KVM: x86: SVM: add module param to control LBR virtualization
This is useful for debug and also makes it consistent with
the rest of the SVM optional features.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index c770dce..270a091 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -186,6 +186,10 @@ module_param(vls, int, 0444);
static int vgif = true;
module_param(vgif, int, 0444);
+/* enable/disable LBR virtualization */
+static int lbrv = true;
+module_param(lbrv, int, 0444);
+
/*
* enable / disable AVIC. Because the defaults differ for APICv
* support between VMX and SVM we cannot use module_param_named.
@@ -1059,6 +1063,13 @@ static __init int svm_hardware_setup(void)
pr_info("Virtual GIF supported\n");
}
+ if (lbrv) {
+ if (!boot_cpu_has(X86_FEATURE_LBRV))
+ lbrv = false;
+ else
+ pr_info("LBR virtualization supported\n");
+ }
+
svm_set_cpu_caps();
/*
@@ -2923,7 +2934,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
svm->tsc_aux = data;
break;
case MSR_IA32_DEBUGCTLMSR:
- if (!boot_cpu_has(X86_FEATURE_LBRV)) {
+ if (!lbrv) {
vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTL 0x%llx, nop\n",
__func__, data);
break;