Re: [Qemu-devel] QEMU postcopy-test failing on ppc64

[Dr. David Alan Gilbert]

* Thomas Huth (address@hidden) wrote:
> On 15.11.2016 16:18, Stefan Hajnoczi wrote:
> > On Tue, Nov 15, 2016 at 2:56 PM, Greg Kurz <address@hidden> wrote:
> >> On Tue, 15 Nov 2016 11:14:57 +0000
> >> Stefan Hajnoczi <address@hidden> wrote:
> >>
> >>> On Tue, Nov 15, 2016 at 10:09 AM, Greg Kurz <address@hidden> wrote:
> >>>> On Tue, 15 Nov 2016 10:53:35 +0100
> >>>> Laurent Vivier <address@hidden> wrote:
> >>>>
> >>>>> On 14/11/2016 21:52, Stefan Hajnoczi wrote:
> >>>>>> I hit a failure running "make check" on ppc64 for the first time.  
> >>>>>> Ideas?
> >>>>>>
> >>>>>> Stefan
> >>>>>>
> >>>>>> commit 682df581c65ed2c1b9e77093e332214ecaa1ee93
> >>>>>>
> >>>>>>   GTESTER check-qtest-ppc64
> >>>>>> Memory content inconsistency at 5af4000 first_byte = 1b last_byte = 1a
> >>>>>> current = 7c hit_edge = 1
> >>>>>> Memory content inconsistency at 5af5000 first_byte = 1b last_byte = 7c
> >>>>>> current = 1b hit_edge = 1
> >>>>>> Memory content inconsistency at 5e59000 first_byte = 1b last_byte = 1b
> >>>>>> current = 1a hit_edge = 1
> >>>>>> **
> >>>>>> ERROR:tests/postcopy-test.c:345:check_guests_ram: 'bad' should be FALSE
> >>>>>> GTester: last random seed: R02S9d79166a1ca7e21940a0f4b0b1255d5b
> >>>>>>
> >>>>>
> >>>>> Are you using KVM PR?
> >>>>>
> >>>>> it  was working fine with TCG and KVM HV.
> >>>>>
> >>>>> Apparently, USERFAULTFD doesn't work with KVM PR.
> >>>>>
> >>>>> I've already seen this kind of error with nested KVM on Power:
> >>>>> guest in guest with KVM PR in host.
> >>>>>
> >>>>> This problem was reported on IRC by Greg if I remember correctly (CC:)
> >>>>>
> >>>>
> >>>> Yeah I hit this when running make check in a PPC64 BE guest which
> >>>> has kvm_pr loaded. I did not find time to investigate though... I've
> >>>> switched to run make check on bare metal POWER7 instead.
> >>>
> >>> Right, it's POWER7 PPC64 BE with kvm_pr.
> >>>
> >>
> >> And you cannot install a PPC64 BE distro on this POWER7 host and use
> >> kvm_hv instead ?
> > 
> > Sure, I could get a non-kvm_pr environment.  I'm just concerned that
> > QEMU 2.8-rc0 is being tagged today and there is a POWER environment
> > where "make check" fails.
> > 
> > Is kvm_pr supported by QEMU?
> 
> Basically yes, it's just like Greg said in another mail, it does not get
> much attention these days.
> 
> > If it is supported then "make check" ought to pass.
> 
> OK, since nobody got a really, really good idea how to fix this so far:
> What about changing the QEMU test to use only tcg for now, so we've got
> a clean release with QEMU v2.8? And then afterwards, we can either fix
> kvm-pr in the kernel, or introduce some other mechanism to select
> whether the test should be run with KVM or not (either a detection of
> the KVM type, or an environment variable or something similar).

I'm OK if you want to do that for Power; I'd prefer it kept preferring KVM on
x86.

Dave

>  Thomas
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK