Re: [Xen-devel] Re: issues with movnti emulation

[Tim Deegan <Tim.Deegan@xxxxxxxxxx>]

At 17:13 +0000 on 20 Nov (1227201181), Keir Fraser wrote:
> I think the issue is that I did a bad backport to 3.3. The 'case 0xc3'
> should be under twobyte_special_insn rather than twobyte_insn, right? The
> two separate paths got merged into one in xen-unstable.
> 
> Of course this data corruption ought only to happen in cases where we'd
> previously have failed an mmio emulation (and hence probably killed the
> guest kernel?).

A more likely culprit is that some OSes use movnti to zero pages that
used to be pagetables; when we couldn't emulate it we just (correctly)
unshadowed those pages.

Cheers,

Tim.

> 
>  -- Keir
> 
> On 20/11/08 16:38, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:
> 
> > We've got reports of that change causing HVM data corruption issues. While
> > I can't see what's wrong with the patch, I'd suggest at least reverting it
> > from
> > the 3.3 tree (which is what our code is based upon) for the time being.
> > 
> > Jan
> > 
> 
> 
> 
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-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]

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