[Xen-devel] Re: One potential issue of shadow fault emulation

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 21/12/07 17:21, "Tim Deegan" <Tim.Deegan@xxxxxxxxxx> wrote:

> I think it's cleanest to just fail the emulation if we find we're
> writing to the vlapic, rather than adding special-case code to detect
> and handle TPR writes within the page.  Unless this is a particularly
> common path and would have a measurable performance impact for the extra
> VMEXIT.

Probably gfn_to_mfn() should explicitly check for vmx_apic_access_mfn and
return INVALID_MFN instead. That will fix all emulation routines by causing
them to take their mmio path (or bail if they don't have them) which is the
correct behaviour for this case.

This is certainly important enough to fix for 3.2.0 (and 3.1.3).

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel