Re: [RFC PATCH 6/6] arm/xen: Assign xen-virtio DMA ops for virtio devices in Xen guests

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Fri, Apr 15, 2022 at 03:02:45PM -0700, Stefano Stabellini wrote:
> This makes sense overall. Considering that the swiotlb-xen case and the
> virtio case are mutually exclusive, I would write it like this:

Curious question:  Why can't the same grant scheme also be used for
non-virtio devices?  I really hate having virtio hooks in the arch
dma code.  Why can't Xen just say in DT/ACPI that grants can be used
for a given device?