From patchwork Fri Nov 12 17:07:13 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ryan Harper X-Patchwork-Id: 70991 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 8ADCAB713E for ; Sat, 13 Nov 2010 04:25:24 +1100 (EST) Received: from localhost ([127.0.0.1]:54664 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PGxMy-0000VY-0b for incoming@patchwork.ozlabs.org; Fri, 12 Nov 2010 12:25:00 -0500 Received: from [140.186.70.92] (port=55812 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PGxJF-0006JP-NP for qemu-devel@nongnu.org; Fri, 12 Nov 2010 12:21:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PGx67-0005Kh-VD for qemu-devel@nongnu.org; Fri, 12 Nov 2010 12:07:41 -0500 Received: from e37.co.us.ibm.com ([32.97.110.158]:53506) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PGx67-0005KY-HJ for qemu-devel@nongnu.org; Fri, 12 Nov 2010 12:07:35 -0500 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e37.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id oACH575q021936 for ; Fri, 12 Nov 2010 10:05:07 -0700 Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oACH7KDs144504 for ; Fri, 12 Nov 2010 10:07:20 -0700 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oACHBNTb016427 for ; Fri, 12 Nov 2010 10:11:23 -0700 Received: from localhost.localdomain (sig-9-48-53-248.mts.ibm.com [9.48.53.248]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id oACHBJWK016265; Fri, 12 Nov 2010 10:11:22 -0700 From: Ryan Harper To: Date: Fri, 12 Nov 2010 11:07:13 -0600 Message-Id: <1289581634-21177-2-git-send-email-ryanh@us.ibm.com> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1289581634-21177-1-git-send-email-ryanh@us.ibm.com> References: <1289581634-21177-1-git-send-email-ryanh@us.ibm.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) Cc: Kevin Wolf , "Michael S. Tsirkin" , Markus Armbruster , Anthony Liguori , Ryan Harper , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH 1/2] Implement drive_del to decouple block removal from device removal X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Currently device hotplug removal code is tied to device removal via ACPI. All pci devices that are removable via device_del() require the guest to respond to the request. In some cases the guest may not respond leaving the device still accessible to the guest. The management layer doesn't currently have a reliable way to revoke access to host resource in the presence of an uncooperative guest. This patch implements a new monitor command, drive_del, which provides an explicit command to revoke access to a host block device. drive_del first quiesces the block device (qemu_aio_flush; bdrv_flush() and bdrv_close()). This prevents further IO from being submitted against the host device. Finally, drive_del cleans up pointers between the drive object (host resource) and the device object (guest resource). Signed-off-by: Ryan Harper --- blockdev.c | 39 +++++++++++++++++++++++++++++++++++++++ blockdev.h | 1 + hmp-commands.hx | 18 ++++++++++++++++++ 3 files changed, 58 insertions(+), 0 deletions(-) diff --git a/blockdev.c b/blockdev.c index 6cb179a..f6ac439 100644 --- a/blockdev.c +++ b/blockdev.c @@ -14,6 +14,8 @@ #include "qemu-option.h" #include "qemu-config.h" #include "sysemu.h" +#include "hw/qdev.h" +#include "block_int.h" static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives); @@ -597,3 +599,40 @@ int do_change_block(Monitor *mon, const char *device, } return monitor_read_bdrv_key_start(mon, bs, NULL, NULL); } + +int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data) +{ + const char *id = qdict_get_str(qdict, "id"); + BlockDriverState *bs; + BlockDriverState **ptr; + Property *prop; + + bs = bdrv_find(id); + if (!bs) { + qerror_report(QERR_DEVICE_NOT_FOUND, id); + return -1; + } + + /* quiesce block driver; prevent further io */ + qemu_aio_flush(); + bdrv_flush(bs); + bdrv_close(bs); + + /* clean up guest state from pointing to host resource by + * finding and removing DeviceState "drive" property */ + for (prop = bs->peer->info->props; prop && prop->name; prop++) { + if (prop->info->type == PROP_TYPE_DRIVE) { + ptr = qdev_get_prop_ptr(bs->peer, prop); + if ((*ptr) == bs) { + bdrv_detach(bs, bs->peer); + *ptr = NULL; + break; + } + } + } + + /* clean up host side */ + drive_uninit(drive_get_by_blockdev(bs)); + + return 0; +} diff --git a/blockdev.h b/blockdev.h index 653affc..2a0559e 100644 --- a/blockdev.h +++ b/blockdev.h @@ -51,5 +51,6 @@ int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data); int do_block_set_passwd(Monitor *mon, const QDict *qdict, QObject **ret_data); int do_change_block(Monitor *mon, const char *device, const char *filename, const char *fmt); +int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data); #endif diff --git a/hmp-commands.hx b/hmp-commands.hx index e5585ba..c8b0206 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -68,6 +68,24 @@ Eject a removable medium (use -f to force it). ETEXI { + .name = "drive_del", + .args_type = "id:s", + .params = "device", + .help = "remove host block device", + .user_print = monitor_user_noop, + .mhandler.cmd_new = do_drive_del, + }, + +STEXI +@item drive_del @var{device} +@findex drive_del +Remove host block device. The result is that guest generated IO is no longer +submitted against the host device underlying the disk. Once a drive has +been deleted, the QEMU Block layer returns -EIO which results in IO +errors in the guest for applications that are reading/writing to the device. +ETEXI + + { .name = "change", .args_type = "device:B,target:F,arg:s?", .params = "device filename [format]",