KVM: VMX: Check cpl before emulating debug register access
Debug registers may only be accessed from cpl 0. Unfortunately, vmx will
code to emulate the instruction even though it was issued from guest
userspace, possibly leading to an unexpected trap later.
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index cc6e00a..f381201 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2934,6 +2934,8 @@
unsigned long val;
int dr, reg;
+ if (!kvm_require_cpl(vcpu, 0))
+ return 1;
dr = vmcs_readl(GUEST_DR7);
if (dr & DR7_GD) {
/*