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GET /api/patches/2194230/?format=api
{ "id": 2194230, "url": "http://patchwork.ozlabs.org/api/patches/2194230/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260207134728.1495932-12-lulu@redhat.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/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": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260207134728.1495932-12-lulu@redhat.com>", "list_archive_url": null, "date": "2026-02-07T13:47:28", "name": "[12/12] net/filter-mirror: keep mirroring while stopped", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "5e75e7d05f0c2784c88521fe21e9e8b1b8f36617", "submitter": { "id": 78960, "url": "http://patchwork.ozlabs.org/api/people/78960/?format=api", "name": "Cindy Lu", "email": "lulu@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260207134728.1495932-12-lulu@redhat.com/mbox/", "series": [ { "id": 491379, "url": "http://patchwork.ozlabs.org/api/series/491379/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=491379", "date": "2026-02-07T13:47:17", "name": "[01/12] net: introduce read_poll/write_poll", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/491379/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2194230/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2194230/checks/", "tags": {}, "related": [], "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=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=IV5lEaf/;\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)" ], "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 4f7XQB3SXwz1xtV\n\tfor <incoming@patchwork.ozlabs.org>; Sun, 08 Feb 2026 00:49:54 +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 1voigp-0004jT-Ub; Sat, 07 Feb 2026 08:49:36 -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 <lulu@redhat.com>) id 1voiga-0003t2-AZ\n for qemu-devel@nongnu.org; Sat, 07 Feb 2026 08:49:23 -0500", "from us-smtp-delivery-124.mimecast.com ([170.10.129.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <lulu@redhat.com>) id 1voigY-0003IZ-Iy\n for qemu-devel@nongnu.org; Sat, 07 Feb 2026 08:49:20 -0500", "from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-113-zGtJ3BM1OF6Wrjf-WIMqXA-1; Sat,\n 07 Feb 2026 08:49:16 -0500", "from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 3F6B31956096; Sat, 7 Feb 2026 13:49:15 +0000 (UTC)", "from S2.redhat.com (unknown [10.72.112.15])\n by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id 2467F18004AD; Sat, 7 Feb 2026 13:49:11 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1770472157;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=2bUnt00SkKmzXgkXF9v5vh1BRVBWlK52wAXmRAjVjC8=;\n b=IV5lEaf/K/i0hG/2K1kpjj+/eO2yG2FjU9GBrCrNnJIxkohqN/Ais9tnmQiXL1+RCbn/QK\n +H3mihYN4y1qNBllLjHb+BZGFCR1KppMf7OCBoEhAKRYBXLcFJc2vQd6L+b9id5vc6dSRh\n oppPNp/WFoVeXD5EiW0xJuURHqSHD9g=", "X-MC-Unique": "zGtJ3BM1OF6Wrjf-WIMqXA-1", "X-Mimecast-MFC-AGG-ID": "zGtJ3BM1OF6Wrjf-WIMqXA_1770472155", "From": "Cindy Lu <lulu@redhat.com>", "To": "lulu@redhat.com, mst@redhat.com, jasowang@redhat.com, zhangckid@gmail.com,\n lizhijian@fujitsu.com, qemu-devel@nongnu.org", "Subject": "[PATCH 12/12] net/filter-mirror: keep mirroring while stopped", "Date": "Sat, 7 Feb 2026 21:47:28 +0800", "Message-ID": "<20260207134728.1495932-12-lulu@redhat.com>", "In-Reply-To": "<20260207134728.1495932-1-lulu@redhat.com>", "References": "<20260207134728.1495932-1-lulu@redhat.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Scanned-By": "MIMEDefang 3.4.1 on 10.30.177.93", "Received-SPF": "pass client-ip=170.10.129.124; envelope-from=lulu@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com", "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, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001,\n RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001,\n 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", "Precedence": "list", "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": "During migration pre-switchover the VM runstate is stopped, which can cause tap read_poll to be disabled (qemu_send_packet_async() returns 0) and incoming tap frames stop reaching the redirector/mirror filter.\n\nRe-enable tap read_poll when swredir is turned on while stopped, and allow the redirector outdev path to keep draining packets while stopped by adding a per-NetClientState allow_send_when_stopped bit used by qemu_can_send_packet().\n\nSigned-off-by: Cindy Lu <lulu@redhat.com>\n---\n include/net/net.h | 6 ++++++\n net/filter-mirror.c | 49 +++++++++++++++++++++++++++++++++++++--------\n net/net.c | 10 ++++++++-\n 3 files changed, 56 insertions(+), 9 deletions(-)", "diff": "diff --git a/include/net/net.h b/include/net/net.h\nindex d2b2e6fc44..bde052acbb 100644\n--- a/include/net/net.h\n+++ b/include/net/net.h\n@@ -126,6 +126,12 @@ struct NetClientState {\n char *name;\n char info_str[256];\n unsigned receive_disabled : 1;\n+ /*\n+ * Allow this sender to keep draining packets while VM is stopped.\n+ * Used by COLO-style pre-switchover mirroring, where netfilter needs to\n+ * see incoming tap frames even when runstate is not running.\n+ */\n+ unsigned allow_send_when_stopped:1;\n NetClientDestructor *destructor;\n unsigned int queue_index;\n unsigned rxfilter_notify_enabled:1;\ndiff --git a/net/filter-mirror.c b/net/filter-mirror.c\nindex de32028246..ad99bebec6 100644\n--- a/net/filter-mirror.c\n+++ b/net/filter-mirror.c\n@@ -268,6 +268,10 @@ static void filter_redirector_cleanup(NetFilterState *nf)\n qemu_chr_fe_deinit(&s->chr_in, false);\n qemu_chr_fe_deinit(&s->chr_out, false);\n qemu_del_vm_change_state_handler(s->vmsentry);\n+\n+ if (nf->netdev) {\n+ nf->netdev->allow_send_when_stopped = 0;\n+ }\n }\n \n static void filter_mirror_setup(NetFilterState *nf, Error **errp)\n@@ -322,6 +326,27 @@ static void redirector_rs_finalize(SocketReadState *rs)\n redirector_to_filter(nf, QEMU_NET_PACKET_FLAG_RAW, buf, len);\n }\n \n+static void\n+filter_redirector_refresh_allow_send_when_stopped(NetFilterState *nf)\n+{\n+ MirrorState *s = FILTER_REDIRECTOR(nf);\n+ NetClientState *nc = nf->netdev;\n+\n+ if (!nc) {\n+ return;\n+ }\n+\n+ /*\n+ * Allow sending when stopped if enable_when_stopped is set and we have\n+ * an outdev. This must be independent of nf->on (status) so that packets\n+ * can still flow through the filter chain to other filters even when this\n+ * redirector is disabled. Otherwise, tap_send() will disable read_poll\n+ * when qemu_can_send_packet() returns false, preventing further packet\n+ * processing.\n+ */\n+ nc->allow_send_when_stopped = (s->enable_when_stopped && s->outdev);\n+}\n+\n static void filter_redirector_vm_state_change(void *opaque, bool running,\n RunState state)\n {\n@@ -409,24 +434,30 @@ static void filter_redirector_setup(NetFilterState *nf, Error **errp)\n filter_redirector_vm_state_change, nf);\n \n filter_redirector_maybe_enable_read_poll(nf);\n+\n+ filter_redirector_refresh_allow_send_when_stopped(nf);\n }\n \n static void filter_redirector_status_changed(NetFilterState *nf, Error **errp)\n {\n MirrorState *s = FILTER_REDIRECTOR(nf);\n \n- if (!s->indev) {\n- return;\n+ if (s->indev) {\n+ if (nf->on) {\n+ qemu_chr_fe_set_handlers(&s->chr_in, redirector_chr_can_read,\n+ redirector_chr_read, redirector_chr_event,\n+ NULL, nf, NULL, true);\n+ } else {\n+ qemu_chr_fe_set_handlers(&s->chr_in, NULL, NULL, NULL,\n+ NULL, NULL, NULL, true);\n+ }\n }\n \n if (nf->on) {\n- qemu_chr_fe_set_handlers(&s->chr_in, redirector_chr_can_read,\n- redirector_chr_read, redirector_chr_event,\n- NULL, nf, NULL, true);\n- } else {\n- qemu_chr_fe_set_handlers(&s->chr_in, NULL, NULL, NULL,\n- NULL, NULL, NULL, true);\n+ filter_redirector_maybe_enable_read_poll(nf);\n }\n+\n+ filter_redirector_refresh_allow_send_when_stopped(nf);\n }\n \n static char *filter_redirector_get_indev(Object *obj, Error **errp)\n@@ -538,6 +569,8 @@ static void filter_redirector_set_enable_when_stopped(Object *obj,\n if (value) {\n filter_redirector_maybe_enable_read_poll(nf);\n }\n+\n+ filter_redirector_refresh_allow_send_when_stopped(nf);\n }\n \n static void filter_mirror_class_init(ObjectClass *oc, const void *data)\ndiff --git a/net/net.c b/net/net.c\nindex b15f4db65e..06f54eebb4 100644\n--- a/net/net.c\n+++ b/net/net.c\n@@ -632,7 +632,7 @@ int qemu_can_send_packet(NetClientState *sender)\n {\n int vm_running = runstate_is_running();\n \n- if (!vm_running) {\n+ if (!vm_running && !sender->allow_send_when_stopped) {\n return 0;\n }\n \n@@ -640,6 +640,14 @@ int qemu_can_send_packet(NetClientState *sender)\n return 1;\n }\n \n+ /*\n+ * When VM is stopped (e.g. migration pre-switchover), allow draining tap\n+ * packets so netfilters (redirector/mirror) can operate.\n+ */\n+ if (!vm_running && sender->allow_send_when_stopped) {\n+ return 1;\n+ }\n+\n return qemu_can_receive_packet(sender->peer);\n }\n \n", "prefixes": [ "12/12" ] }