Re: [PATCH v2 00/14] s390x: virtio-mem support

[Thomas Huth <thuth@redhat.com>]

On 12/12/2024 22.52, David Hildenbrand wrote:
> On 13.11.24 15:46, David Hildenbrand wrote:
>> On 08.10.24 12:54, David Hildenbrand wrote:
>>> Based on current master.
>>>
>>> There is really not much left to do on s390x, because virtio-mem already
>>> implements most things we need today (e.g., early-migration,
>>> unplugged-inaccessible). The biggest part of this series is just doing what
>>> we do with virtio-pci, wiring it up in the machine hotplug handler and ...
>>> well, messing with the physical memory layout where we can now exceed
>>> initial RAM size and have sparsity (memory holes).
>>>
>>> I tested a lot of things, including:
>>>    * Memory hotplug/unplug
>>>    * Device hotplug/unplug
>>>    * System resets / reboots
>>>    * Migrate to/from file (including storage attributes under KVM)
>>>    * Basic live migration
>>>    * Basic postcopy live migration
>>>
>>> More details on how to use it on s390x -- which is pretty much how
>>> we use it on other architectures, except
>>> s/virtio-mem-pci/virtio-mem-ccw/ --- is in the last patch.
>>>
>>> This series introduces a new diag(500) "STORAGE LIMIT" subcode that will
>>> be documented in the kernel and at [2] once this+kernel part go upstream.
>>>
>>> There are not many s390x-specific virtio-mem future work items, except:
>>> * Storage attribute migration might be improved
>>> * We might want to reset storage attributes of unplugged memory
>>>     (might or might not be required for upcoming page table reclaim in
>>>      Linux; TBD)
>>>
>>> The Linux driver is available at [3].
>>>
>>> [1] https://lkml.kernel.org/r/20240906101658.514470-1-pbonzini@redhat.com
>>> [2] https://gitlab.com/davidhildenbrand/s390x-os-virt-spec
>>> [3] https://lkml.kernel.org/r/20240910191541.2179655-6-david@redhat.com
>>
>> Gentle ping (and thanks to Thomas for the review!).
>>
>> I assume the kernel portion will go upstream in the next merge window.
>> I'd like get the QEMU parts merged soon after that.
>>
>> 9.2 is going to get released in roughly one month, so there is still time.
> 
> In the meantime, 9.2 was released. I don't have any changes planned. Series 
> still applies to current master, I'll do a quick test tomorrow.
> 
>>
>> @Thomas, this is mostly s390x stuff, so I guess it should go through the
>> s390x tree? But I could also take this through my "memory devices" tree.
> 
> @Thomas, any thoughts?

I'm fine either way - feel free to put it into your tree, otherwise I'll 
pick it up likely sometime next week.

  Thomas