control.exit_code == SVM_EXIT_VMMCALL
> 
> print:
> 
>  0x7c != 0x81 (vmcb->control.exit_code != SVM_EXIT_VMMCALL)
> 
> Cc: Yosry Ahmed <yosry.ahmed@...ux.dev>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

LGTM:
Reviewed-by: Yosry Ahmed <yosry.ahmed@...ux.dev>

For the record, there are a few more instances:

$ git grep "GUEST_ASSERT(vmcb->control.exit_code"
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == HV_SVM_EXITCODE_ENL);
tools/testing/selftests/kvm/x86/hyperv_svm_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
tools/testing/selftests/kvm/x86/state_test.c:   GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
tools/testing/selftests/kvm/x86/state_test.c:   GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
tools/testing/selftests/kvm/x86/svm_int_ctl_test.c:     GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
tools/testing/selftests/kvm/x86/svm_nested_soft_inject_test.c:  __GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL,
tools/testing/selftests/kvm/x86/svm_nested_soft_inject_test.c:  __GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_HLT,
tools/testing/selftests/kvm/x86/svm_vmcall_test.c:      GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);

There's also a lot for VMX, you can find all/most of them by running git
grep "vmreadz(VM_EXIT_REASON)".

> ---
>  .../testing/selftests/kvm/x86/hyperv_svm_test.c  | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/x86/hyperv_svm_test.c b/tools/testing/selftests/kvm/x86/hyperv_svm_test.c
> index 0ddb63229bcb..7fb988df5f55 100644
> --- a/tools/testing/selftests/kvm/x86/hyperv_svm_test.c
> +++ b/tools/testing/selftests/kvm/x86/hyperv_svm_test.c
> @@ -94,7 +94,7 @@ static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
>  
>  	GUEST_SYNC(2);
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_VMMCALL);
>  	GUEST_SYNC(4);
>  	vmcb->save.rip += 3;
>  
> @@ -102,13 +102,13 @@ static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
>  	vmcb->control.intercept |= 1ULL << INTERCEPT_MSR_PROT;
>  	__set_bit(2 * (MSR_FS_BASE & 0x1fff), svm->msr + 0x800);
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_MSR);
>  	vmcb->save.rip += 2; /* rdmsr */
>  
>  	/* Enable enlightened MSR bitmap */
>  	hve->hv_enlightenments_control.msr_bitmap = 1;
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_MSR);
>  	vmcb->save.rip += 2; /* rdmsr */
>  
>  	/* Intercept RDMSR 0xc0000101 without telling KVM about it */
> @@ -117,13 +117,13 @@ static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
>  	vmcb->control.clean |= HV_VMCB_NESTED_ENLIGHTENMENTS;
>  	run_guest(vmcb, svm->vmcb_gpa);
>  	/* Make sure we don't see SVM_EXIT_MSR here so eMSR bitmap works */
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_VMMCALL);
>  	vmcb->save.rip += 3; /* vmcall */
>  
>  	/* Now tell KVM we've changed MSR-Bitmap */
>  	vmcb->control.clean &= ~HV_VMCB_NESTED_ENLIGHTENMENTS;
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_MSR);
>  	vmcb->save.rip += 2; /* rdmsr */
>  
>  
> @@ -132,16 +132,16 @@ static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
>  	 * no VMCALL exit expected.
>  	 */
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_MSR);
>  	vmcb->save.rip += 2; /* rdmsr */
>  	/* Enable synthetic vmexit */
>  	*(u32 *)(hv_pages->partition_assist) = 1;
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == HV_SVM_EXITCODE_ENL);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  HV_SVM_EXITCODE_ENL);
>  	GUEST_ASSERT(vmcb->control.exit_info_1 == HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH);
>  
>  	run_guest(vmcb, svm->vmcb_gpa);
> -	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
> +	GUEST_ASSERT_EQ(vmcb->control.exit_code,  SVM_EXIT_VMMCALL);
>  	GUEST_SYNC(6);
>  
>  	GUEST_DONE();
> 
> base-commit: 16ec4fb4ac95d878b879192d280db2baeec43272
> -- 
> 2.52.0.rc1.455.g30608eb744-goog
>