Re: [pve-devel] [PATCH pve-qemu 1/1] patch: add 0001-add-cpu-models-x86-64-abi.patch

[Fiona Ebner <f.ebner@proxmox.com>]

Am 17.05.23 um 10:25 schrieb DERUMIER, Alexandre:
> Le mercredi 17 mai 2023 à 09:46 +0200, Fiona Ebner a écrit :
>> Am 17.05.23 um 09:02 schrieb Alexandre Derumier:
>>> Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
>>> ---
>>>  .../pve/0001-add-cpu-models-x86-64-abi.patch  | 272
>>> ++++++++++++++++++
>>>  debian/patches/series                         |   1 +
>>>  2 files changed, 273 insertions(+)
>>>  create mode 100644 debian/patches/pve/0001-add-cpu-models-x86-64-
>>> abi.patch
>>>
>>
>> Do we really need this? Can't we just define these as custom CPU
>> models
>> in qemu-server? I'd really prefer to not pick up such patches if not
>> necessary. Ideally, we reduce divergence from upstream QEMU rather
>> than
>> increase it. 
> yes sure we can do it in qemu-server, with simply setting flags in
> command line.
> 
> It was more by security to not forgot a cpu flag.
> 
> 
>> Since the patch was never applied, what other solution did
>> upstream or libvirt go for?
> The end of the discussion was that it could be done userland
> like qemu-server ;)

Yes, let's just introduce a custom CPU model there, which will be the
new UI default.

> I'll rework the patch series.
> 
> (BTW, what do you think about bumping the default model ? is it ok for
> you ?)
> 

Yes, I do think it should be done, because most currently in-use CPUs
should be fine with x86-64-abi2 and it's not nice to users if the
defaults don't work out-of-the-box[0]. And other people can just select
kvm64. Changing the default in the UI for new VMs should not lead to any
breakage and your series does just that. Still, something we'll want to
mention in the PVE 8 release notes to not catch people off guard.

[0]:
https://forum.proxmox.com/threads/kernel-panic-when-creating-vms-centos-9-stream-iso.104656/