Re: [Xen-ia64-devel] Patch: XEN_HYPER_ITC_D and XEN_HYPER_ITC_I in vhpt_miss

[Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxxxxxxx>]

Am Mittwoch, 24. Mai 2006 06:07 schrieb Tian, Kevin:
> >From: Magenheimer, Dan (HP Labs Fort Collins)
> >Sent: 2006年5月23日 22:40
> >> > > > May it be that XEN_HYPER_ITC_D and XEN_HYPER_ITC_I are
> >in
> >> > >
> >> > > the reverse
> >> > >
> >> > > > order?
> >> > >
> >> > > Good catch.
> >> > >
> >> > > Feel free to send a patch.
> >> >
> >> > Does this code ever get executed?  The VHPT is pinned by
> >> > a TR, correct?
> >
> >Oops, Xen's VHPT is pinned, the guest's isn't pinned.
> >
> >> For sure it is strange we never hit this bug ;-)
> >
> >Yes, it looks like the faulty code should get executed.
> >Maybe it quickly
> >fixes itself because the wrong vtlb gets inserted,
> >then another miss immediately occurs which is not
> >a VHPT fault so the correct vtlb gets inserted.
> 
> Definitely. The key point is that vhpt entry is inserted after above bogus 
> place and then TLB miss immediately happens after resuming with 
> hardware triggered to walk vhpt table by inserting desired mapping. 
> Above two insertions are only optimization code which don't hurt 
> anything even not being there.
> 
> >
> >Anyway, yes, please submit a patch!
> >
> >Dan
> >
> 
> Yes, patch is needed.
> 
> Thanks,
> Kevin
> 

Hi,

I hope the patch is in the right format.
Thanks.

Dietmar.

Attachment: swap_ITC_I-ITC_D.patch
Description: Text Data

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