Re: [RFC PATCH 2/6] xen/public: arch-arm: reserve resources for virtio-pci

[Julien Grall <julien@xxxxxxx>]

On 16/11/2023 15:26, Stewart Hildebrand wrote:
> On 11/16/23 10:12, Julien Grall wrote:
> > Hi Volodymyr,
> >
> > On 16/11/2023 15:07, Volodymyr Babchuk wrote:
> > > With my vPCI patch series in place, hypervisor itself assigns BDFs for
> > > passed-through devices. Toolstack needs to get this information to know
> > > which BDFs are free and can be used by virtio-pci.
> > It sounds a bit odd to let the hypervisor to assign the BDFs. At least because there 
> > might be case where you want to specific vBDF (for instance this is the case with some 
> > intel graphic cards). This should be the toolstack job to say "I want to assign the 
> > pBDF to this vBDF".
> Keep in mind we are also supporting dom0less PCI passthrough.
Right, but even with that in mind, I expect the Device-Tree to provide 
the details where a given PCI is assigned.
You could have logic for assigning the BDF automagically. But that 
should be part of dom0less, not deep into the vPCI code.
Cheers,

--
Julien Grall