From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
KVM unconditionally intercepts WRMSR to MSR_IA32_DEBUGCTLMSR. In the
unlikely event that L1 allows L2 to write L1's MSR_IA32_DEBUGCTLMSR, but
but saves L2's value on VM-Exit, update vmcs12 during L2's WRMSR so as
to eliminate the need to VMREAD the value from vmcs02 on nested VM-Exit.
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/vmx/nested.c | 4 +---
arch/x86/kvm/vmx/vmx.c | 8 ++++++++
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 68c031e2cc4d..138f27597c91 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3563,10 +3563,8 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
(vmcs12->vm_entry_controls & ~VM_ENTRY_IA32E_MODE) |
(vm_entry_controls_get(to_vmx(vcpu)) & VM_ENTRY_IA32E_MODE);
- if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_DEBUG_CONTROLS) {
+ if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_DEBUG_CONTROLS)
kvm_get_dr(vcpu, 7, (unsigned long *)&vmcs12->guest_dr7);
- vmcs12->guest_ia32_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
- }
if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_IA32_EFER)
vmcs12->guest_ia32_efer = vcpu->arch.efer;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ede2ac670f5b..975b2705c5b2 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1845,6 +1845,14 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
get_vmcs12(vcpu)->guest_sysenter_esp = data;
vmcs_writel(GUEST_SYSENTER_ESP, data);
break;
+ case MSR_IA32_DEBUGCTLMSR:
+ if (is_guest_mode(vcpu) && get_vmcs12(vcpu)->vm_exit_controls &
+ VM_EXIT_SAVE_DEBUG_CONTROLS)
+ get_vmcs12(vcpu)->guest_ia32_debugctl = data;
+
+ ret = kvm_set_msr_common(vcpu, msr_info);
+ break;
+
case MSR_IA32_BNDCFGS:
if (!kvm_mpx_supported() ||
(!msr_info->host_initiated &&
--
1.8.3.1
