linux-kernel - [PATCH] KVM: selftests: Avoid KVM_SET_CPUID2 after KVM_RUN in vmx_pmu_msrs

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Date:   Wed, 15 Dec 2021 17:16:17 +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,
        linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: selftests: Avoid KVM_SET_CPUID2 after KVM_RUN in vmx_pmu_msrs_test

Commit feb627e8d6f6 ("KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN")
forbade chaning vCPU's CPUID data after the first KVM_RUN but
vmx_pmu_msrs_test does exactly that. Test VM needs to be re-created after
vcpu_run().

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>
---
 tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c | 5 +++++
 1 file changed, 5 insertions(+)

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..17882f79deed 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
@@ -99,6 +99,11 @@ int main(int argc, char *argv[])
 	vcpu_run(vm, VCPU_ID);
 	ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);
 
+	/* Re-create guest VM after KVM_RUN so CPUID can be changed */
+	kvm_vm_free(vm);
+	vm = vm_create_default(VCPU_ID, 0, guest_code);
+	vcpu_set_cpuid(vm, VCPU_ID, cpuid);
+
 	/* testcase 2, check valid LBR formats are accepted */
 	vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, 0);
 	ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), 0);
-- 
2.33.1