linux-kernel - Re: [PATCH v2] KVM: selftests: x86: Fix test failure on arch lbr capable platforms

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Date:   Thu, 12 May 2022 15:23:08 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Yang Weijiang <weijiang.yang@...el.com>, likexu@...cent.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v2] KVM: selftests: x86: Fix test failure on arch lbr
 capable platforms

On 5/12/22 10:40, Yang Weijiang wrote:
> On Arch LBR capable platforms, LBR_FMT in perf capability msr is 0x3f,
> so the last format test will fail. Use a true invalid format(0x30) for
> the test if it's running on these platforms. Opportunistically change
> the file name to reflect the tests actually carried out.
> 
> v2:
> Select a true invalid format instead of skipping the test on arch lbr
> capable platforms.
> 
> Suggested-by: Paolo Bonzini <pbonzini@...hat.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
> ---
>   tools/testing/selftests/kvm/Makefile           |  2 +-
>   ...vmx_pmu_msrs_test.c => vmx_pmu_caps_test.c} | 18 ++++++++++--------
>   2 files changed, 11 insertions(+), 9 deletions(-)
>   rename tools/testing/selftests/kvm/x86_64/{vmx_pmu_msrs_test.c => vmx_pmu_caps_test.c} (83%)
> 
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index 681b173aa87c..9a1a84803b01 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -81,7 +81,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/xapic_state_test
>   TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
>   TEST_GEN_PROGS_x86_64 += x86_64/debug_regs
>   TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test
> -TEST_GEN_PROGS_x86_64 += x86_64/vmx_pmu_msrs_test
> +TEST_GEN_PROGS_x86_64 += x86_64/vmx_pmu_caps_test
>   TEST_GEN_PROGS_x86_64 += x86_64/xen_shinfo_test
>   TEST_GEN_PROGS_x86_64 += x86_64/xen_vmcall_test
>   TEST_GEN_PROGS_x86_64 += x86_64/sev_migrate_tests
> diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
> similarity index 83%
> rename from tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
> rename to tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
> index 2454a1f2ca0c..97b7fd4a9a3d 100644
> --- a/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
> @@ -1,15 +1,14 @@
>   // SPDX-License-Identifier: GPL-2.0
>   /*
> - * VMX-pmu related msrs test
> + * Test for VMX-pmu perf capability msr
>    *
>    * Copyright (C) 2021 Intel Corporation
>    *
> - * Test to check the effect of various CPUID settings
> - * on the MSR_IA32_PERF_CAPABILITIES MSR, and check that
> - * whatever we write with KVM_SET_MSR is _not_ modified
> - * in the guest and test it can be retrieved with KVM_GET_MSR.
> - *
> - * Test to check that invalid LBR formats are rejected.
> + * Test to check the effect of various CPUID settings on
> + * MSR_IA32_PERF_CAPABILITIES MSR, and check that what
> + * we write with KVM_SET_MSR is _not_ modified by the guest
> + * and check it can be retrieved with KVM_GET_MSR, also test
> + * the invalid LBR formats are rejected.
>    */
>   
>   #define _GNU_SOURCE /* for program_invocation_short_name */
> @@ -107,8 +106,11 @@ int main(int argc, char *argv[])
>   	ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), (u64)host_cap.lbr_format);
>   
>   	/* testcase 3, check invalid LBR format is rejected */
> -	ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
> +	/* Note, on Arch LBR capable platforms, LBR_FMT in perf capability msr is 0x3f,
> +	 * to avoid the failure, use a true invalid format 0x30 for the test. */
> +	ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, 0x30);
>   	TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
>   
> +	printf("Completed perf capability tests.\n");
>   	kvm_vm_free(vm);
>   }
> 
> base-commit: 672c0c5173427e6b3e2a9bbb7be51ceeec78093a

Applied, thanks.

Paolo