diff mbox series

[7/9] KVM: x86: Remove ordering check b/w MSR_PLATFORM_INFO and MISC_FEATURES_ENABLES

Message ID 20240802185511.305849-8-seanjc@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86: Add a quirk for feature MSR initialization | expand

Commit Message

Sean Christopherson Aug. 2, 2024, 6:55 p.m. UTC 
Drop KVM's odd restriction that disallows clearing CPUID_FAULT in
MSR_PLATFORM_INFO if CPL>0 CPUID faulting is enabled in
MSR_MISC_FEATURES_ENABLES.  KVM generally doesn't require specific
ordering when userspace sets MSRs, and the completely arbitrary order of
MSRs in emulated_msrs_all means that a userspace that uses KVM's list
verbatim could run afoul of the check.

Dropping the restriction obviously means that userspace could stuff a
nonsensical vCPU model, but that's the case all over KVM.  KVM typically
restricts userspace MSR writes only when it makes things easier for KVM
and/or userspace.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/x86.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8bce40c649b4..32483cc16d6a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4119,9 +4119,7 @@  int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		vcpu->arch.osvw.status = data;
 		break;
 	case MSR_PLATFORM_INFO:
-		if (!msr_info->host_initiated ||
-		    (!(data & MSR_PLATFORM_INFO_CPUID_FAULT) &&
-		     cpuid_fault_enabled(vcpu)))
+		if (!msr_info->host_initiated)
 			return 1;
 		vcpu->arch.msr_platform_info = data;
 		break;