From patchwork Tue Mar 11 16:00:14 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 14012256 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 264A4C282EC for ; Tue, 11 Mar 2025 16:10:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ts2AC-0003lX-Rw; Tue, 11 Mar 2025 12:09:05 -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 1ts22b-0004Pf-PI for qemu-devel@nongnu.org; Tue, 11 Mar 2025 12:01:28 -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 1ts22S-0005mS-2a for qemu-devel@nongnu.org; Tue, 11 Mar 2025 12:01:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741708861; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1SvDv+oKK8AEvt8aEvHnDL9caSTSbyYy2fmRvxxoh7g=; b=OSpElQdQWg5m6HWUUYxirQu2gz/nVbOjwzMMNlwbAzrFU/h+rK7TKzIzC5p1PpLEQ6k8jp 3s/9A+XK4/0SVK412FTtRdbBAGdR8F8uXeChtrNneimkBbwBaKH41JES+YEQedlYfBi7gN P/Eyaomk1ncpJPxPLKOF6MhqS1eZFkE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-530-XX45UFF2Ouyl_ajfe8s6WA-1; Tue, 11 Mar 2025 12:00:58 -0400 X-MC-Unique: XX45UFF2Ouyl_ajfe8s6WA-1 X-Mimecast-MFC-AGG-ID: XX45UFF2Ouyl_ajfe8s6WA_1741708857 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1FB14180AF5E; Tue, 11 Mar 2025 16:00:57 +0000 (UTC) Received: from merkur.redhat.com (unknown [10.44.33.18]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 920FA180AF7C; Tue, 11 Mar 2025 16:00:55 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org Subject: [PULL 15/22] virtio-scsi: protect events_dropped field Date: Tue, 11 Mar 2025 17:00:14 +0100 Message-ID: <20250311160021.349761-16-kwolf@redhat.com> In-Reply-To: <20250311160021.349761-1-kwolf@redhat.com> References: <20250311160021.349761-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@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, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Stefan Hajnoczi The block layer can invoke the resize callback from any AioContext that is processing requests. The virtqueue is already protected but the events_dropped field also needs to be protected against races. Cover it using the event virtqueue lock because it is closely associated with accesses to the virtqueue. Signed-off-by: Stefan Hajnoczi Reviewed-by: Kevin Wolf Message-ID: <20250311132616.1049687-7-stefanha@redhat.com> Signed-off-by: Kevin Wolf --- include/hw/virtio/virtio-scsi.h | 3 ++- hw/scsi/virtio-scsi.c | 29 ++++++++++++++++++++--------- 2 files changed, 22 insertions(+), 10 deletions(-) diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h index 4ee98ebf63..7b7e3ced7a 100644 --- a/include/hw/virtio/virtio-scsi.h +++ b/include/hw/virtio/virtio-scsi.h @@ -82,10 +82,11 @@ struct VirtIOSCSI { SCSIBus bus; int resetting; /* written from main loop thread, read from any thread */ + + QemuMutex event_lock; /* protects event_vq and events_dropped */ bool events_dropped; QemuMutex ctrl_lock; /* protects ctrl_vq */ - QemuMutex event_lock; /* protects event_vq */ /* * TMFs deferred to main loop BH. These fields are protected by diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index 073ccd3d5b..2d796a861b 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -948,7 +948,10 @@ static void virtio_scsi_reset(VirtIODevice *vdev) vs->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE; vs->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE; - s->events_dropped = false; + + WITH_QEMU_LOCK_GUARD(&s->event_lock) { + s->events_dropped = false; + } } typedef struct { @@ -978,14 +981,16 @@ static void virtio_scsi_push_event(VirtIOSCSI *s, } req = virtio_scsi_pop_req(s, vs->event_vq, &s->event_lock); - if (!req) { - s->events_dropped = true; - return; - } + WITH_QEMU_LOCK_GUARD(&s->event_lock) { + if (!req) { + s->events_dropped = true; + return; + } - if (s->events_dropped) { - event |= VIRTIO_SCSI_T_EVENTS_MISSED; - s->events_dropped = false; + if (s->events_dropped) { + event |= VIRTIO_SCSI_T_EVENTS_MISSED; + s->events_dropped = false; + } } if (virtio_scsi_parse_req(req, 0, sizeof(VirtIOSCSIEvent))) { @@ -1014,7 +1019,13 @@ static void virtio_scsi_push_event(VirtIOSCSI *s, static void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq) { - if (s->events_dropped) { + bool events_dropped; + + WITH_QEMU_LOCK_GUARD(&s->event_lock) { + events_dropped = s->events_dropped; + } + + if (events_dropped) { VirtIOSCSIEventInfo info = { .event = VIRTIO_SCSI_T_NO_EVENT, };