Re: [Qemu-devel] [PATCH v6 0/8] ARM virt: ACPI memory hotplug support

[Auger Eric <eric.auger@redhat.com>]

Hi Peter,

On 7/2/19 1:46 PM, Peter Maydell wrote:
> On Tue, 2 Jul 2019 at 12:07, Igor Mammedov <imammedo@redhat.com> wrote:
>>
>> On Tue, 25 Jun 2019 13:14:13 +0100
>> Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:
>>
>>> This series is an attempt to provide device memory hotplug support
>>> on ARM virt platform. This is based on Eric's recent works here[1]
>>> and carries some of the pc-dimm related patches dropped from his
>>> series.
>>>
>>> The kernel support for arm64 memory hot add was added recently by
>>> Robin and hence the guest kernel should be => 5.0-rc1.
>>>
>>> NVDIM support is not included currently as we still have an unresolved
>>> issue while hot adding NVDIMM[2]. However NVDIMM cold plug patches
>>> can be included, but not done for now, for keeping it simple.
>>>
>>> This makes use of GED device to sent hotplug ACPI events to the
>>> Guest. GED code is based on Nemu. Thanks to the efforts of Samuel and
>>> Sebastien to add the hardware-reduced support to Nemu using GED
>>> device[3]. (Please shout if I got the author/signed-off wrong for
>>> those patches or missed any names).
>>>
>>> This is sanity tested on a HiSilicon ARM64 platform and appreciate
>>> any further testing.
>>
>> There are several things I'd fix/amend but it's nothing that couldn't
>> be done on top as bugfixes (I'll comment later on specific issues).
>>
>> However as a whole from ACPI and memory hotplug POV series looks more
>> or less ready for merging.
>>
>> I've asked Eric to test migration (I'm quite not sure about that part),
>> (CCed David)so on condition it works:
>>
>>   Reviewed-by: Igor Mammedov <imammedo@redhat.com>
> 
> If we want to get this into 4.1 I'll need somebody to do a respin
> with all the relevant fixes pretty soon (ie within a day or two,
> and that is pushing it because really it's missed the freeze
> deadline already). It might be easier just to let it go into 4.2
> instead...

OK so after those late attempts to get it in, I agree with you. If it
missed the deadline already then let's stick to the process and try to
get this just after 4.1.

I have just checked migration and it fails between a qemu 4.1 and qemu
4.0 with

"qemu-system-aarch64: Unknown savevm section or instance 'acpi-ged' 0.
Make sure that your current VM setup matches your saved VM setup,
including any hotplugged devices
qemu-system-aarch64: load of migration failed: Invalid argument"

so we would need to have a no_acpi_dev class field to avoid using the
GED device < 4.1 I think.

+ troubles with the DSDT ref files / bios-tables-test.c to be fixed.

Thanks

Eric
> 
> thanks
> -- PMM
>