From nobody Fri Nov 7 10:32:48 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (209.51.188.17 [209.51.188.17]) by mx.zohomail.com with SMTPS id 1550119104845929.206218073694; Wed, 13 Feb 2019 20:38:24 -0800 (PST) Received: from localhost ([127.0.0.1]:39886 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gu8mw-0008U4-R1 for importer@patchew.org; Wed, 13 Feb 2019 23:38:18 -0500 Received: from eggs.gnu.org ([209.51.188.92]:41498) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gu8dH-0001MZ-E9 for qemu-devel@nongnu.org; Wed, 13 Feb 2019 23:28:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gu8dF-00059z-1K for qemu-devel@nongnu.org; Wed, 13 Feb 2019 23:28:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48312) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gu8dE-0004gU-Nu for qemu-devel@nongnu.org; Wed, 13 Feb 2019 23:28:16 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 98CB3C01DE02; Thu, 14 Feb 2019 04:27:59 +0000 (UTC) Received: from dell-per430-12.lab.eng.pek2.redhat.com (dell-per430-12.lab.eng.pek2.redhat.com [10.73.196.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2FA0C5D962; Thu, 14 Feb 2019 04:27:56 +0000 (UTC) From: wexu@redhat.com To: qemu-devel@nongnu.org Date: Wed, 13 Feb 2019 23:26:40 -0500 Message-Id: <1550118402-4057-10-git-send-email-wexu@redhat.com> In-Reply-To: <1550118402-4057-1-git-send-email-wexu@redhat.com> References: <1550118402-4057-1-git-send-email-wexu@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 14 Feb 2019 04:27:59 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v4 09/11] virtio-net: update the head descriptor in a chain lastly X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tiwei.bie@intel.com, mst@redhat.com, jasowang@redhat.com, jfreiman@redhat.com, maxime.coquelin@redhat.com, wexu@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Wei Xu This is a helper for packed ring. To support packed ring, the head descriptor in a chain should be updated lastly since no 'avail_idx' like in packed ring to explicitly tell the driver side that all payload is ready after having done the chain, so the head is always visible immediately. This patch fills the header after done all the other ones. Signed-off-by: Wei Xu --- 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 3f319ef..330abea 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1251,6 +1251,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState = *nc, const uint8_t *buf, struct virtio_net_hdr_mrg_rxbuf mhdr; unsigned mhdr_cnt =3D 0; size_t offset, i, guest_offset; + VirtQueueElement head; + int head_len =3D 0; =20 if (!virtio_net_can_receive(nc)) { return -1; @@ -1328,7 +1330,13 @@ static ssize_t virtio_net_receive_rcu(NetClientState= *nc, const uint8_t *buf, } =20 /* signal other side */ - virtqueue_fill(q->rx_vq, elem, total, i++); + if (i =3D=3D 0) { + head_len =3D total; + head =3D *elem; + } else { + virtqueue_fill(q->rx_vq, elem, len, i); + } + i++; g_free(elem); } =20 @@ -1339,6 +1347,7 @@ static ssize_t virtio_net_receive_rcu(NetClientState = *nc, const uint8_t *buf, &mhdr.num_buffers, sizeof mhdr.num_buffers); } =20 + virtqueue_fill(q->rx_vq, &head, head_len, 0); virtqueue_flush(q->rx_vq, i); virtio_notify(vdev, q->rx_vq); =20 --=20 1.8.3.1