From patchwork Mon Aug 31 09:27:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dima Stepanov X-Patchwork-Id: 275137 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3559C433E2 for ; Mon, 31 Aug 2020 09:28:54 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9B2DE208DB for ; Mon, 31 Aug 2020 09:28:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="TnEo8cwD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B2DE208DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yandex-team.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48182 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kCg7R-00039n-Qh for qemu-devel@archiver.kernel.org; Mon, 31 Aug 2020 05:28:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55636) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kCg6Z-0001Ue-7P; Mon, 31 Aug 2020 05:27:59 -0400 Received: from forwardcorp1p.mail.yandex.net ([2a02:6b8:0:1472:2741:0:8b6:217]:59602) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kCg6W-0004zG-Pm; Mon, 31 Aug 2020 05:27:58 -0400 Received: from sas1-ec30c78b6c5b.qloud-c.yandex.net (sas1-ec30c78b6c5b.qloud-c.yandex.net [IPv6:2a02:6b8:c14:2704:0:640:ec30:c78b]) by forwardcorp1p.mail.yandex.net (Yandex) with ESMTP id 38D132E1590; Mon, 31 Aug 2020 12:27:51 +0300 (MSK) Received: from sas1-58a37b48fb94.qloud-c.yandex.net (sas1-58a37b48fb94.qloud-c.yandex.net [2a02:6b8:c08:1d1b:0:640:58a3:7b48]) by sas1-ec30c78b6c5b.qloud-c.yandex.net (mxbackcorp/Yandex) with ESMTP id nDlPDWXa4i-Rov4wBGi; Mon, 31 Aug 2020 12:27:51 +0300 Precedence: bulk DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1598866071; bh=mkJN5lUBUWPh+shtqKT1+IzCrqgHMkCefejVB9m0YBA=; h=In-Reply-To:In-Reply-To:Message-Id:References:References:Date: Subject:To:From:Cc; b=TnEo8cwDgGNwkKLurN6wngR3xc/Ib5aCmlwgSrBy7fe6enLQhEnt7s+tdonW+lRTj oqUW/IMLYjzSFiSQwCh/bZ8GJdl0G+p0VDbPe+tSxrtP+hrjJ0sxarrKebBL4RgJT5 rQ8kxVKssNN/5H8QcuqxE5pOzc3/f8EQuR0JETck= Authentication-Results: sas1-ec30c78b6c5b.qloud-c.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-vpn.dhcp.yndx.net (dynamic-vpn.dhcp.yndx.net [2a02:6b8:b081:216::1:a]) by sas1-58a37b48fb94.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id yaozkQMlmT-Rom8h0Zl; Mon, 31 Aug 2020 12:27:50 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (Client certificate not present) From: Dima Stepanov To: qemu-devel@nongnu.org Subject: [PATCH v3 1/7] vhost: recheck dev state in the vhost_migration_log routine Date: Mon, 31 Aug 2020 12:27:17 +0300 Message-Id: X-Mailer: git-send-email 2.7.4 In-Reply-To: References: In-Reply-To: References: Received-SPF: pass client-ip=2a02:6b8:0:1472:2741:0:8b6:217; envelope-from=dimastep@yandex-team.ru; helo=forwardcorp1p.mail.yandex.net X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/31 04:24:12 X-ACL-Warn: Detected OS = ??? 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, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, lvivier@redhat.com, thuth@redhat.com, qemu-block@nongnu.org, mst@redhat.com, jasowang@redhat.com, dgilbert@redhat.com, mreitz@redhat.com, fengli@smartx.com, yc-core@yandex-team.ru, pbonzini@redhat.com, raphael.norwitz@nutanix.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" vhost-user devices can get a disconnect in the middle of the VHOST-USER handshake on the migration start. If disconnect event happened right before sending next VHOST-USER command, then the vhost_dev_set_log() call in the vhost_migration_log() function will return error. This error will lead to the assert() and close the QEMU migration source process. For the vhost-user devices the disconnect event should not break the migration process, because: - the device will be in the stopped state, so it will not be changed during migration - if reconnect will be made the migration log will be reinitialized as part of reconnect/init process: #0 vhost_log_global_start (listener=0x563989cf7be0) at hw/virtio/vhost.c:920 #1 0x000056398603d8bc in listener_add_address_space (listener=0x563989cf7be0, as=0x563986ea4340 ) at softmmu/memory.c:2664 #2 0x000056398603dd30 in memory_listener_register (listener=0x563989cf7be0, as=0x563986ea4340 ) at softmmu/memory.c:2740 #3 0x0000563985fd6956 in vhost_dev_init (hdev=0x563989cf7bd8, opaque=0x563989cf7e30, backend_type=VHOST_BACKEND_TYPE_USER, busyloop_timeout=0) at hw/virtio/vhost.c:1385 #4 0x0000563985f7d0b8 in vhost_user_blk_connect (dev=0x563989cf7990) at hw/block/vhost-user-blk.c:315 #5 0x0000563985f7d3f6 in vhost_user_blk_event (opaque=0x563989cf7990, event=CHR_EVENT_OPENED) at hw/block/vhost-user-blk.c:379 Update the vhost-user-blk device with the internal started_vu field which will be used for initialization (vhost_user_blk_start) and clean up (vhost_user_blk_stop). This additional flag in the VhostUserBlk structure will be used to track whether the device really needs to be stopped and cleaned up on a vhost-user level. The disconnect event will set the overall VHOST device (not vhost-user) to the stopped state, so it can be used by the general vhost_migration_log routine. Such approach could be propogated to the other vhost-user devices, but better idea is just to make the same connect/disconnect code for all the vhost-user devices. This migration issue was slightly discussed earlier: - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg01509.html - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg05241.html Signed-off-by: Dima Stepanov Reviewed-by: Raphael Norwitz --- hw/block/vhost-user-blk.c | 19 ++++++++++++++++--- hw/virtio/vhost.c | 27 ++++++++++++++++++++++++--- include/hw/virtio/vhost-user-blk.h | 10 ++++++++++ 3 files changed, 50 insertions(+), 6 deletions(-) diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index 39aec42..a076b1e 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -150,6 +150,7 @@ static int vhost_user_blk_start(VirtIODevice *vdev) error_report("Error starting vhost: %d", -ret); goto err_guest_notifiers; } + s->started_vu = true; /* guest_notifier_mask/pending not used yet, so just unmask * everything here. virtio-pci will do the right thing by @@ -175,6 +176,11 @@ static void vhost_user_blk_stop(VirtIODevice *vdev) VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); int ret; + if (!s->started_vu) { + return; + } + s->started_vu = false; + if (!k->set_guest_notifiers) { return; } @@ -341,9 +347,7 @@ static void vhost_user_blk_disconnect(DeviceState *dev) } s->connected = false; - if (s->dev.started) { - vhost_user_blk_stop(vdev); - } + vhost_user_blk_stop(vdev); vhost_dev_cleanup(&s->dev); } @@ -399,6 +403,15 @@ static void vhost_user_blk_event(void *opaque, QEMUChrEvent event) 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). + */ + s->dev.started = false; break; case CHR_EVENT_BREAK: case CHR_EVENT_MUX_IN: diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 1a1384e..ffef7ab 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -861,21 +861,42 @@ static int vhost_migration_log(MemoryListener *listener, bool enable) dev->log_enabled = enable; return 0; } + + r = 0; if (!enable) { r = vhost_dev_set_log(dev, false); if (r < 0) { - return r; + goto check_dev_state; } vhost_log_put(dev, false); } else { vhost_dev_log_resize(dev, vhost_get_log_size(dev)); r = vhost_dev_set_log(dev, true); if (r < 0) { - return r; + goto check_dev_state; } } + +check_dev_state: dev->log_enabled = enable; - return 0; + /* + * vhost-user-* devices could change their state during log + * initialization due to disconnect. So check dev state after + * vhost communication. + */ + if (!dev->started) { + /* + * Since device is in the stopped state, it is okay for + * migration. Return success. + */ + r = 0; + } + if (r) { + /* An error is occured. */ + dev->log_enabled = false; + } + + return r; } static void vhost_log_global_start(MemoryListener *listener) diff --git a/include/hw/virtio/vhost-user-blk.h b/include/hw/virtio/vhost-user-blk.h index 292d171..4d6f4c0 100644 --- a/include/hw/virtio/vhost-user-blk.h +++ b/include/hw/virtio/vhost-user-blk.h @@ -40,7 +40,17 @@ typedef struct VHostUserBlk { VhostUserState vhost_user; struct vhost_virtqueue *vhost_vqs; VirtQueue **virtqs; + + /* + * There are at least two steps of initialization of the + * vhost-user device. The first is a "connect" step and + * second is a "start" step. Make a separation between + * those initialization phases by using two fields. + */ + /* vhost_user_blk_connect/vhost_user_blk_disconnect */ bool connected; + /* vhost_user_blk_start/vhost_user_blk_stop */ + bool started_vu; } VHostUserBlk; #endif