Re: Re: Xen-unstable save error

[Keir Fraser <keir.fraser@eu.citrix.com>]

On 22/06/2010 07:48, "Jan Beulich" <JBeulich@novell.com> wrote:

>>>> On 22.06.10 at 08:23, Michal Novotny <minovotn@redhat.com> wrote:
>> Jan, as we were solving this with Keir on the list I was unable to save
>> the HVM guest properly and reverting your c/s 21615 helped and with your
>> patch reverted it was working fine. Any idea why there were so type
>> failures for all the pages of HVM guest?
> 
> Not really, and I think you will need to find out by instrumenting the
> hypercall implementation (XEN_DOMCTL_getpageframeinfo{2,3}) -
> really, type failures should only happen for grant frames and I/O
> memory pages (as you can see in the code, for the function to
> report XTAB either the MFN must be invalid, must be a Xen frame,
> or it must be impossible to obtain a reference to the page - all of
> which shouldn't hold for the majority of a HVM guest's pages).

Michal, is it possible you are running new tools against a slightly older
hypervisor? The tools changes had a corresponding, non-version-checked,
modification to a hypercall. Without running the modified hypervisor, HVM
save would indeed behave very oddly!

 -- Keir