KVM: VMX: Handle NMIs before enabling interrupts and preemption

This makes sure we handle NMI on the current cpu, and that we don't service
maskable interrupts before non-maskable ones.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 4f115a8e45ef..bcc1e398a976 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1760,10 +1760,8 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 set_bit(irq / BITS_PER_LONG, &vcpu->irq_summary);
         }
 
-        if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200) { /* nmi */
-                asm ("int $2");
-                return 1;
-        }
+        if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200) /* nmi */
+                return 1;  /* already handled by vmx_vcpu_run() */
 
         if (is_no_device(intr_info)) {
                 vmx_fpu_activate(vcpu);
@@ -2196,6 +2194,7 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
 static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
+        u32 intr_info;
 
         /*
          * Loading guest fpu may have cleared host cr0.ts
@@ -2322,6 +2321,12 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
         asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
         vmx->launched = 1;
+
+        intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
+
+        /* We need to handle NMIs before interrupts are enabled */
+        if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200) /* nmi */
+                asm("int $2");
 }
 
 static void vmx_inject_page_fault(struct kvm_vcpu *vcpu,