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authorSean Christopherson <[email protected]>2024-08-02 11:55:04 -0700
committerSean Christopherson <[email protected]>2024-11-01 09:22:30 -0700
commitbc2ca3680b30869ee9a764ab72c143070f1afec8 (patch)
treebeb916757b4aad1851ee4f81b966a625016db1ed
parent2142ac663a6a72ac868d0768681b1355e3a703eb (diff)
KVM: x86: Disallow changing MSR_PLATFORM_INFO after vCPU has run
Tag MSR_PLATFORM_INFO as a feature MSR (because it is), i.e. disallow it from being modified after the vCPU has run. To make KVM's selftest compliant, simply delete the userspace MSR write that restores KVM's original value at the end of the test. Verifying that userspace can write back what it originally read is uninteresting in this particular case, because KVM doesn't enforce _any_ bits in the MSR, i.e. userspace should be able to write any arbitrary value. Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]>
-rw-r--r--arch/x86/kvm/x86.c1
-rw-r--r--tools/testing/selftests/kvm/x86_64/platform_info_test.c2
2 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3787e6a71743..16804637ba97 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -451,6 +451,7 @@ static const u32 msr_based_features_all_except_vmx[] = {
MSR_IA32_UCODE_REV,
MSR_IA32_ARCH_CAPABILITIES,
MSR_IA32_PERF_CAPABILITIES,
+ MSR_PLATFORM_INFO,
};
static u32 msr_based_features[ARRAY_SIZE(msr_based_features_all_except_vmx) +
diff --git a/tools/testing/selftests/kvm/x86_64/platform_info_test.c b/tools/testing/selftests/kvm/x86_64/platform_info_test.c
index eda88080c186..9cbf283ebc55 100644
--- a/tools/testing/selftests/kvm/x86_64/platform_info_test.c
+++ b/tools/testing/selftests/kvm/x86_64/platform_info_test.c
@@ -72,8 +72,6 @@ int main(int argc, char *argv[])
}
done:
- vcpu_set_msr(vcpu, MSR_PLATFORM_INFO, msr_platform_info);
-
kvm_vm_free(vm);
return 0;