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[209.51.188.17]) by mx.google.com with ESMTPS id ay31-20020a05622a229f00b003a7e514c7fcsi1017377qtb.600.2022.12.05.02.11.50 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 05 Dec 2022 02:11:50 -0800 (PST) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=OEeKb8Nl; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p28Bf-0002G0-As; Mon, 05 Dec 2022 04:54:59 -0500 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 1p28BT-0001xx-9s for qemu-devel@nongnu.org; Mon, 05 Dec 2022 04:54:48 -0500 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 1p28BP-0006wx-SL for qemu-devel@nongnu.org; Mon, 05 Dec 2022 04:54:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670234083; 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=wv3mQ50z7ELRb+0PxbMX5qClEbrZYnNWGDwG8BSgdlg=; b=OEeKb8NlIf+HwalK72K5FStBYR0UwDUb0NOL8qCxadf+miCWeuBX9/DNV5qfgTTb0TGr/S W+Ix9t0EiWndbNLQ9QTFVam4CdpN+Xwpa2/ZEKr6sI1ehv+6WmSuzTTH6T7eQXRIH4tHMC sLdPq2EhQJckNbVGVOj9CmDtlVQOAXw= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-47-SDGhJug8OKyBI7Not_p4Fg-1; Mon, 05 Dec 2022 04:54:39 -0500 X-MC-Unique: SDGhJug8OKyBI7Not_p4Fg-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 DD957101A52A; Mon, 5 Dec 2022 09:54:37 +0000 (UTC) Received: from secure.mitica (unknown [10.39.194.135]) by smtp.corp.redhat.com (Postfix) with ESMTP id AE8AE2166B30; Mon, 5 Dec 2022 09:54:30 +0000 (UTC) From: Juan Quintela To: qemu-devel@nongnu.org Cc: Fam Zheng , Thomas Huth , Viresh Kumar , Kevin Wolf , Mathieu Poirier , Laurent Vivier , Eric Blake , Richard Henderson , Raphael Norwitz , Stefan Hajnoczi , Juan Quintela , virtio-fs@redhat.com, =?utf-8?q?Alex_Benn=C3=A9e?= , Christian Borntraeger , "Gonglei (Arei)" , qemu-block@nongnu.org, Xiaojuan Yang , Thomas Huth , Ilya Leoshkevich , Eduardo Habkost , Gerd Hoffmann , "Dr. David Alan Gilbert" , Alex Williamson , Eric Farman , Halil Pasic , Peter Maydell , Vladimir Sementsov-Ogievskiy , Jason Wang , Laurent Vivier , Song Gao , qemu-s390x@nongnu.org, Pavel Dovgalyuk , Klaus Jensen , John Snow , Michael Tokarev , qemu-arm@nongnu.org, Paolo Bonzini , "Michael S. Tsirkin" , Keith Busch , David Hildenbrand , qemu-trivial@nongnu.org, Hanna Reitz Subject: [PATCH v2 15/51] hw/virtio: generalise CHR_EVENT_CLOSED handling Date: Mon, 5 Dec 2022 10:51:52 +0100 Message-Id: <20221205095228.1314-16-quintela@redhat.com> In-Reply-To: <20221205095228.1314-1-quintela@redhat.com> References: <20221205095228.1314-1-quintela@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=quintela@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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org From: Alex Bennée ..and use for both virtio-user-blk and virtio-user-gpio. This avoids the circular close by deferring shutdown due to disconnection until a later point. virtio-user-blk already had this mechanism in place so generalise it as a vhost-user helper function and use for both blk and gpio devices. While we are at it we also fix up vhost-user-gpio to re-establish the event handler after close down so we can reconnect later. Signed-off-by: Alex Bennée Reviewed-by: Michael S. Tsirkin Reviewed-by: Raphael Norwitz Message-Id: <20221130112439.2527228-5-alex.bennee@linaro.org> Signed-off-by: Michael S. Tsirkin --- include/hw/virtio/vhost-user.h | 18 +++++++++ hw/block/vhost-user-blk.c | 41 +++----------------- hw/virtio/vhost-user-gpio.c | 11 +++++- hw/virtio/vhost-user.c | 71 ++++++++++++++++++++++++++++++++++ 4 files changed, 104 insertions(+), 37 deletions(-) diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h index c6e693cd3f..191216a74f 100644 --- a/include/hw/virtio/vhost-user.h +++ b/include/hw/virtio/vhost-user.h @@ -68,4 +68,22 @@ bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp); */ void vhost_user_cleanup(VhostUserState *user); +/** + * vhost_user_async_close() - cleanup vhost-user post connection drop + * @d: DeviceState for the associated device (passed to callback) + * @chardev: the CharBackend associated with the connection + * @vhost: the common vhost device + * @cb: the user callback function to complete the clean-up + * + * This function is used to handle the shutdown of a vhost-user + * connection to a backend. We handle this centrally to make sure we + * do all the steps and handle potential races due to VM shutdowns. + * Once the connection is disabled we call a backhalf to ensure + */ +typedef void (*vu_async_close_fn)(DeviceState *cb); + +void vhost_user_async_close(DeviceState *d, + CharBackend *chardev, struct vhost_dev *vhost, + vu_async_close_fn cb); + #endif diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index 1177064631..aff4d2b8cb 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -369,17 +369,10 @@ static void vhost_user_blk_disconnect(DeviceState *dev) vhost_user_blk_stop(vdev); vhost_dev_cleanup(&s->dev); -} -static void vhost_user_blk_chr_closed_bh(void *opaque) -{ - DeviceState *dev = opaque; - VirtIODevice *vdev = VIRTIO_DEVICE(dev); - VHostUserBlk *s = VHOST_USER_BLK(vdev); - - vhost_user_blk_disconnect(dev); + /* Re-instate the event handler for new connections */ qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event, - NULL, opaque, NULL, true); + NULL, dev, NULL, true); } static void vhost_user_blk_event(void *opaque, QEMUChrEvent event) @@ -398,33 +391,9 @@ static void vhost_user_blk_event(void *opaque, QEMUChrEvent event) } break; case CHR_EVENT_CLOSED: - if (!runstate_check(RUN_STATE_SHUTDOWN)) { - /* - * A close event may happen during a read/write, but vhost - * code assumes the vhost_dev remains setup, so delay the - * stop & clear. - */ - AioContext *ctx = qemu_get_current_aio_context(); - - qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL, - NULL, NULL, false); - aio_bh_schedule_oneshot(ctx, vhost_user_blk_chr_closed_bh, opaque); - - /* - * Move vhost device to the stopped state. The vhost-user device - * will be clean up and disconnected in BH. This can be useful in - * the vhost migration code. If disconnect was caught there is an - * option for the general vhost code to get the dev state without - * knowing its type (in this case vhost-user). - * - * FIXME: this is sketchy to be reaching into vhost_dev - * now because we are forcing something that implies we - * have executed vhost_dev_stop() but that won't happen - * until vhost_user_blk_stop() gets called from the bh. - * Really this state check should be tracked locally. - */ - s->dev.started = false; - } + /* defer close until later to avoid circular close */ + vhost_user_async_close(dev, &s->chardev, &s->dev, + vhost_user_blk_disconnect); break; case CHR_EVENT_BREAK: case CHR_EVENT_MUX_IN: diff --git a/hw/virtio/vhost-user-gpio.c b/hw/virtio/vhost-user-gpio.c index be9be08b4c..b7b82a1099 100644 --- a/hw/virtio/vhost-user-gpio.c +++ b/hw/virtio/vhost-user-gpio.c @@ -233,6 +233,8 @@ static int vu_gpio_connect(DeviceState *dev, Error **errp) return 0; } +static void vu_gpio_event(void *opaque, QEMUChrEvent event); + static void vu_gpio_disconnect(DeviceState *dev) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); @@ -245,6 +247,11 @@ static void vu_gpio_disconnect(DeviceState *dev) vu_gpio_stop(vdev); vhost_dev_cleanup(&gpio->vhost_dev); + + /* Re-instate the event handler for new connections */ + qemu_chr_fe_set_handlers(&gpio->chardev, + NULL, NULL, vu_gpio_event, + NULL, dev, NULL, true); } static void vu_gpio_event(void *opaque, QEMUChrEvent event) @@ -262,7 +269,9 @@ static void vu_gpio_event(void *opaque, QEMUChrEvent event) } break; case CHR_EVENT_CLOSED: - vu_gpio_disconnect(dev); + /* defer close until later to avoid circular close */ + vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev, + vu_gpio_disconnect); break; case CHR_EVENT_BREAK: case CHR_EVENT_MUX_IN: diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index abe23d4ebe..8f635844af 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -21,6 +21,7 @@ #include "qemu/error-report.h" #include "qemu/main-loop.h" #include "qemu/sockets.h" +#include "sysemu/runstate.h" #include "sysemu/cryptodev.h" #include "migration/migration.h" #include "migration/postcopy-ram.h" @@ -2670,6 +2671,76 @@ void vhost_user_cleanup(VhostUserState *user) user->chr = NULL; } + +typedef struct { + vu_async_close_fn cb; + DeviceState *dev; + CharBackend *cd; + struct vhost_dev *vhost; +} VhostAsyncCallback; + +static void vhost_user_async_close_bh(void *opaque) +{ + VhostAsyncCallback *data = opaque; + struct vhost_dev *vhost = data->vhost; + + /* + * If the vhost_dev has been cleared in the meantime there is + * nothing left to do as some other path has completed the + * cleanup. + */ + if (vhost->vdev) { + data->cb(data->dev); + } + + g_free(data); +} + +/* + * We only schedule the work if the machine is running. If suspended + * we want to keep all the in-flight data as is for migration + * purposes. + */ +void vhost_user_async_close(DeviceState *d, + CharBackend *chardev, struct vhost_dev *vhost, + vu_async_close_fn cb) +{ + if (!runstate_check(RUN_STATE_SHUTDOWN)) { + /* + * A close event may happen during a read/write, but vhost + * code assumes the vhost_dev remains setup, so delay the + * stop & clear. + */ + AioContext *ctx = qemu_get_current_aio_context(); + VhostAsyncCallback *data = g_new0(VhostAsyncCallback, 1); + + /* Save data for the callback */ + data->cb = cb; + data->dev = d; + data->cd = chardev; + data->vhost = vhost; + + /* Disable any further notifications on the chardev */ + qemu_chr_fe_set_handlers(chardev, + NULL, NULL, NULL, NULL, NULL, NULL, + false); + + aio_bh_schedule_oneshot(ctx, vhost_user_async_close_bh, data); + + /* + * Move vhost device to the stopped state. The vhost-user device + * will be clean up and disconnected in BH. This can be useful in + * the vhost migration code. If disconnect was caught there is an + * option for the general vhost code to get the dev state without + * knowing its type (in this case vhost-user). + * + * Note if the vhost device is fully cleared by the time we + * execute the bottom half we won't continue with the cleanup. + */ + vhost->started = false; + } +} + static int vhost_user_dev_start(struct vhost_dev *dev, bool started) { if (!virtio_has_feature(dev->protocol_features,