[Avocado-devel] [PATCH 12/21] hw/arm: Let the machine be the owner of the system memory

[Philippe Mathieu-Daudé]

Cc'ing avocado-devel for test idea.

On 10/21/19 4:57 PM, Dr. David Alan Gilbert wrote:
> * Philippe Mathieu-Daudé (philmd at redhat.com) wrote:
>> Cc'ing Paolo/David.
>>
>> On 10/21/19 11:39 AM, Peter Maydell wrote:
>>> On Mon, 21 Oct 2019 at 10:34, Philippe Mathieu-Daudé <philmd at redhat.com> wrote:
>>>>
>>>> On 10/21/19 11:22 AM, Peter Maydell wrote:
>>>>> On Mon, 21 Oct 2019 at 00:01, Philippe Mathieu-Daudé <philmd at redhat.com> wrote:
>>>>>>
>>>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd at redhat.com>
>>>>>> ---
>>>>>
>>>>>>    hw/arm/virt.c             | 2 +-
>>>>>
>>>>> I think from a quick code scan that this is ok, but did
>>>>> you test that migration compat from old to new still works?
>>>>> I vaguely recall that there are some cases when adding an
>>>>> owner to a memory region changes the name string used for
>>>>> identifying the ramblock in migration.
>>>>
>>>> It seems to still works:
>>>>
>>>> $ make check-qtest-aarch64 V=1
>>>
>>>> This test migrate the virt machine.
>>>>
>>>> Is this enough?
>>>
>>> No, you need to test migration from a QEMU binary without
>>> this patchset to a QEMU binary that has it. Otherwise you're
>>> only checking that the new version can migrate from itself
>>> to itself. I find the easiest way to test this is just to
>>> use the 'savevm' command to save a state snapshot to a
>>> qcow2 disk image while running the old binary, and then run
>>> 'loadvm' with the new binary and check it restored OK.
>>
>> I did not think if this case.
>>
>> I followed your blog post [*] and tested the migration works OK.
>>
>> Paolo, now thinking about regular testing, we should add this testing to
>> patchew too. Something like:
>>
>> - when mainstream/master is updated, patchew build QEMU (it should be
>> already mostly ccached) and generate some vm dumps with 'savevm'.
>>
>> - build/test the series
>>
>> - if series succeeded testing, run 'loadvm' tests
>>
>> [*] https://translatedcode.wordpress.com/2015/07/06/tricks-for-debugging-qemu-savevm-snapshots/
> 
> Avocado certainly already has an option for specifying source and
> destination qemu separately; I've used that for testing
> cross version in the past.
> 
> The challenge is finding a command line/set of devices for each
> architecture that's expected to be stable.
> You want a command line with as big a set of devices as possible (for
> coverage) yet really is tied to machine type.
> 
> Dave
> 
> --
> Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK
>