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

From: Christoph Hellwig
Date: Sat Sep 26 2020 - 03:51:34 EST


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.