Re: [PATCH v11 0/3] vhost-user,udp: Handle multiple iovec entries per virtqueue element

[Stefano Brivio <sbrivio@redhat.com>]

On Wed, 20 May 2026 11:55:23 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> Some virtio-net drivers (notably iPXE) provide descriptors where the
> vnet header and the frame payload are in separate buffers, resulting in
> two iovec entries per virtqueue element.  Currently, the RX (host to
> guest) path assumes a single iovec per element, which triggers:
> 
>   ASSERTION FAILED in virtqueue_map_desc (virtio.c:403):
>       num_sg < max_num_sg
> 
> This series reworks the UDP vhost-user receive path to support multiple
> iovec entries per element, fixing the iPXE crash.
> 
> This series only addresses the UDP path.  TCP vhost-user will be
> updated to use multi-iov elements in a subsequent series.
> 
> v11:
> - Rebase on master
> - use sizeof(*uh) instead of sizeof(struct udphdr) in
>   udp_tap_prepare()
> - improve @payload doc in udp_vu_sock_recv()
> - add R-b from David

Applied.

-- 
Stefano