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

[Tim Deegan <Tim.Deegan@xxxxxxxxxx>]

At 21:54 +0000 on 21 Dec (1198274059), Keir Fraser wrote:
> 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.

That will disable the VMX TPR optimization too -- the p2m lookup needs
to return this magic page when the shadow propagation code looks it up
but not when other callers look it up.  Maybe the existing scheme for
mapping MMIO pages directly would do; mark the page as direct MMIO
instead of as RAM?  Otherwise at least one of the shadow propagation
code and the emulator needs to special-case the vlapic page.

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Citrix Systems.
[Company #5334508: XenSource UK Ltd, reg'd c/o EC2Y 5EB, UK.]

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