Commit bff903e8 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: SVM: Passthrough MSR_IA32_PRED_CMD based purely on host+guest CPUID 



Passthrough MSR_IA32_PRED_CMD based purely on whether or not the MSR is
supported and enabled, i.e. don't wait until the first write.  There's no
benefit to deferred passthrough, and the extra logic only adds complexity.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-4-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9a4c4850

arch/x86/kvm/svm/svm.c

+4 −1
Original line number Diff line number Diff line
@@ -2955,7 +2955,6 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) 
			break;



		wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB);

		set_msr_interception(vcpu, svm->msrpm, MSR_IA32_PRED_CMD, 0, 1);

		break;

	case MSR_AMD64_VIRT_SPEC_CTRL:

		if (!msr->host_initiated &&
@@ -4151,6 +4150,10 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) 


	svm_recalc_instruction_intercepts(vcpu, svm);



	if (boot_cpu_has(X86_FEATURE_IBPB))

		set_msr_interception(vcpu, svm->msrpm, MSR_IA32_PRED_CMD, 0,

				     !!guest_has_pred_cmd_msr(vcpu));



	/* For sev guests, the memory encryption bit is not reserved in CR3.  */

	if (sev_guest(vcpu->kvm)) {

		best = kvm_find_cpuid_entry(vcpu, 0x8000001F);