Re: [PATCH] KVM: MMU: Do not unconditionally read PDPTE from guest memory

[Avi Kivity <avi@redhat.com>]

On 08/02/2011 12:31 PM, Roedel, Joerg wrote:
> On Sun, Jul 31, 2011 at 04:08:44AM -0400, Avi Kivity wrote:
> >  On 07/29/2011 02:31 PM, Roedel, Joerg wrote:
> >  >  On Thu, Jul 28, 2011 at 04:36:17AM -0400, Avi Kivity wrote:
> >  >  >   Architecturally, PDPTEs are cached in the PDPTRs when CR3 is reloaded.
> >  >  >   On SVM, it is not possible to implement this, but on VMX this is possible
> >  >  >   and was indeed implemented until nested SVM changed this to unconditionally
> >  >  >   read PDPTEs dynamically.  This has noticable impact when running PAE guests.
> >  >  >
> >  >  >   Fix by changing the MMU to read PDPTRs from the cache, falling back to
> >  >  >   reading from memory for the nested MMU.
> >  >  >
> >  >  >   Signed-off-by: Avi Kivity<avi@redhat.com>
> >  >
> >  >  Hmm, interesting. Sorry for breaking it. I tested the patch on nested
> >  >  svm, it works fine.
> >
> >  Does pae-on-pae work for you?
>
> Only tested pae-on-longmode. I'll see if I can find my 32bit
> installation again and test this too.

I wanted to test it since any mixup in where the PTPTRs were taken from 
would be readily apparent.  But it crashes even without the patch.

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