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>
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index d1a90c5..61ff085 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 @@
 	char fx_buf[FX_BUF_SIZE];
 	char *host_fx_image;
 	char *guest_fx_image;
+	int fpu_active;
 
 	int mmio_needed;
 	int mmio_read_completed;