Re: [Xen-devel] [PATCH] VMX: disable SMEP feature when guest is in non-paging mode

["Xu, Dongxiao" <dongxiao.xu@xxxxxxxxx>]

> -----Original Message-----
> From: Keir Fraser [mailto:keir.xen@xxxxxxxxx]
> Sent: Thursday, January 31, 2013 9:12 AM
> To: Xu, Dongxiao; Tim Deegan
> Cc: xen-devel@xxxxxxxxxxxxx
> Subject: Re: [Xen-devel] [PATCH] VMX: disable SMEP feature when guest is in
> non-paging mode
> 
> On 30/01/2013 16:56, "Xu, Dongxiao" <dongxiao.xu@xxxxxxxxx> wrote:
> 
> >>> Shouldn't this be handled on CR0 writes as well as CR4?  The SMEP bit of
> >>> hw_cr[4] ought to be cleared and set whenever CR0_PG is changed.
> >>
> >> That's what I would expect too.
> >
> > In the case 0 (CR0 update) in vmx_update_guest_cr(), it will call
> > vmx_update_guest_cr(v, 4) to adjust CR4 related bits if certain bits (PG, 
> > PE)
> > in CR0 changed.
> 
> Good point!
> 
> In fact we can make that cr4 update unconditional and simplify the cr0
> handling a bit more.

Yes, I saw your changes, which makes the code more neat.

Thanks,
Dongxiao

> 
>  -- Keir
> 


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel