KVM: VMX: Avoid saving and restoring msrs on lightweight vmexit

In a lightweight exit (where we exit and reenter the guest without
scheduling or exiting to userspace in between), we don't need various
msrs on the host, and avoiding shuffling them around reduces raw exit
time by 8%.

i386 compile fix by Daniel Hecken <dh@bahntechnik.de>.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index fc4a6c1235f0..c252efed49d9 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -288,6 +288,10 @@ struct kvm_vcpu {
         u64 apic_base;
         u64 ia32_misc_enable_msr;
         int nmsrs;
+        int save_nmsrs;
+#ifdef CONFIG_X86_64
+        int msr_offset_kernel_gs_base;
+#endif
         struct vmx_msr_entry *guest_msrs;
         struct vmx_msr_entry *host_msrs;