From: Jason Wang <jasowang@redhat.com>
To: wexu@redhat.com, qemu-devel@nongnu.org
Cc: tiwei.bie@intel.com, jfreimann@redhat.com, maxime.coquelin@redhat.com
Subject: Re: [Qemu-devel] [[RFC v3 09/12] virtio-net: fill head desc after done all in a chain
Date: Mon, 15 Oct 2018 15:45:46 +0800 [thread overview]
Message-ID: <fb04c68b-024b-5be8-00ea-e558f9ae0d12@redhat.com> (raw)
In-Reply-To: <1539266915-15216-10-git-send-email-wexu@redhat.com>
On 2018年10月11日 22:08, wexu@redhat.com wrote:
> From: Wei Xu <wexu@redhat.com>
>
> With the support of marking a descriptor used/unused in 'flags'
> field for 1.1, the current way of filling a chained descriptors
> does not work since driver side may get the wrong 'num_buffer'
> information in case of the head descriptor has been filled in
> while the subsequent ones are still in processing in device side.
>
> This patch fills the head one after done all the others one.
>
> Signed-off-by: Wei Xu <wexu@redhat.com>
> ---
> hw/net/virtio-net.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 4bdd5b8..186c86cd2 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1198,6 +1198,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
> struct virtio_net_hdr_mrg_rxbuf mhdr;
> unsigned mhdr_cnt = 0;
> size_t offset, i, guest_offset;
> + VirtQueueElement head;
> + int head_len = 0;
>
> if (!virtio_net_can_receive(nc)) {
> return -1;
> @@ -1275,7 +1277,13 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
> }
>
> /* signal other side */
> - virtqueue_fill(q->rx_vq, elem, total, i++);
> + if (i == 0) {
> + head_len = total;
> + head = *elem;
> + } else {
> + virtqueue_fill(q->rx_vq, elem, len, i);
> + }
> + i++;
> g_free(elem);
> }
>
> @@ -1286,6 +1294,7 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
> &mhdr.num_buffers, sizeof mhdr.num_buffers);
> }
>
> + virtqueue_fill(q->rx_vq, &head, head_len, 0);
It's not a good idea to fix API in device implementation. Let's
introduce new API and fix it there.
E.g virtqueue_fill_n() and update the flag of first elem at the last step.
Thanks
> virtqueue_flush(q->rx_vq, i);
> virtio_notify(vdev, q->rx_vq);
>
next prev parent reply other threads:[~2018-10-15 7:46 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 14:08 [Qemu-devel] [RFC v3 00/12] packed ring virtio-net userspace backend support wexu
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 01/12] virtio: introduce packed ring definitions wexu
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 02/12] virtio: redefine structure & memory cache for packed ring wexu
2018-10-15 3:03 ` Jason Wang
2018-10-15 7:26 ` Wei Xu
2018-10-15 8:03 ` Jason Wang
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 03/12] virtio: init " wexu
2018-10-15 3:10 ` Jason Wang
2018-10-15 7:09 ` Wei Xu
2018-10-15 7:54 ` Jason Wang
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 04/12] virtio: init wrap counter " wexu
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 05/12] virtio: init and desc empty check " wexu
2018-10-15 3:18 ` Jason Wang
2018-10-15 7:04 ` Wei Xu
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 06/12] virtio: get avail bytes " wexu
2018-10-15 3:47 ` Jason Wang
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 07/12] virtio: fill/flush/pop " wexu
2018-10-15 6:14 ` Jason Wang
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 08/12] virtio: event suppression support " wexu
2018-10-15 6:55 ` Jason Wang
2018-10-15 6:59 ` Jason Wang
2018-10-15 8:20 ` Wei Xu
2018-10-15 9:11 ` Jason Wang
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 09/12] virtio-net: fill head desc after done all in a chain wexu
2018-10-15 7:45 ` Jason Wang [this message]
2018-10-15 8:03 ` Wei Xu
2018-10-15 8:05 ` Jason Wang
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 10/12] virtio: packed ring feature bit for userspace backend wexu
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 11/12] virtio: enable packed ring via a new command line wexu
2018-10-11 14:08 ` [Qemu-devel] [[RFC v3 12/12] virtio: feature vhost-net support for packed ring wexu
2018-10-15 7:50 ` Jason Wang
2018-10-15 8:11 ` Wei Xu
2018-11-21 13:03 ` Maxime Coquelin
2018-11-22 3:46 ` Wei Xu
2018-11-21 14:39 ` [Qemu-devel] [RFC v3 00/12] packed ring virtio-net userspace backend support Tiwei Bie
2018-11-22 3:43 ` Wei Xu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=fb04c68b-024b-5be8-00ea-e558f9ae0d12@redhat.com \
--to=jasowang@redhat.com \
--cc=jfreimann@redhat.com \
--cc=maxime.coquelin@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=tiwei.bie@intel.com \
--cc=wexu@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).