Re: [PATCH v1] CHANGELOG.md: Mention PCI passthrough for HVM domUs

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Mar 13, 2025 at 08:42:25AM +0100, Jan Beulich wrote:
> On 12.03.2025 17:36, Roger Pau Monné wrote:
> > On Wed, Mar 12, 2025 at 09:51:09AM +0100, Jan Beulich wrote:
> >> On 12.03.2025 05:02, Jiqian Chen wrote:
> >>> PCI passthrough is already supported for HVM domUs when dom0 is PVH
> >>> on x86. The last related patch on Qemu side was merged after Xen4.20
> >>> release. So mention this feature in Xen4.21 entry.
> >>>
> >>> Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
> >>> ---
> >>>  CHANGELOG.md | 1 +
> >>>  1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/CHANGELOG.md b/CHANGELOG.md
> >>> index 7201c484f899..b6de9b72ea7a 100644
> >>> --- a/CHANGELOG.md
> >>> +++ b/CHANGELOG.md
> >>> @@ -12,6 +12,7 @@ The format is based on [Keep a 
> >>> Changelog](https://keepachangelog.com/en/1.0.0/)
> >>>   - On x86:
> >>>     - Option to attempt to fixup p2m page-faults on PVH dom0.
> >>>     - Resizable BARs is supported for PVH dom0.
> >>> +   - Support PCI passthrough for HVM domUs when dom0 is PVH.
> >>
> >> Aren't we still in need of SR-IOV support in order to make such an
> >> unconditional statement?
> > 
> > I view SR-IOV as kind of orthogonal to this: SR-IOV is not
> > supported at all on PVH dom0, so it's not just pass through, but the
> > capability itself that won't work as expected when using such devices.
> 
> Hmm, yes and no. No in so far as I as someone who simply wants to use Xen
> would read the above statement as indicating full pass-through support.
> Which first and foremost includes the passing through of VFs.

Maybe we can clarify somehow that SR-IOV devices are still not
supported on a PVH dom0:

 - Support PCI passthrough for HVM domUs when dom0 is PVH (note
   SR-IOV capability usage is not yet supported on PVH dom0).

In any case we should likely wait for:

https://lore.kernel.org/xen-devel/20250308001711.18746-1-jason.andryuk@xxxxxxx/

To be committed?

Thanks, Roger.