+
+ /*
+ * Move the LBR msrs back to the vmcb01 to avoid copying them
+ * on nested guest entries.
+ */
+ if (is_guest_mode(vcpu))
+ svm_copy_lbrs(svm->vmcb01.ptr, svm->vmcb);
+}
+
+static int svm_get_lbr_msr(struct vcpu_svm *svm, u32 index)
+{
+ /*
+ * If the LBR virtualization is disabled, the LBR msrs are always
+ * kept in the vmcb01 to avoid copying them on nested guest entries.
+ *
+ * If nested, and the LBR virtualization is enabled/disabled, the msrs
+ * are moved between the vmcb01 and vmcb02 as needed.
+ */
+ struct vmcb *vmcb =
+ (svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) ?
+ svm->vmcb : svm->vmcb01.ptr;
+
+ switch (index) {
+ case MSR_IA32_DEBUGCTLMSR:
+ return vmcb->save.dbgctl;
+ case MSR_IA32_LASTBRANCHFROMIP:
+ return vmcb->save.br_from;
+ case MSR_IA32_LASTBRANCHTOIP:
+ return vmcb->save.br_to;
+ case MSR_IA32_LASTINTFROMIP:
+ return vmcb->save.last_excp_from;
+ case MSR_IA32_LASTINTTOIP:
+ return vmcb->save.last_excp_to;
+ default:
+ KVM_BUG(false, svm->vcpu.kvm,
+ "%s: Unknown MSR 0x%x", __func__, index);
+ return 0;
+ }
+}
+
+void svm_update_lbrv(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ bool enable_lbrv = svm_get_lbr_msr(svm, MSR_IA32_DEBUGCTLMSR) &
+ DEBUGCTLMSR_LBR;
+
+ bool current_enable_lbrv = !!(svm->vmcb->control.virt_ext &
+ LBR_CTL_ENABLE_MASK);
+
+ if (enable_lbrv == current_enable_lbrv)
+ return;
+
+ if (enable_lbrv)
+ svm_enable_lbrv(vcpu);
+ else
+ svm_disable_lbrv(vcpu);