From patchwork Tue Jul 11 15:52:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309008 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 29955EB64DC for ; Tue, 11 Jul 2023 15:53:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfN-0000cq-IX; Tue, 11 Jul 2023 11:52:41 -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 1qJFfL-0000cb-UK for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:40 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qJFfK-0001h6-BN for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090757; 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=qyoQ/2+6R/ip2NcA77dLWUg2JHvuG7jjdTygBaSGwm4=; b=WD44CszwUPT6dZsjGEB8LXxNOUO+yVC45eHRSuQfgLBZt3lbhGJ+eHhmkpEGPkpjgpGqVN vehzeGLvnEH8HPKjN9lvQtMGKkUxBHuglVA2la1NcQITMsPY5BPjbn2+FINcUf8lKSN6C5 naLZPICxREi8DzS7tICwFsuy1skfZs0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [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-362-D6zZoyUDNSKRNtrEQlljew-1; Tue, 11 Jul 2023 11:52:35 -0400 X-MC-Unique: D6zZoyUDNSKRNtrEQlljew-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 207A53814950 for ; Tue, 11 Jul 2023 15:52:35 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AC450C09A09; Tue, 11 Jul 2023 15:52:34 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 1/6] vhost-user.rst: Add suspend/resume Date: Tue, 11 Jul 2023 17:52:23 +0200 Message-ID: <20230711155230.64277-2-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@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 When stopping the VM, qemu wants all devices to fully cease any operation, too. Currently, we can only have vhost-user back-ends stop processing vrings, but not background operations. Add the SUSPEND and RESUME commands from vDPA, which allow the front-end (qemu) to tell back-ends to cease all operations, including those running in the background. qemu's current work-around for this is to reset the back-end instead of suspending it, which will not work for back-ends that have internal state that must be preserved across e.g. stop/cont. Note that the given specification requires the back-end to delay processing kicks (i.e. starting vrings) until the device is resumed, instead of requiring the front-end not to send kicks while suspended. qemu starts devices (and would just resume them) only when the VM is in a running state, so it would be difficult to have qemu delay kicks until the device is resumed, which is why this patch specifies handling of kicks as it does. Signed-off-by: Hanna Czenczek --- docs/interop/vhost-user.rst | 35 +++++++++++++++++++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-) diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index 5a070adbc1..ac6be34c4c 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -381,6 +381,10 @@ readable) on the descriptor specified by ``VHOST_USER_SET_VRING_KICK`` or receiving the in-band message ``VHOST_USER_VRING_KICK`` if negotiated, and stop ring upon receiving ``VHOST_USER_GET_VRING_BASE``. +While the back-end is suspended (via ``VHOST_USER_SUSPEND``), it must +never process rings, and thus also delay handling kicks until the +back-end is resumed again. + Rings can be enabled or disabled by ``VHOST_USER_SET_VRING_ENABLE``. If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the @@ -479,8 +483,9 @@ supplied by ``VhostUserLog``. ancillary data, it may be used to inform the front-end that the log has been modified. -Once the source has finished migration, rings will be stopped by the -source. No further update must be done before rings are restarted. +Once the source has finished migration, the device will be suspended and +its rings will be stopped by the source. No further update must be done +before the device and its rings are resumed. In postcopy migration the back-end is started before all the memory has been received from the source host, and care must be taken to avoid @@ -885,6 +890,7 @@ Protocol features #define VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS 15 #define VHOST_USER_PROTOCOL_F_STATUS 16 #define VHOST_USER_PROTOCOL_F_XEN_MMAP 17 + #define VHOST_USER_PROTOCOL_F_SUSPEND 18 Front-end message types ----------------------- @@ -1440,6 +1446,31 @@ Front-end message types query the back-end for its device status as defined in the Virtio specification. +``VHOST_USER_SUSPEND`` + :id: 41 + :equivalent ioctl: VHOST_VDPA_SUSPEND + :request payload: N/A + :reply payload: N/A + + When the ``VHOST_USER_PROTOCOL_F_SUSPEND`` protocol feature has been + successfully negotiated, this message is submitted by the front-end to + have the back-end cease all operations except for handling vhost-user + requests. The back-end must stop processing all virt queues, and it + must not perform any background operations. It may not resume until a + subsequent ``VHOST_USER_RESUME`` call. + +``VHOST_USER_RESUME`` + :id: 42 + :equivalent ioctl: VHOST_VDPA_RESUME + :request payload: N/A + :reply payload: N/A + + When the ``VHOST_USER_PROTOCOL_F_SUSPEND`` protocol feature has been + successfully negotiated, this message is submitted by the front-end to + allow the back-end to resume operations after having been suspended + before. The back-end must again begin processing rings that are not + stopped, and it may resume background operations. + Back-end message types ---------------------- From patchwork Tue Jul 11 15:52:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309013 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 426A4EB64DC for ; Tue, 11 Jul 2023 15:54:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfQ-0000dl-Ke; Tue, 11 Jul 2023 11:52:44 -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 1qJFfO-0000d7-CN for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qJFfM-0001hS-Sg for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090760; 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=O7XJ3VYkhKbviFV13JlcB2ntASgDMEpG1mgMeRrDu64=; b=LDT2yUNR+wyU9bPyCtUTWjWscGFr2WBqoC7QHy54+Tu+/L4BLsYJPeAPxq0WiL595D1mT6 xEXq0ybFqvxpSzAHB9sL3x3MefU5MXSlkwN8SVc/BAKYFdqltOhUiowTgCjS9EPBiybC1M WYs4O9aSGJXKyVlS/ss9e48TJZYQ+Iw= 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-524-da2mod3wP3euBMnAgcRAbA-1; Tue, 11 Jul 2023 11:52:37 -0400 X-MC-Unique: da2mod3wP3euBMnAgcRAbA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 438621043AC5 for ; Tue, 11 Jul 2023 15:52:37 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D87E51121315; Tue, 11 Jul 2023 15:52:36 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 2/6] vhost-vdpa: Move vhost_vdpa_reset_status() up Date: Tue, 11 Jul 2023 17:52:24 +0200 Message-ID: <20230711155230.64277-3-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@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 The next commit is going to have vhost_vdpa_dev_start() call this, so move it up to have the declaration where we are going to need it. Signed-off-by: Hanna Czenczek Reviewed-by: Stefan Hajnoczi --- hw/virtio/vhost-vdpa.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index 42f2a4bae9..7b7dee468e 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -1286,6 +1286,20 @@ static void vhost_vdpa_suspend(struct vhost_dev *dev) vhost_vdpa_reset_device(dev); } +static void vhost_vdpa_reset_status(struct vhost_dev *dev) +{ + struct vhost_vdpa *v = dev->opaque; + + if (dev->vq_index + dev->nvqs != dev->vq_index_end) { + return; + } + + vhost_vdpa_reset_device(dev); + vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE | + VIRTIO_CONFIG_S_DRIVER); + memory_listener_unregister(&v->listener); +} + static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started) { struct vhost_vdpa *v = dev->opaque; @@ -1323,20 +1337,6 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started) return 0; } -static void vhost_vdpa_reset_status(struct vhost_dev *dev) -{ - struct vhost_vdpa *v = dev->opaque; - - if (dev->vq_index + dev->nvqs != dev->vq_index_end) { - return; - } - - vhost_vdpa_reset_device(dev); - vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE | - VIRTIO_CONFIG_S_DRIVER); - memory_listener_unregister(&v->listener); -} - static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base, struct vhost_log *log) { From patchwork Tue Jul 11 15:52:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309011 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 50365EB64DC for ; Tue, 11 Jul 2023 15:53:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfR-0000e4-5Z; Tue, 11 Jul 2023 11:52:46 -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 1qJFfP-0000db-Bz for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qJFfN-0001hm-PT for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090761; 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=Vp6pWpdnR3eKs5VasVSM9LNR1XXQyd2OrdGAiDMmfg4=; b=N7QVyKzNVnNHECnLHjTHNEnOh91mCwtB4oAuS4UnL7FKP/7F7s9fbcXd50TrB+SzqQVx9P 6rVdO9/LD7+ti4Fe911vGK0Ahd3HfCoyZiB+pWx75L1v7FjIOBiSN5tleSkx02a+rYFeca 1GuCoL7RHitGA560LfzydKiBmjizC6g= 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-324-_q7LsmWTOXOCPFEjzWZitA-1; Tue, 11 Jul 2023 11:52:39 -0400 X-MC-Unique: _q7LsmWTOXOCPFEjzWZitA-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 46089185A78F for ; Tue, 11 Jul 2023 15:52:39 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AE2B92166B26; Tue, 11 Jul 2023 15:52:38 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 3/6] vhost: Do not reset suspended devices on stop Date: Tue, 11 Jul 2023 17:52:25 +0200 Message-ID: <20230711155230.64277-4-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@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 Move the `suspended` field from vhost_vdpa into the global vhost_dev struct, so vhost_dev_stop() can check whether the back-end has been suspended by `vhost_ops->vhost_dev_start(hdev, false)`. If it has, there is no need to reset it; the reset is just a fall-back to stop device operations for back-ends that do not support suspend. Unfortunately, for vDPA specifically, RESUME is not yet implemented, so when the device is re-started, we still have to do the reset to have it un-suspend. Signed-off-by: Hanna Czenczek Reviewed-by: Stefan Hajnoczi --- include/hw/virtio/vhost-vdpa.h | 2 -- include/hw/virtio/vhost.h | 8 ++++++++ hw/virtio/vhost-vdpa.c | 11 +++++++---- hw/virtio/vhost.c | 8 +++++++- 4 files changed, 22 insertions(+), 7 deletions(-) diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h index e64bfc7f98..72c3686b7f 100644 --- a/include/hw/virtio/vhost-vdpa.h +++ b/include/hw/virtio/vhost-vdpa.h @@ -42,8 +42,6 @@ typedef struct vhost_vdpa { bool shadow_vqs_enabled; /* Vdpa must send shadow addresses as IOTLB key for data queues, not GPA */ bool shadow_data; - /* Device suspended successfully */ - bool suspended; /* IOVA mapping used by the Shadow Virtqueue */ VhostIOVATree *iova_tree; GPtrArray *shadow_vqs; diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index 6a173cb9fa..69bf59d630 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -120,6 +120,14 @@ struct vhost_dev { uint64_t backend_cap; /* @started: is the vhost device started? */ bool started; + /** + * @suspended: Whether the vhost device is currently suspended. Set + * and reset by implementations (vhost-user, vhost-vdpa, ...), which + * are supposed to automatically suspend/resume in their + * vhost_dev_start handlers as required. Must also be cleared when + * the device is reset. + */ + bool suspended; bool log_enabled; uint64_t log_size; Error *migration_blocker; diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index 7b7dee468e..f7fd19a203 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -858,13 +858,12 @@ static int vhost_vdpa_get_device_id(struct vhost_dev *dev, static int vhost_vdpa_reset_device(struct vhost_dev *dev) { - struct vhost_vdpa *v = dev->opaque; int ret; uint8_t status = 0; ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &status); trace_vhost_vdpa_reset_device(dev); - v->suspended = false; + dev->suspended = false; return ret; } @@ -1278,7 +1277,7 @@ static void vhost_vdpa_suspend(struct vhost_dev *dev) if (unlikely(r)) { error_report("Cannot suspend: %s(%d)", g_strerror(errno), errno); } else { - v->suspended = true; + dev->suspended = true; return; } } @@ -1313,6 +1312,10 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started) return -1; } vhost_vdpa_set_vring_ready(dev); + if (dev->suspended) { + /* TODO: When RESUME is available, use it instead of resetting */ + vhost_vdpa_reset_status(dev); + } } else { vhost_vdpa_suspend(dev); vhost_vdpa_svqs_stop(dev); @@ -1400,7 +1403,7 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev, return 0; } - if (!v->suspended) { + if (!dev->suspended) { /* * Cannot trust in value returned by device, let vhost recover used * idx from guest. diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index abf0d03c8d..2e28e58da7 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -2059,7 +2059,13 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings) hdev->vqs + i, hdev->vq_index + i); } - if (hdev->vhost_ops->vhost_reset_status) { + + /* + * If we failed to successfully stop the device via SUSPEND (should have + * been attempted by `vhost_dev_start(hdev, false)`), reset it to stop it. + * Stateful devices where this would be problematic must implement SUSPEND. + */ + if (!hdev->suspended && hdev->vhost_ops->vhost_reset_status) { hdev->vhost_ops->vhost_reset_status(hdev); } From patchwork Tue Jul 11 15:52:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309010 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 6679BEB64DC for ; Tue, 11 Jul 2023 15:53:36 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfU-0000eU-6o; Tue, 11 Jul 2023 11:52:48 -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 1qJFfS-0000eG-7V for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:46 -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 1qJFfQ-0001iB-JV for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:52:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090763; 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=eQY1+7pNd7WKWB3DHdDVAKASn6XKPkZ2JsIn2e2HbKY=; b=IikO5Qug3VqSORfuGNELb/iAXVn3iE9bhQ2BzEAqgMC9is0GEPm+jdYGhvpe/a0seSV/eZ KxT9kAcHdDGmT7WuZLTEr69uJrbxgB+RkS41OJUlXckBbzC28KRoYWWlm//7ZqL/decLKP YbjO8sY6v6ZAPEH8O95OCqP3tAiv6LM= 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-613-eBxz59roNvyg0S7wfcptXQ-1; Tue, 11 Jul 2023 11:52:41 -0400 X-MC-Unique: eBxz59roNvyg0S7wfcptXQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E4AB2809F8F for ; Tue, 11 Jul 2023 15:52:40 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8C3C81401C2E; Tue, 11 Jul 2023 15:52:40 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 4/6] vhost-user: Implement suspend/resume Date: Tue, 11 Jul 2023 17:52:26 +0200 Message-ID: <20230711155230.64277-5-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=hreitz@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 Implement SUSPEND/RESUME like vDPA does, by automatically using it in vhost_user_dev_start(). (Though our vDPA code does not implement RESUME yet, so there, the device is reset when it is to be resumed.) Signed-off-by: Hanna Czenczek Reviewed-by: Stefan Hajnoczi --- hw/virtio/vhost-user.c | 99 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 97 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 8dcf049d42..4507de5a92 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -74,6 +74,8 @@ enum VhostUserProtocolFeature { /* Feature 14 reserved for VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS. */ VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15, VHOST_USER_PROTOCOL_F_STATUS = 16, + /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */ + VHOST_USER_PROTOCOL_F_SUSPEND = 18, VHOST_USER_PROTOCOL_F_MAX }; @@ -121,6 +123,8 @@ typedef enum VhostUserRequest { VHOST_USER_REM_MEM_REG = 38, VHOST_USER_SET_STATUS = 39, VHOST_USER_GET_STATUS = 40, + VHOST_USER_SUSPEND = 41, + VHOST_USER_RESUME = 42, VHOST_USER_MAX } VhostUserRequest; @@ -1389,7 +1393,19 @@ static int vhost_user_set_u64(struct vhost_dev *dev, int request, uint64_t u64, static int vhost_user_set_status(struct vhost_dev *dev, uint8_t status) { - return vhost_user_set_u64(dev, VHOST_USER_SET_STATUS, status, false); + int ret; + + ret = vhost_user_set_u64(dev, VHOST_USER_SET_STATUS, status, false); + if (ret < 0) { + return ret; + } + + if (!status) { + /* reset */ + dev->suspended = false; + } + + return 0; } static int vhost_user_get_status(struct vhost_dev *dev, uint8_t *status) @@ -1490,6 +1506,7 @@ static int vhost_user_get_max_memslots(struct vhost_dev *dev, static int vhost_user_reset_device(struct vhost_dev *dev) { + int ret; VhostUserMsg msg = { .hdr.flags = VHOST_USER_VERSION, }; @@ -1499,7 +1516,13 @@ static int vhost_user_reset_device(struct vhost_dev *dev) ? VHOST_USER_RESET_DEVICE : VHOST_USER_RESET_OWNER; - return vhost_user_write(dev, &msg, NULL, 0); + ret = vhost_user_write(dev, &msg, NULL, 0); + if (ret < 0) { + return ret; + } + + dev->suspended = false; + return 0; } static int vhost_user_backend_handle_config_change(struct vhost_dev *dev) @@ -2707,8 +2730,80 @@ void vhost_user_async_close(DeviceState *d, } } +static bool vhost_user_supports_suspend(struct vhost_dev *dev) +{ + return virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_SUSPEND); +} + +static int vhost_user_do_suspend_resume(struct vhost_dev *dev, bool suspend) +{ + VhostUserMsg msg; + bool reply_supported = virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_REPLY_ACK); + VhostUserRequest request = suspend ? VHOST_USER_SUSPEND : VHOST_USER_RESUME; + int ret; + + if (dev->suspended == suspend) { + /* Nothing to do */ + return 0; + } + + if (!vhost_user_supports_suspend(dev)) { + return -ENOTSUP; + } + + msg = (VhostUserMsg) { + .hdr = { + .request = request, + .size = 0, + .flags = VHOST_USER_VERSION, + }, + }; + if (reply_supported) { + msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; + } + + ret = vhost_user_write(dev, &msg, NULL, 0); + if (ret < 0) { + return ret; + } + + if (reply_supported) { + ret = process_message_reply(dev, &msg); + if (ret < 0) { + return ret; + } + } + + dev->suspended = suspend; + return 0; +} + +static int vhost_user_suspend(struct vhost_dev *dev) +{ + return vhost_user_do_suspend_resume(dev, true); +} + +static int vhost_user_resume(struct vhost_dev *dev) +{ + return vhost_user_do_suspend_resume(dev, false); +} + static int vhost_user_dev_start(struct vhost_dev *dev, bool started) { + /* + * Ignore results. If the central vhost code cares, it will check + * dev->suspended. (These calls will fail if the back-end does not + * support suspend/resume, which callers that just want to start the + * device do not care about.) + */ + if (started) { + vhost_user_resume(dev); + } else { + vhost_user_suspend(dev); + } + if (!virtio_has_feature(dev->protocol_features, VHOST_USER_PROTOCOL_F_STATUS)) { return 0; From patchwork Tue Jul 11 15:52:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309012 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 B3B5BC001DD for ; Tue, 11 Jul 2023 15:54:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfj-0000h5-BZ; Tue, 11 Jul 2023 11:53:03 -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 1qJFfh-0000gO-LS for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:53:01 -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 1qJFfg-0001jm-21 for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:53:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090778; 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=GeXzhglug7/8XQU7aDNDJiWbUUC2zz5wdaGpy7Xt+AY=; b=ZRzch7bOE/LY9yTB8Khbo5oZgc0wpw0j+kJFDsMVRe5K2+zqMnE8qv9HCfIqIalbFuYGK2 V1KDvRbYirk7Ha5oaC3tdzWYETSiKOCcoHVw26BZMW/YaWG+aihHD8bbNV2m+iYYWPg3Gy +LKQpBIBY+A+0A5Zr4FEiFdJlx2rxGk= 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-653-Bu-FCH0bMYmVPuW2KLTqyg-1; Tue, 11 Jul 2023 11:52:57 -0400 X-MC-Unique: Bu-FCH0bMYmVPuW2KLTqyg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E5BB51043AC5 for ; Tue, 11 Jul 2023 15:52:56 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B8727F66B9; Tue, 11 Jul 2023 15:37:26 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 5/6] vhost-vdpa: Match vhost-user's status reset Date: Tue, 11 Jul 2023 17:52:27 +0200 Message-ID: <20230711155230.64277-6-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=hreitz@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 vhost-vdpa and vhost-user differ in how they reset the status in their respective vhost_reset_status implementations: vhost-vdpa zeroes it, then re-adds the S_ACKNOWLEDGE and S_DRIVER config bits. S_DRIVER_OK is then set in vhost_vdpa_dev_start(). vhost-user in contrast just zeroes the status, and does no re-add any config bits until vhost_user_dev_start() (where it does re-add all of S_ACKNOWLEDGE, S_DRIVER, and S_DRIVER_OK). There is no documentation for vhost_reset_status, but its only caller is vhost_dev_stop(). So apparently, the device is to be stopped after vhost_reset_status, and therefore it makes more sense to keep the status field fully cleared until the back-end is re-started, which is how vhost-user does it. Make vhost-vdpa do the same -- if nothing else it's confusing to have both vhost implementations handle this differently. Signed-off-by: Hanna Czenczek --- hw/virtio/vhost-vdpa.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index f7fd19a203..0cde8b40de 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -1294,8 +1294,6 @@ static void vhost_vdpa_reset_status(struct vhost_dev *dev) } vhost_vdpa_reset_device(dev); - vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE | - VIRTIO_CONFIG_S_DRIVER); memory_listener_unregister(&v->listener); } @@ -1334,7 +1332,9 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started) } memory_listener_register(&v->listener, dev->vdev->dma_as); - return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); + return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE | + VIRTIO_CONFIG_S_DRIVER | + VIRTIO_CONFIG_S_DRIVER_OK); } return 0; From patchwork Tue Jul 11 15:52:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13309009 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 1635AEB64DC for ; Tue, 11 Jul 2023 15:53:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qJFfm-0000kn-T4; Tue, 11 Jul 2023 11:53:07 -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 1qJFfl-0000ix-Hh for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:53:05 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qJFfk-0001kF-4N for qemu-devel@nongnu.org; Tue, 11 Jul 2023 11:53:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689090783; 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=yFCSSgRaAIPZO+XMfGJU2kcNt0glc0z3zOUfu/gEpeI=; b=gnT5jkM0hRfM+SSgShCIdSQMoXTghEgqZM3YyPUPii2j4FdSCZPwxP+UGwhtXVp3mIyaB2 HwKdCFxsjJ/SznXbFn7CWUl1PXTWxM5l4SDiF+gIPm+O6HX6HCPrj2hGUZnravrvxuNGie dk+tb2m2WjCRuq3P+p3UCF1I0nb1+CU= 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-562-YBBEmGLCO3-KZJxRMbuXcA-1; Tue, 11 Jul 2023 11:52:59 -0400 X-MC-Unique: YBBEmGLCO3-KZJxRMbuXcA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BF5658FBA20 for ; Tue, 11 Jul 2023 15:52:58 +0000 (UTC) Received: from localhost (unknown [10.39.192.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8534640C6CD1; Tue, 11 Jul 2023 13:27:44 +0000 (UTC) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?q?Eugenio_P=C3=A9rez?= , German Maglione Subject: [PATCH 6/6] vhost-user: Have reset_status fall back to reset Date: Tue, 11 Jul 2023 17:52:28 +0200 Message-ID: <20230711155230.64277-7-hreitz@redhat.com> In-Reply-To: <20230711155230.64277-1-hreitz@redhat.com> References: <20230711155230.64277-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@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 The only user of vhost_user_reset_status() is vhost_dev_stop(), which only uses it as a fall-back to stop the back-end if it does not support SUSPEND. However, vhost-user's implementation is a no-op unless the back-end supports SET_STATUS. vhost-vdpa's implementation instead just calls vhost_vdpa_reset_device(), implying that it's OK to fully reset the device if SET_STATUS is not supported. To be fair, vhost_vdpa_reset_device() does nothing but to set the status to zero. However, that may well be because vhost-vdpa has no method besides this to reset a device. In contrast, vhost-user has RESET_DEVICE and a RESET_OWNER, which can be used instead. While it is not entirely clear from documentation or git logs, from discussions and the order of vhost-user protocol features, it appears to me as if RESET_OWNER originally had no real meaning for vhost-user, and was thus used to signal a device reset to the back-end. Then, RESET_DEVICE was introduced, to have a well-defined dedicated reset command. Finally, vhost-user received full STATUS support, including SET_STATUS, so setting the device status to 0 is now the preferred way of resetting a device. Still, RESET_DEVICE and RESET_OWNER should remain valid as fall-backs. Therefore, have vhost_user_reset_status() fall back to vhost_user_reset_device() if the back-end has no STATUS support. Signed-off-by: Hanna Czenczek --- hw/virtio/vhost-user.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 4507de5a92..53a881ec2a 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -2833,6 +2833,8 @@ static void vhost_user_reset_status(struct vhost_dev *dev) if (virtio_has_feature(dev->protocol_features, VHOST_USER_PROTOCOL_F_STATUS)) { vhost_user_set_status(dev, 0); + } else { + vhost_user_reset_device(dev); } }