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

[Thomas Huth]

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).

 Thomas