Avi Kivity wrote:
> Dong, Eddie wrote:
>> This patch provides short cut handling for light weight VM Exit,
>> which can boost KB performance 11% under FC5 guest.
>> Any comments?
> 
> While the patch looks good, it kills FC6 x86_64 boot with a double
> fault. Guest kernel is 2.6.18-1.2798. dmesg says
> 
> inject_page_fault: double fault 0x7fff79b58fd8 @ 0xffffffff8025cca1
> 
I think I know the reason, the SYSCALL_MASK & LSTAR update in guest
needs to 
update the physical side MSR after this patch.  With this update in
vmx_set_msr, 
I get it up on a RHEL5U 64 bits guest but no time to check the detail
performance 
gain yet. (will report after May day national holiday 5/1--5/8 in PRC)

BTW, I have another patch in hand to further reduce MSR save/restore and
thus 
improve performance more for lightweight VM Exit. Base on my observation
for FC5 32 bits
guest, 93% VM Exit will fall into the lightweight path.

Thx, eddie

Attachment: lightweight4.patch
Description: lightweight4.patch

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