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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8395194d-6c9d-4324-a475-1b856707a729@redhat.com>
Date: Fri, 25 Oct 2024 12:54:31 +0200
From: David Hildenbrand <david@...hat.com>
To: Claudio Imbrenda <imbrenda@...ux.ibm.com>,
 Heiko Carstens <hca@...ux.ibm.com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 linux-s390@...r.kernel.org, virtualization@...ts.linux.dev,
 linux-doc@...r.kernel.org, kvm@...r.kernel.org,
 Vasily Gorbik <gor@...ux.ibm.com>, Alexander Gordeev
 <agordeev@...ux.ibm.com>, Christian Borntraeger <borntraeger@...ux.ibm.com>,
 Sven Schnelle <svens@...ux.ibm.com>, Thomas Huth <thuth@...hat.com>,
 Cornelia Huck <cohuck@...hat.com>, Janosch Frank <frankja@...ux.ibm.com>,
 "Michael S. Tsirkin" <mst@...hat.com>, Jason Wang <jasowang@...hat.com>,
 Xuan Zhuo <xuanzhuo@...ux.alibaba.com>, Eugenio Pérez
 <eperezma@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>,
 Jonathan Corbet <corbet@....net>
Subject: Re: [PATCH v2 0/7] virtio-mem: s390 support

On 15.10.24 09:57, Claudio Imbrenda wrote:
> On Mon, 14 Oct 2024 20:56:59 +0200
> Heiko Carstens <hca@...ux.ibm.com> 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?
>>
>> This could go via s390, however in any case this needs reviews and/or
>> Acks from kvm folks.
> 
> we're working on it :)

I'll be sending a v3 later today, and a v1 of kdump support (which 
involves a bunch of changes to fs/proc/vmcore.c and virtio-mem) separately.

-- 
Cheers,

David / dhildenb