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-rw-r--r--arch/x86/kvm/vmx.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f5e8dce8046c..f7b61687bd79 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3622,8 +3622,16 @@ static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
- unsigned long hw_cr4 = cr4 | (to_vmx(vcpu)->rmode.vm86_active ?
- KVM_RMODE_VM_CR4_ALWAYS_ON : KVM_PMODE_VM_CR4_ALWAYS_ON);
+ /*
+ * Pass through host's Machine Check Enable value to hw_cr4, which
+ * is in force while we are in guest mode. Do not let guests control
+ * this bit, even if host CR4.MCE == 0.
+ */
+ unsigned long hw_cr4 =
+ (cr4_read_shadow() & X86_CR4_MCE) |
+ (cr4 & ~X86_CR4_MCE) |
+ (to_vmx(vcpu)->rmode.vm86_active ?
+ KVM_RMODE_VM_CR4_ALWAYS_ON : KVM_PMODE_VM_CR4_ALWAYS_ON);
if (cr4 & X86_CR4_VMXE) {
/*