Re: [Xen-devel] Xen4.2 S3 regression?

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 04.09.12 at 14:27, Ben Guthro <ben@xxxxxxxxxx> wrote:
> I've put the console log of this test run here:
> https://citrix.sharefile.com/d/sdc383e252fb41c5a 
> 
> (again, so as not to clog everyone's inbox)
> 
> I have not yet gone through the log in its entirety yet, but thought I
> would first send it to you to see if you had something in particular
> you were looking for.
> 
> The file name is console-S3-MSI.txt

I think that nailed it: pci_restore_msi_state() passed a pointer
to the stored entry->msg to write_msi_msg(), but with interrupt
remapping enabled that function's call to
iommu_update_ire_from_msi() alters the passed in struct
msi_msg instance. As the stored value is used for nothing but
a subsequent (second) restore, a problem would only arise if
between the two saves to further writing of the stored entry
would occur (i.e. no intermediate call to set_msi_affinity()).

Attached the advertised next version of the debugging patch
(printks - slightly altered - left in to catch eventual further
problems or to deal with my analysis being wrong; none of the
"bogus!" ones should now trigger anymore). If this works, I'd
be curious to see how much of your other workaround code
you could then remove without breaking things again.

Jan

Attachment: S3-MSI.patch
Description: Text document

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