Re: [PATCH manager/qemu-server 0/8] Add API and UI for custom CPU models

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

Am 12.03.26 um 9:40 AM schrieb Arthur Bied-Charreton:
> This is picked up from an old series [0] by Stefan Reiter.
> 
> As of before this series, the only way to create custom CPU models is by
> editing `/etc/pve/virtual-guest/cpu-models.conf` manually.
> 
> This can be cumbersome for a few reasons, e.g., due to the fact that flags
> misconfigurations are only caught when starting the VM.
> 
> `cpu-flags` endpoint:
> The `cpu-flags` endpoint previously returned a list of hardcoded flags,
> which is both non-exhaustive (some flags I should be able to set are missing),
> and partly incorrect (some flags my host(s) do not support set are returned).
> This is limiting and can lead to misconfigurations. The updated endpoint
> intersects all flags QEMU accepts as `-cpu` arguments with all flags the host
> hardware/emulation actually supports. This way, if I am able to set a flag in
> the UI, I can be confident that the VM will actually be able to start.
> 
> Custom CPU model CRUD functionality:
> Expose CRUD endpoints and UI flow to interact with `cpu-models.conf`. For each
> flag, show a list of the cluster nodes supporting it, and only expose flags that
> at least one node supports to avoid misconfigurations. Filter flags by
> acceleration type (KVM/TCG).
> 
> [0] https://lore.proxmox.com/pve-devel/20211028114150.3245864-1-s.reiter@proxmox.com/

With a pre-existing, manually added model:

[I] root@pve9a1 ~# cat /etc/pve/virtual-guest/cpu-models.conf
cpu-model: nested-for-wsl
	flags +svm
	hidden 1
	hv-vendor-id AuthenticAMD
	reported-model EPYC

When opening it up in the UI, the editor seems to immediately detect a
change, i.e. the OK button is clickable and when I click it, I get the
following error:

Parameter verification failed. (400)
flags: value does not match the regex pattern

It seems to be because of the 'svm' flag not being in the flags grid.
Since users might've already added such models manually, it would be
nice if it would work. Maybe list the unknown flags in the grid without
description?