From patchwork Tue May 16 19:02:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13243526 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 403CCC77B7A for ; Tue, 16 May 2023 19:03:17 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.535457.833198 (Exim 4.92) (envelope-from ) id 1pyzww-0003Kc-NK; Tue, 16 May 2023 19:03:06 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 535457.833198; Tue, 16 May 2023 19:03:06 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pyzww-0003KT-Jo; Tue, 16 May 2023 19:03:06 +0000 Received: by outflank-mailman (input) for mailman id 535457; Tue, 16 May 2023 19:03:05 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pyzwv-0002US-1z for xen-devel@lists.xenproject.org; Tue, 16 May 2023 19:03:05 +0000 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 47f91588-f41c-11ed-8611-37d641c3527e; Tue, 16 May 2023 21:03:03 +0200 (CEST) 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-584-ZScnqIcZMPy3U2EgdpHnTw-1; Tue, 16 May 2023 15:02:56 -0400 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 725C286C614; Tue, 16 May 2023 19:02:55 +0000 (UTC) Received: from localhost (unknown [10.39.192.44]) by smtp.corp.redhat.com (Postfix) with ESMTP id C6A3A492B00; Tue, 16 May 2023 19:02:53 +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: 47f91588-f41c-11ed-8611-37d641c3527e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684263782; 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=U+xP3+VvbKptobyZr1DGqYiArlGHMgmGr4twrwXIfR0=; b=cCtxVferhgqNV03zDDb6ITSy08KyDlcBF96EQWwebrcMuFZ3PQnmkk4bKNHtBcebBPcTJi cMZFwgpzDzF0Qnj1Osyt8F+8f9dc7QJ4RMKvKSoPj0GC5LYQth1i/K9uuyVjVwcYl8UIaJ fPIVMpcVV30H0JoooekDHiHDUg0ivhE= X-MC-Unique: ZScnqIcZMPy3U2EgdpHnTw-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Coiby Xu , Marcel Apfelbaum , "Michael S. Tsirkin" , "Richard W.M. Jones" , Peter Xu , xen-devel@lists.xenproject.org, Kevin Wolf , Ronnie Sahlberg , Stefano Stabellini , Richard Henderson , Stefan Hajnoczi , Julia Suvorova , Hanna Reitz , Leonardo Bras , eesposit@redhat.com, Fam Zheng , Aarushi Mehta , David Woodhouse , Xie Yongji , Stefano Garzarella , qemu-block@nongnu.org, Eduardo Habkost , Paul Durrant , Stefan Weil , Anthony Perard , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Peter Lieven , Paolo Bonzini , =?utf-8?q?P?= =?utf-8?q?hilippe_Mathieu-Daud=C3=A9?= , Juan Quintela , Daniil Tatianin Subject: [PATCH v6 03/20] virtio-scsi: avoid race between unplug and transport event Date: Tue, 16 May 2023 15:02:21 -0400 Message-Id: <20230516190238.8401-4-stefanha@redhat.com> In-Reply-To: <20230516190238.8401-1-stefanha@redhat.com> References: <20230516190238.8401-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 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. Change virtio_scsi_push_event() to take event information as an argument instead of the SCSIDevice. This allows virtio_scsi_hotunplug() to emit a VIRTIO_SCSI_T_TRANSPORT_RESET event after the SCSIDevice has already been 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 Reviewed-by: Kevin Wolf --- v5: - Stash SCSIDevice id/lun values for VIRTIO_SCSI_T_TRANSPORT_RESET event before unrealizing the SCSIDevice [Kevin] --- hw/scsi/scsi-bus.c | 3 +- hw/scsi/virtio-scsi.c | 86 ++++++++++++++++++++++++++++++------------- 2 files changed, 63 insertions(+), 26 deletions(-) diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 8857ff41f6..64013c8a24 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -487,7 +487,8 @@ 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..ae314af3de 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -933,13 +933,27 @@ static void virtio_scsi_reset(VirtIODevice *vdev) s->events_dropped = false; } -static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev, - uint32_t event, uint32_t reason) +typedef struct { + uint32_t event; + uint32_t reason; + union { + /* Used by messages specific to a device */ + struct { + uint32_t id; + uint32_t lun; + } address; + }; +} VirtIOSCSIEventInfo; + +static void virtio_scsi_push_event(VirtIOSCSI *s, + const VirtIOSCSIEventInfo *info) { VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); VirtIOSCSIReq *req; VirtIOSCSIEvent *evt; VirtIODevice *vdev = VIRTIO_DEVICE(s); + uint32_t event = info->event; + uint32_t reason = info->reason; if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) { return; @@ -965,27 +979,28 @@ static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev, memset(evt, 0, sizeof(VirtIOSCSIEvent)); evt->event = virtio_tswap32(vdev, event); evt->reason = virtio_tswap32(vdev, reason); - if (!dev) { - assert(event == VIRTIO_SCSI_T_EVENTS_MISSED); - } else { + if (event != VIRTIO_SCSI_T_EVENTS_MISSED) { evt->lun[0] = 1; - evt->lun[1] = dev->id; + evt->lun[1] = info->address.id; /* Linux wants us to keep the same encoding we use for REPORT LUNS. */ - if (dev->lun >= 256) { - evt->lun[2] = (dev->lun >> 8) | 0x40; + if (info->address.lun >= 256) { + evt->lun[2] = (info->address.lun >> 8) | 0x40; } - evt->lun[3] = dev->lun & 0xFF; + evt->lun[3] = info->address.lun & 0xFF; } trace_virtio_scsi_event(virtio_scsi_get_lun(evt->lun), event, reason); - + virtio_scsi_complete_req(req); } static void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq) { if (s->events_dropped) { - virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0); + VirtIOSCSIEventInfo info = { + .event = VIRTIO_SCSI_T_NO_EVENT, + }; + virtio_scsi_push_event(s, &info); } } @@ -1009,9 +1024,17 @@ static void virtio_scsi_change(SCSIBus *bus, SCSIDevice *dev, SCSISense sense) if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_CHANGE) && dev->type != TYPE_ROM) { + VirtIOSCSIEventInfo info = { + .event = VIRTIO_SCSI_T_PARAM_CHANGE, + .reason = sense.asc | (sense.ascq << 8), + .address = { + .id = dev->id, + .lun = dev->lun, + }, + }; + virtio_scsi_acquire(s); - virtio_scsi_push_event(s, dev, VIRTIO_SCSI_T_PARAM_CHANGE, - sense.asc | (sense.ascq << 8)); + virtio_scsi_push_event(s, &info); virtio_scsi_release(s); } } @@ -1046,10 +1069,17 @@ static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev, } if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) { + VirtIOSCSIEventInfo info = { + .event = VIRTIO_SCSI_T_TRANSPORT_RESET, + .reason = VIRTIO_SCSI_EVT_RESET_RESCAN, + .address = { + .id = sd->id, + .lun = sd->lun, + }, + }; + virtio_scsi_acquire(s); - virtio_scsi_push_event(s, sd, - VIRTIO_SCSI_T_TRANSPORT_RESET, - VIRTIO_SCSI_EVT_RESET_RESCAN); + virtio_scsi_push_event(s, &info); scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED)); virtio_scsi_release(s); } @@ -1062,15 +1092,14 @@ static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev, VirtIOSCSI *s = VIRTIO_SCSI(vdev); 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); - } + VirtIOSCSIEventInfo info = { + .event = VIRTIO_SCSI_T_TRANSPORT_RESET, + .reason = VIRTIO_SCSI_EVT_RESET_REMOVED, + .address = { + .id = sd->id, + .lun = sd->lun, + }, + }; aio_disable_external(ctx); qdev_simple_device_unplug_cb(hotplug_dev, dev, errp); @@ -1082,6 +1111,13 @@ 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, &info); + scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED)); + virtio_scsi_release(s); + } } static struct SCSIBusInfo virtio_scsi_scsi_info = {