Re: [RFC virtio-next 0/4] Introduce CAIF Virtio and reversed Vrings

[Rusty Russell <rusty@rustcorp.com.au>]

Sjur Brændeland <sjur@brendeland.net> writes:
> Zero-Copy data transport on the modem is primary goal for CAIF Virtio.
> In order to achieve Zero-Copy the direction of the Virtio rings are
> flipped in the RX direction. So we have implemented the Virtio
> access-function similar to what is found in vhost.c.

So, this adds another host-side virtqueue implementation.

Can we combine them together conveniently?  You pulled out more stuff
into vring.h which is a start, but it's a bit overloaded.

Perhaps we should separate the common fields into struct vring, and use
it to build:

        struct vring_guest {
                struct vring vr;
                u16 last_used_idx;
        };

        struct vring_host {
                struct vring vr;
                u16 last_avail_idx;
        };

I haven't looked closely at vhost to see what it wants, but I would
think we could share more code.

Cheers,
Rusty.