Re: [RFC PATCH 1/3] content: Add VIRTIO_F_SWIOTLB to negotiate use of SWIOTLB bounce buffers

[Christoph Hellwig]

On Wed, Apr 02, 2025 at 12:04:45PM +0100, David Woodhouse wrote:
> Define a VIRTIO_F_SWIOTLB feature which allows the device and driver to
> agree on the use of the SWIOTLB, if present. This enables the device to
> refuse to operate further if the driver does not support the SWIOTLB
> requirement expressed in the device-tree.

This makes no sense whatsoever.  Swiotlb is a Linux guest implementation
detail, virtio is a transport protocol.  Mixing them in the same spec
doesn't even compute.  Please describe the actual on the wire semantics
you want, and don't use the term swiotlb.