KVM: Lazy FPU support for SVM

Avoid saving and restoring the guest fpu state on every exit.  This
shaves ~100 cycles off the guest/host switch.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index d1a90c5d76ce..61ff085df7e6 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -63,6 +63,7 @@
 #define FX_BUF_SIZE (2 * FX_IMAGE_SIZE + FX_IMAGE_ALIGN)
 
 #define DE_VECTOR 0
+#define NM_VECTOR 7
 #define DF_VECTOR 8
 #define TS_VECTOR 10
 #define NP_VECTOR 11
@@ -301,6 +302,7 @@ struct kvm_vcpu {
         char fx_buf[FX_BUF_SIZE];
         char *host_fx_image;
         char *guest_fx_image;
+        int fpu_active;
 
         int mmio_needed;
         int mmio_read_completed;