Re: [PATCH v8] vpci: Add resizable bar support

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

On Fri, Feb 14, 2025 at 09:01:12AM +0000, Chen, Jiqian wrote:
> On 2025/2/14 16:39, Roger Pau Monné wrote:
> > On Fri, Feb 14, 2025 at 08:22:39AM +0000, Chen, Jiqian wrote:
> >> On 2025/2/14 16:18, Oleksii Kurochko wrote:
> >>>
> >>> On 2/14/25 8:35 AM, Jan Beulich wrote:
> >>>> On 14.02.2025 04:32, Chen, Jiqian wrote:
> >>>>> On 2025/2/11 17:21, Roger Pau Monné wrote:
> >>>>>> On Tue, Feb 11, 2025 at 10:22:57AM +0800, Jiqian Chen wrote:
> >>>>>>> Some devices, like AMDGPU, support resizable bar capability,
> >>>>>>> but vpci of Xen doesn't support this feature, so they fail
> >>>>>>> to resize bars and then cause probing failure.
> >>>>>>>
> >>>>>>> According to PCIe spec, each bar that supports resizing has
> >>>>>>> two registers, PCI_REBAR_CAP and PCI_REBAR_CTRL. So, add
> >>>>>>> handlers to support resizing the size of BARs.
> >>>>>>>
> >>>>>>> Note that Xen will only trap PCI_REBAR_CTRL, as PCI_REBAR_CAP
> >>>>>>> is read-only register and the hardware domain already gets
> >>>>>>> access to it without needing any setup.
> >>>>>>>
> >>>>>>> Signed-off-by: Jiqian Chen <Jiqian.Chen@xxxxxxx>
> >>>>>> Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> >>>>> Thank you!
> >>>>> May I know whether this can be merged in Xen version 4.20?
> >>>
> >>> It would be better to merge it after the Xen 4.20 release.
> >>> (It will happen in the next 2 weeks).
> >> Got it. Thank you for reply.
> > 
> > Could you also add an entry to the CHANGELOG.md file to note that
> > ReBAR is now supported on PVH dom0?
> Sure, I will add it in next version. And I think I need to wait until there 
> is a 4.21.0 entry.

Yes, I don't recall if the entry for 4.21 is created as part of the
4.20 release process, or the first commit to introduce a new feature
also adds the boilerplate 4.21 section.

> In SUPPORT.md, do I need to change the sentence " * PCI SR-IOV and Resizable 
> BARs." to " * PCI SR-IOV. "?

Oh, indeed, I forgot about that one.  Yes please, also update
SUPPORT.md.

Thanks, Roger.