linux-kernel - [PATCH v2 1/2] KVM: selftests: vmx_pmu_msrs_test: Drop tests mangling guest visible CPUIDs

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Date:   Thu, 16 Dec 2021 17:52:12 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>, oliver.sang@...el.com,
        Like Xu <like.xu@...ux.intel.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] KVM: selftests: vmx_pmu_msrs_test: Drop tests mangling guest visible CPUIDs

Host initiated writes to MSR_IA32_PERF_CAPABILITIES should not depend
on guest visible CPUIDs and (incorrect) KVM logic implementing it is
about to change. Also, KVM_SET_CPUID{,2} after KVM_RUN is now forbidden
and causes test to fail.

Reported-by: kernel test robot <oliver.sang@...el.com>
Fixes: feb627e8d6f6 ("KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN")
Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 .../selftests/kvm/x86_64/vmx_pmu_msrs_test.c    | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
index 23051d84b907..2454a1f2ca0c 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
@@ -110,22 +110,5 @@ int main(int argc, char *argv[])
 	ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
 	TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
 
-	/* testcase 4, set capabilities when we don't have PDCM bit */
-	entry_1_0->ecx &= ~X86_FEATURE_PDCM;
-	vcpu_set_cpuid(vm, VCPU_ID, cpuid);
-	ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
-	TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
-
-	/* testcase 5, set capabilities when we don't have PMU version bits */
-	entry_1_0->ecx |= X86_FEATURE_PDCM;
-	eax.split.version_id = 0;
-	entry_1_0->ecx = eax.full;
-	vcpu_set_cpuid(vm, VCPU_ID, cpuid);
-	ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_FW_WRITES);
-	TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
-
-	vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, 0);
-	ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), 0);
-
 	kvm_vm_free(vm);
 }
-- 
2.33.1