Re: [PATCH 4/5] misc: vop: set VIRTIO_F_ACCESS_PLATFORM for nocoherent platform

[Christoph Hellwig]

On Sun, Sep 27, 2020 at 08:05:07AM +0000, Sherry Sun wrote:
> Hi Christoph,
> 
> > On Fri, Sep 25, 2020 at 03:26:29PM +0800, Sherry Sun wrote:
> > > Set VIRTIO_F_ACCESS_PLATFORM feature for nocoherent platform, since it
> > > needs the DMA API for virtio.
> > 
> > Given that VOP is a plug-in PCIe card VIRTIO_F_ACCESS_PLATFORM must
> > always be set, as the DMA mapping details are not something the virtio
> > implementation decides on, but the host PCIe/iommu implementation.
> 
> So do you mean that we should remove the check, and set VIRTIO_F_ACCESS_PLATFORM feature directly?

Yes.  In a separate prep patch.