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

[Philippe Mathieu-Daudé]

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/