Re: [PATCH 1/1 v2] KVM: MMU: Optimize guest page table walk

[Avi Kivity <avi@redhat.com>]

On 04/26/2011 05:40 PM, Takuya Yoshikawa wrote:
> On Tue, 26 Apr 2011 08:34:57 +0200
> Jan Kiszka<jan.kiszka@web.de>  wrote:
>
> >  >  Google said that there was a similar talk on LKML in 2004.
> >  >
> >  >  On that threads, Linus explained how to tackle on the 64-bit get_user
> >  >  implementation.  But I could not see what happened after that.
> >
> >  Mmh, maybe the kernel was lacking a real use case, so no one seriously
> >  cared.
> >
> >  I don't see a fundamental blocker for an x86-32 __get_user_8 version
> >  based on two mov. I would give it a try.
> >
> >  Jan
> >
>
> Thank you!
>
> Avi, do we revert the patch now, or ...?

Please post a simple patch that uses two get_user()s for that case 
(64-bit pte on 32-bit host).  Then work with the x86 tree to see if 
they'll accept 64-bit get_user(), and once they do, we can go back to a 
simple get_user() again.

btw, I think we can use __get_user() here since the address must have 
been already validated.

-- 
error compiling committee.c: too many arguments to function