From patchwork Thu Apr 20 11:37:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13218569 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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 281C6C77B73 for ; Thu, 20 Apr 2023 11:38:05 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.524122.814767 (Exim 4.92) (envelope-from ) id 1ppSbn-0001Op-2Q; Thu, 20 Apr 2023 11:37:51 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 524122.814767; Thu, 20 Apr 2023 11:37:51 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ppSbm-0001Oi-VR; Thu, 20 Apr 2023 11:37:50 +0000 Received: by outflank-mailman (input) for mailman id 524122; Thu, 20 Apr 2023 11:37:49 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ppSbl-00017u-1y for xen-devel@lists.xenproject.org; Thu, 20 Apr 2023 11:37:49 +0000 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id c619e470-df6f-11ed-b21f-6b7b168915f2; Thu, 20 Apr 2023 13:37:48 +0200 (CEST) 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-587-VCLxhnfSPFqLD1O2cun8pQ-1; Thu, 20 Apr 2023 07:37:42 -0400 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 44168380671E; Thu, 20 Apr 2023 11:37:41 +0000 (UTC) Received: from localhost (unknown [10.39.193.254]) by smtp.corp.redhat.com (Postfix) with ESMTP id 213381410F1C; Thu, 20 Apr 2023 11:37:39 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c619e470-df6f-11ed-b21f-6b7b168915f2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681990667; 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=ct1ICfub90ccCopLja+U3Sq9ZQX/65uvuN+fpfLMIoc=; b=SibGHQhKPwH260n+GV9EZs4FUJwLqfTDL30rrhZFCTcwSTBOLGtZGqgAZSiUpjayUmkVUa OG5EZJmXmeDXx3fluHL0Td9uOw3GVj+OPBoxefJt2QKYdWIpCGtjGrWASqsHD7EIYU1XTg pA/PCNmLM4cw6qidhmKcTFPvIpZ/qnA= X-MC-Unique: VCLxhnfSPFqLD1O2cun8pQ-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Peter Lieven , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Paolo Bonzini , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Xie Yongji , Juan Quintela , qemu-block@nongnu.org, Eduardo Habkost , Richard Henderson , David Woodhouse , Stefan Weil , Fam Zheng , Julia Suvorova , Ronnie Sahlberg , xen-devel@lists.xenproject.org, Hanna Reitz , "Dr. David Alan Gilbert" , eesposit@redhat.com, Kevin Wolf , Marcel Apfelbaum , Stefano Stabellini , Paul Durrant , Aarushi Mehta , "Michael S. Tsirkin" , Anthony Perard , "Richard W.M. Jones" , Coiby Xu , Stefano Garzarella , Daniil Tatianin Subject: [PATCH v3 02/20] virtio-scsi: avoid race between unplug and transport event Date: Thu, 20 Apr 2023 07:37:14 -0400 Message-Id: <20230420113732.336620-3-stefanha@redhat.com> In-Reply-To: <20230420113732.336620-1-stefanha@redhat.com> References: <20230420113732.336620-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Only report a transport reset event to the guest after the SCSIDevice has been unrealized by qdev_simple_device_unplug_cb(). qdev_simple_device_unplug_cb() sets the SCSIDevice's qdev.realized field to false so that scsi_device_find/get() no longer see it. scsi_target_emulate_report_luns() also needs to be updated to filter out SCSIDevices that are unrealized. These changes ensure that the guest driver does not see the SCSIDevice that's being unplugged if it responds very quickly to the transport reset event. Reviewed-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Reviewed-by: Daniil Tatianin Signed-off-by: Stefan Hajnoczi --- hw/scsi/scsi-bus.c | 3 ++- hw/scsi/virtio-scsi.c | 18 +++++++++--------- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 07275fb631..64d7311757 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -486,7 +486,8 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r) DeviceState *qdev = kid->child; SCSIDevice *dev = SCSI_DEVICE(qdev); - if (dev->channel == channel && dev->id == id && dev->lun != 0) { + if (dev->channel == channel && dev->id == id && dev->lun != 0 && + qdev_is_realized(&dev->qdev)) { store_lun(tmp, dev->lun); g_byte_array_append(buf, tmp, 8); len += 8; diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index 612c525d9d..000961446c 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -1063,15 +1063,6 @@ static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev, SCSIDevice *sd = SCSI_DEVICE(dev); AioContext *ctx = s->ctx ?: qemu_get_aio_context(); - if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) { - virtio_scsi_acquire(s); - virtio_scsi_push_event(s, sd, - VIRTIO_SCSI_T_TRANSPORT_RESET, - VIRTIO_SCSI_EVT_RESET_REMOVED); - scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED)); - virtio_scsi_release(s); - } - aio_disable_external(ctx); qdev_simple_device_unplug_cb(hotplug_dev, dev, errp); aio_enable_external(ctx); @@ -1082,6 +1073,15 @@ static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev, blk_set_aio_context(sd->conf.blk, qemu_get_aio_context(), NULL); virtio_scsi_release(s); } + + if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) { + virtio_scsi_acquire(s); + virtio_scsi_push_event(s, sd, + VIRTIO_SCSI_T_TRANSPORT_RESET, + VIRTIO_SCSI_EVT_RESET_REMOVED); + scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED)); + virtio_scsi_release(s); + } } static struct SCSIBusInfo virtio_scsi_scsi_info = {