From patchwork Thu Jul 20 18:14:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Eugenio Perez Martin X-Patchwork-Id: 13320973 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0D8C7EB64DA for ; Thu, 20 Jul 2023 18:16:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qMYBk-00057w-3l; Thu, 20 Jul 2023 14:15:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qMYBX-0004N6-Np for qemu-devel@nongnu.org; Thu, 20 Jul 2023 14:15:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qMYBU-0003Mi-9t for qemu-devel@nongnu.org; Thu, 20 Jul 2023 14:15:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689876927; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6AnXRkfbPBY2lKGkgKhB/5jrIYEC5iVGXI+KaHqNwxg=; b=MhbzljXydb+rrAXm9U3hOvXibuYddf1KfW/R4bhWc+29+4oYV3I9MKlI+PDi42oTVocWxN +6KoWU9wqsJr394Ah9peIDGoFWs0+if997n+llzWIyHp7ufNIlJKbhdn5Qy1VjZCI91alW ZZI4CbF7anyEk2IpC6meO1Gpz0tZU0s= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-433-HN_1A3gbP9Ok9goyrbYUbQ-1; Thu, 20 Jul 2023 14:15:21 -0400 X-MC-Unique: HN_1A3gbP9Ok9goyrbYUbQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BF80E38025EA; Thu, 20 Jul 2023 18:15:20 +0000 (UTC) Received: from eperezma.remote.csb (unknown [10.39.193.122]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6E3B32166B25; Thu, 20 Jul 2023 18:15:19 +0000 (UTC) From: =?utf-8?q?Eugenio_P=C3=A9rez?= To: qemu-devel@nongnu.org Cc: yvugenfi@redhat.com, =?utf-8?q?Eugenio_P=C3=A9rez?= , si-wei.liu@oracle.com, Jason Wang , "Michael S. Tsirkin" , Dragos Tatulea , Shannon Nelson Subject: [RFC PATCH 11/12] vdpa: use SVQ to stall dataplane while NIC state is being restored Date: Thu, 20 Jul 2023 20:14:58 +0200 Message-Id: <20230720181459.607008-12-eperezma@redhat.com> In-Reply-To: <20230720181459.607008-1-eperezma@redhat.com> References: <20230720181459.607008-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eperezma@redhat.com; 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Some dynamic state of a virtio-net vDPA devices is restored from CVQ in the event of a live migration. However, dataplane needs to be disabled so the NIC does not receive buffers in the invalid ring. As a default method to achieve it, let's offer a shadow vring with 0 avail idx. As a fallback method, we will enable dataplane vqs later, as proposed previously. Signed-off-by: Eugenio Pérez --- net/vhost-vdpa.c | 49 +++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 44 insertions(+), 5 deletions(-) diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c index af83de92f8..e14ae48f23 100644 --- a/net/vhost-vdpa.c +++ b/net/vhost-vdpa.c @@ -338,10 +338,25 @@ static int vhost_vdpa_net_data_start(NetClientState *nc) { VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc); struct vhost_vdpa *v = &s->vhost_vdpa; + bool has_cvq = v->dev->vq_index_end % 2; assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); - if (s->always_svq || + if (has_cvq && (v->dev->features & VIRTIO_F_RING_RESET)) { + /* + * Offer a fake vring to the device while the state is restored + * through CVQ. That way, the guest will not see packets in unexpected + * queues. + * + * This will be undone after loading all state through CVQ, at + * vhost_vdpa_net_load. + * + * TODO: Future optimizations may skip some SVQ setup and teardown, + * like set the right kick and call fd or doorbell maps directly, and + * the iova tree. + */ + v->shadow_vqs_enabled = true; + } else if (s->always_svq || migration_is_setup_or_active(migrate_get_current()->state)) { v->shadow_vqs_enabled = true; v->shadow_data = true; @@ -738,10 +753,34 @@ static int vhost_vdpa_net_load(NetClientState *nc) return r; } - for (int i = 0; i < v->dev->vq_index; ++i) { - r = vhost_vdpa_set_vring_ready(v, i); - if (unlikely(r)) { - return r; + if (v->dev->features & VIRTIO_F_RING_RESET && !s->always_svq && + !migration_is_setup_or_active(migrate_get_current()->state)) { + NICState *nic = qemu_get_nic(s->nc.peer); + int queue_pairs = n->multiqueue ? n->max_queue_pairs : 1; + + for (int i = 0; i < queue_pairs; ++i) { + NetClientState *ncs = qemu_get_peer(nic->ncs, i); + VhostVDPAState *s_i = DO_UPCAST(VhostVDPAState, nc, ncs); + + for (int j = 0; j < 2; ++j) { + vhost_net_virtqueue_reset(v->dev->vdev, ncs->peer, j); + } + + s_i->vhost_vdpa.shadow_vqs_enabled = false; + + for (int j = 0; j < 2; ++j) { + r = vhost_net_virtqueue_restart(v->dev->vdev, ncs->peer, j); + if (unlikely(r < 0)) { + return r; + } + } + } + } else { + for (int i = 0; i < v->dev->vq_index; ++i) { + r = vhost_vdpa_set_vring_ready(v, i); + if (unlikely(r)) { + return r; + } } }