From 2cc51560aed0edb291341089d3475e1fbe8bfd04 Mon Sep 17 00:00:00 2001 From: Eddie Dong Date: Mon, 21 May 2007 07:28:09 +0300 Subject: KVM: VMX: Avoid saving and restoring msr_efer on lightweight vmexit MSR_EFER.LME/LMA bits are automatically save/restored by VMX hardware, KVM only needs to save NX/SCE bits at time of heavy weight VM Exit. But clearing NX bits in host envirnment may cause system hang if the host page table is using EXB bits, thus we leave NX bits as it is. If Host NX=1 and guest NX=0, we can do guest page table EXB bits check before inserting a shadow pte (though no guest is expecting to see this kind of gp fault). If host NX=0, we present guest no Execute-Disable feature to guest, thus no host NX=0, guest NX=1 combination. This patch reduces raw vmexit time by ~27%. Me: fix compile warnings on i386. Signed-off-by: Yaozu (Eddie) Dong Signed-off-by: Avi Kivity --- drivers/kvm/kvm.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/kvm/kvm.h') diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h index c252efed49d..db2bc6f168c 100644 --- a/drivers/kvm/kvm.h +++ b/drivers/kvm/kvm.h @@ -255,6 +255,7 @@ struct kvm_stat { u32 request_irq_exits; u32 irq_exits; u32 light_exits; + u32 efer_reload; }; struct kvm_vcpu { @@ -289,6 +290,7 @@ struct kvm_vcpu { u64 ia32_misc_enable_msr; int nmsrs; int save_nmsrs; + int msr_offset_efer; #ifdef CONFIG_X86_64 int msr_offset_kernel_gs_base; #endif -- cgit v1.2.3-70-g09d2