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GET /api/1.0/patches/2198119/?format=api
{ "id": 2198119, "url": "http://patchwork.ozlabs.org/api/1.0/patches/2198119/?format=api", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/1.0/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20260219115530.2019498-7-vsementsov@yandex-team.ru>", "date": "2026-02-19T11:55:27", "name": "[v11,6/8] net/tap: support local migration with virtio-net", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "066e139b5787d5a9b0a799cfeac6541eaca0210b", "submitter": { "id": 84116, "url": "http://patchwork.ozlabs.org/api/1.0/people/84116/?format=api", "name": "Vladimir Sementsov-Ogievskiy", "email": "vsementsov@yandex-team.ru" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260219115530.2019498-7-vsementsov@yandex-team.ru/mbox/", "series": [ { "id": 492667, "url": "http://patchwork.ozlabs.org/api/1.0/series/492667/?format=api", "date": "2026-02-19T11:55:27", "name": "virtio-net: live-TAP local migration", "version": 11, "mbox": "http://patchwork.ozlabs.org/series/492667/mbox/" } ], "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2198119/checks/", "tags": {}, "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=yandex-team.ru header.i=@yandex-team.ru\n header.a=rsa-sha256 header.s=default header.b=vSiaFSFq;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)", "mail-nwsmtp-smtp-corp-main-34.sas.yp-c.yandex.net;\n dkim=pass header.i=@yandex-team.ru" ], "Received": [ "from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fGsKl5WkQz1xxQ\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 19 Feb 2026 22:56:26 +1100 (AEDT)", "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1vt2dO-0004Pw-5V; Thu, 19 Feb 2026 06:55:54 -0500", "from eggs.gnu.org ([2001:470:142:3::10])\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <vsementsov@yandex-team.ru>)\n id 1vt2dE-0004Nv-Vp\n for qemu-devel@nongnu.org; Thu, 19 Feb 2026 06:55:47 -0500", "from forwardcorp1b.mail.yandex.net ([178.154.239.136])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <vsementsov@yandex-team.ru>)\n id 1vt2dC-0006EI-Pu\n for qemu-devel@nongnu.org; Thu, 19 Feb 2026 06:55:44 -0500", "from mail-nwsmtp-smtp-corp-main-34.sas.yp-c.yandex.net\n (mail-nwsmtp-smtp-corp-main-34.sas.yp-c.yandex.net\n [IPv6:2a02:6b8:c24:fa2:0:640:41ee:0])\n by forwardcorp1b.mail.yandex.net (Yandex) with ESMTPS id DDEA6808BA;\n Thu, 19 Feb 2026 14:55:40 +0300 (MSK)", "from vsementsov-lin (unknown [2a02:6bf:8080:192::1:26])\n by mail-nwsmtp-smtp-corp-main-34.sas.yp-c.yandex.net (smtpcorp/Yandex) with\n ESMTPSA id VtZwpM4A6uQ0-wujyPL65; Thu, 19 Feb 2026 14:55:40 +0300" ], "Precedence": "bulk", "X-Yandex-Fwd": "1", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru;\n s=default; t=1771502140;\n bh=YKdHNL8F4xc0z/xXa7YTpcea+oVF1roRqyiwl/iJsKw=;\n h=Message-ID:Date:In-Reply-To:Cc:Subject:References:To:From;\n b=vSiaFSFqc93WijllvYcHbedmH0L6E4GvQbiJWTlohsaLiHpQaEvlA4D+eOW3UUTlT\n /9jv6Ry7CFcyTXdIDtOUwvHY7QwQQKwGppHj611Tj/SPgL1CFDv9LbE3bBgAkaZ5cq\n o7leUTlobuvRGSRUyXNCUcQ6hEskC7bwy+KJwPkQ=", "From": "Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>", "To": "jasowang@redhat.com,\n\tmst@redhat.com", "Cc": "thuth@redhat.com, armbru@redhat.com, eblake@redhat.com, farosas@suse.de,\n peterx@redhat.com, zhao1.liu@intel.com, wangyanan55@huawei.com,\n philmd@linaro.org, marcel.apfelbaum@gmail.com, eduardo@habkost.net,\n davydov-max@yandex-team.ru, qemu-devel@nongnu.org,\n vsementsov@yandex-team.ru, yc-core@yandex-team.ru, leiyang@redhat.com,\n raphael.s.norwitz@gmail.com, bchaney@akamai.com", "Subject": "[PATCH v11 6/8] net/tap: support local migration with virtio-net", "Date": "Thu, 19 Feb 2026 14:55:27 +0300", "Message-ID": "<20260219115530.2019498-7-vsementsov@yandex-team.ru>", "X-Mailer": "git-send-email 2.52.0", "In-Reply-To": "<20260219115530.2019498-1-vsementsov@yandex-team.ru>", "References": "<20260219115530.2019498-1-vsementsov@yandex-team.ru>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Received-SPF": "pass client-ip=178.154.239.136;\n envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1b.mail.yandex.net", "X-Spam_score_int": "-20", "X-Spam_score": "-2.1", "X-Spam_bar": "--", "X-Spam_report": "(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001,\n SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no", "X-Spam_action": "no action", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.29", "List-Id": "qemu development <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "Support transferring of TAP state (including open fd) through\nmigration stream as part of viritio-net \"local-migration\".\n\nAdd new option, incoming-fds, which should be set to true to\ntrigger new logic.\n\nSigned-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>\n---\n net/tap.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++-\n qapi/net.json | 6 +++-\n 2 files changed, 96 insertions(+), 2 deletions(-)", "diff": "diff --git a/net/tap.c b/net/tap.c\nindex 294ca61f8b..f6e4a36e97 100644\n--- a/net/tap.c\n+++ b/net/tap.c\n@@ -393,6 +393,65 @@ static VHostNetState *tap_get_vhost_net(NetClientState *nc)\n return s->vhost_net;\n }\n \n+static bool tap_is_wait_incoming(NetClientState *nc)\n+{\n+ TAPState *s = DO_UPCAST(TAPState, nc, nc);\n+ assert(nc->info->type == NET_CLIENT_DRIVER_TAP);\n+ return s->fd == -1;\n+}\n+\n+static int tap_pre_load(void *opaque)\n+{\n+ TAPState *s = opaque;\n+\n+ if (s->fd != -1) {\n+ error_report(\n+ \"TAP is already initialized and cannot receive incoming fd\");\n+ return -EINVAL;\n+ }\n+\n+ return 0;\n+}\n+\n+static bool tap_setup_vhost(TAPState *s, Error **errp);\n+\n+static int tap_post_load(void *opaque, int version_id)\n+{\n+ TAPState *s = opaque;\n+ Error *local_err = NULL;\n+\n+ tap_read_poll(s, true);\n+\n+ if (s->fd < 0) {\n+ return -1;\n+ }\n+\n+ if (!tap_setup_vhost(s, &local_err)) {\n+ error_prepend(&local_err,\n+ \"Failed to setup vhost during TAP post-load: \");\n+ error_report_err(local_err);\n+ return -1;\n+ }\n+\n+ return 0;\n+}\n+\n+static const VMStateDescription vmstate_tap = {\n+ .name = \"net-tap\",\n+ .pre_load = tap_pre_load,\n+ .post_load = tap_post_load,\n+ .fields = (const VMStateField[]) {\n+ VMSTATE_FD(fd, TAPState),\n+ VMSTATE_BOOL(using_vnet_hdr, TAPState),\n+ VMSTATE_BOOL(has_ufo, TAPState),\n+ VMSTATE_BOOL(has_uso, TAPState),\n+ VMSTATE_BOOL(has_tunnel, TAPState),\n+ VMSTATE_BOOL(enabled, TAPState),\n+ VMSTATE_UINT32(host_vnet_hdr_len, TAPState),\n+ VMSTATE_END_OF_LIST()\n+ }\n+};\n+\n /* fd support */\n \n static NetClientInfo net_tap_info = {\n@@ -412,7 +471,9 @@ static NetClientInfo net_tap_info = {\n .set_vnet_le = tap_set_vnet_le,\n .set_vnet_be = tap_set_vnet_be,\n .set_steering_ebpf = tap_set_steering_ebpf,\n+ .is_wait_incoming = tap_is_wait_incoming,\n .get_vhost_net = tap_get_vhost_net,\n+ .backend_vmsd = &vmstate_tap,\n };\n \n static TAPState *net_tap_fd_init(NetClientState *peer,\n@@ -905,6 +966,12 @@ int net_init_tap(const Netdev *netdev, const char *name,\n return -1;\n }\n \n+ if (tap->incoming_fds && (tap->fd || tap->fds || tap->helper)) {\n+ error_setg(errp, \"incoming-fds is incompatible with \"\n+ \"fd=, fds=, helper=\");\n+ return -1;\n+ }\n+\n queues = tap_parse_fds_and_queues(tap, &fds, errp);\n if (queues < 0) {\n return -1;\n@@ -923,7 +990,24 @@ int net_init_tap(const Netdev *netdev, const char *name,\n goto fail;\n }\n \n- if (fds) {\n+ if (tap->incoming_fds) {\n+ for (i = 0; i < queues; i++) {\n+ NetClientState *nc;\n+ TAPState *s;\n+\n+ nc = qemu_new_net_client(&net_tap_info, peer, \"tap\", name);\n+ qemu_set_info_str(nc, \"incoming\");\n+\n+ s = DO_UPCAST(TAPState, nc, nc);\n+ s->fd = -1;\n+ if (vhost_fds) {\n+ s->vhostfd = vhost_fds[i];\n+ s->vhost_busyloop_timeout = tap->has_poll_us ? tap->poll_us : 0;\n+ } else {\n+ s->vhostfd = -1;\n+ }\n+ }\n+ } else if (fds) {\n for (i = 0; i < queues; i++) {\n if (i == 0) {\n vnet_hdr = tap_probe_vnet_hdr(fds[i], errp);\n@@ -949,6 +1033,12 @@ int net_init_tap(const Netdev *netdev, const char *name,\n g_autofree char *downscript =\n tap_parse_script(tap->downscript, DEFAULT_NETWORK_DOWN_SCRIPT);\n \n+ if (tap->incoming_fds && (script || downscript)) {\n+ error_setg(errp,\n+ \"incoming-fds requires script=no and downscript=no\");\n+ return -1;\n+ }\n+\n if (tap->ifname) {\n pstrcpy(ifname, sizeof ifname, tap->ifname);\n } else {\ndiff --git a/qapi/net.json b/qapi/net.json\nindex 118bd34965..79f5ce9f43 100644\n--- a/qapi/net.json\n+++ b/qapi/net.json\n@@ -355,6 +355,9 @@\n # @poll-us: maximum number of microseconds that could be spent on busy\n # polling for tap (since 2.7)\n #\n+# @incoming-fds: do not open/connnect any resources, instead wait for\n+# TAP state from incoming migration stream. (Since 11.0)\n+#\n # Since: 1.2\n ##\n { 'struct': 'NetdevTapOptions',\n@@ -373,7 +376,8 @@\n '*vhostfds': 'str',\n '*vhostforce': 'bool',\n '*queues': 'uint32',\n- '*poll-us': 'uint32'} }\n+ '*poll-us': 'uint32',\n+ '*incoming-fds': 'bool' } }\n \n ##\n # @NetdevSocketOptions:\n", "prefixes": [ "v11", "6/8" ] }