Re: [PATCH V1 6/6] arm/xen: Assign xen-grant DMA ops for xen-grant DMA devices

[Oleksandr]

On 23.04.22 19:42, Christoph Hellwig wrote:

Hello Christoph

> On Fri, Apr 22, 2022 at 07:51:03PM +0300, Oleksandr Tyshchenko wrote:
> >   static inline void xen_setup_dma_ops(struct device *dev)
> >   {
> >   #ifdef CONFIG_XEN
> > -	if (xen_swiotlb_detect())
> > +	if (arch_has_restricted_virtio_memory_access() &&
> > +			xen_is_grant_dma_device(dev))
> > +		xen_grant_setup_dma_ops(dev);
> > +	else if (xen_swiotlb_detect())
> I don't think that arch_has_restricted_virtio_memory_access
> check should be there as it still is a bit of a layering violation.

Well, I will remove it then (and update commit description).

For virtualized but non-virtio devices, it is not needed at all. For the 
virtio devices, this check is already present at 
virtio.c:virtio_features_ok()



>
--
Regards,

Oleksandr Tyshchenko