KVM: Avoid saving and restoring some host CPU state on lightweight vmexit

Many msrs and the like will only be used by the host if we schedule() or
return to userspace.  Therefore, we avoid saving them if we handle the
exit within the kernel, and if a reschedule is not requested.

Based on a patch from Eddie Dong <eddie.dong@intel.com> with a couple of
fixes by me.

Signed-off-by: Yaozu(Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 8f1f07adb04e..7d682586423b 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -72,6 +72,7 @@ static struct kvm_stats_debugfs_item {
         { "halt_exits", STAT_OFFSET(halt_exits) },
         { "request_irq", STAT_OFFSET(request_irq_exits) },
         { "irq_exits", STAT_OFFSET(irq_exits) },
+        { "light_exits", STAT_OFFSET(light_exits) },
         { NULL }
 };