KVM: VMX: Use vmx to inject real-mode interrupts

Instead of injecting real-mode interrupts by writing the interrupt frame into
guest memory, abuse vmx by injecting a software interrupt.  We need to
pretend the software interrupt instruction had a length > 0, so we have to
adjust rip backward.

This lets us not to mess with writing guest memory, which is complex and also
sleeps.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/kvm/vmx.h b/drivers/kvm/vmx.h
index c84bd373315..d757b36c2fb 100644
--- a/drivers/kvm/vmx.h
+++ b/drivers/kvm/vmx.h
@@ -233,6 +233,7 @@ enum vmcs_field {
 
 #define INTR_TYPE_EXT_INTR              (0 << 8) /* external interrupt */
 #define INTR_TYPE_EXCEPTION             (3 << 8) /* processor exception */
+#define INTR_TYPE_SOFT_INTR             (4 << 8) /* software interrupt */
 
 /*
  * Exit Qualifications for MOV for Control Register Access