Re: [PATCH v2 0/7] virtio-mem: s390 support

David Hildenbrand
2024-10-14T19:18:03Z

On 14.10.24 20:56, Heiko Carstens wrote:
> On Mon, Oct 14, 2024 at 04:46:12PM +0200, David Hildenbrand wrote:
>> Let's finally add s390 support for virtio-mem; my last RFC was sent
>> 4 years ago, and a lot changed in the meantime.
>>
>> The latest QEMU series is available at [1], which contains some more
>> details and a usage example on s390 (last patch).
>>
>> There is not too much in here: The biggest part is querying a new diag(500)
>> STORAGE_LIMIT hypercall to obtain the proper "max_physmem_end".
>>
>> The last two patches are not strictly required but certainly nice-to-have.
>>
>> Note that -- in contrast to standby memory -- virtio-mem memory must be
>> configured to be automatically onlined as soon as hotplugged. The easiest
>> approach is using the "memhp_default_state=" kernel parameter or by using
>> proper udev rules. More details can be found at [2].
>>
>> I have reviving+upstreaming a systemd service to handle configuring
>> that on my todo list, but for some reason I keep getting distracted ...
>>
>> I tested various things, including:
>> * Various memory hotplug/hotunplug combinations
>> * Device hotplug/hotunplug
>> * /proc/iomem output
>> * reboot
>> * kexec
>> * kdump: make sure we don't hotplug memory
>>
>> One remaining work item is kdump support for virtio-mem memory. This will
>> be sent out separately once initial support landed.
>
> Besides the open kdump question, which I think is quite important, how
> is this supposed to go upstream?

MST suggested via the s390 tree in v1.

>
> This could go via s390, however in any case this needs reviews and/or
> Acks from kvm folks.

Yes, hoping there will be some review (there was some on the QEMU series).

--
Cheers,

David / dhildenb