From patchwork Tue Mar 11 13:07:33 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 14011922 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 7CE44C28B2E for ; Tue, 11 Mar 2025 13:32:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1trzNv-00076G-6S; Tue, 11 Mar 2025 09:11:03 -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 1trzLM-0004NN-Hd for qemu-devel@nongnu.org; Tue, 11 Mar 2025 09:08:25 -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 1trzLK-0001bX-Me for qemu-devel@nongnu.org; Tue, 11 Mar 2025 09:08:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741698501; 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=CE1im9Bjq31X9Eaxj30dsdZEIRgev+UbxVXubrTF5n4=; b=brz/YfqNEgLUT7WDpYr1S8iqB/K3zaSz4Sv6AYdHQ/lHVRjcKhmJ29hiFRZCi/hv5yhqJv UUVWrWENY4hk7GYY/90b9gM0IfBl58OayyrKgp7MYF33gYzF20Vz9F5U+wLxhNgHUaHoUB NFITMA2KPgIg3gwT5YZRoTJvCCGZp/I= 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-169-ESw7CSc-P9uLxqfrbqYHvA-1; Tue, 11 Mar 2025 09:08:18 -0400 X-MC-Unique: ESw7CSc-P9uLxqfrbqYHvA-1 X-Mimecast-MFC-AGG-ID: ESw7CSc-P9uLxqfrbqYHvA_1741698496 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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 5F8961800EC5; Tue, 11 Mar 2025 13:08:16 +0000 (UTC) Received: from localhost (unknown [10.2.16.91]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1E2B31956094; Tue, 11 Mar 2025 13:08:14 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Kevin Wolf , pkrempa@redhat.com, Paolo Bonzini , qemu-block@nongnu.org, =?utf-8?q?Phili?= =?utf-8?q?ppe_Mathieu-Daud=C3=A9?= , Stefan Hajnoczi , David Hildenbrand , "Michael S. Tsirkin" , Hanna Reitz , Peter Xu , Fam Zheng , John Snow Subject: [PATCH v3 06/14] virtio-scsi: protect events_dropped field Date: Tue, 11 Mar 2025 21:07:33 +0800 Message-ID: <20250311130741.1047903-7-stefanha@redhat.com> In-Reply-To: <20250311130741.1047903-1-stefanha@redhat.com> References: <20250311130741.1047903-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@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_H5=0.001, RCVD_IN_MSPIKE_WL=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=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 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 --- 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, };