From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=46128 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PGviR-0000hr-7R for qemu-devel@nongnu.org; Fri, 12 Nov 2010 10:39:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PGviP-0000MZ-VB for qemu-devel@nongnu.org; Fri, 12 Nov 2010 10:39:03 -0500 Received: from e9.ny.us.ibm.com ([32.97.182.139]:47997) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PGviP-0000I3-RS for qemu-devel@nongnu.org; Fri, 12 Nov 2010 10:39:01 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e9.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id oACFH3oj003860 for ; Fri, 12 Nov 2010 10:17:03 -0500 Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oACFcUka451392 for ; Fri, 12 Nov 2010 10:38:31 -0500 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oACFcU0W007983 for ; Fri, 12 Nov 2010 08:38:30 -0700 From: Ryan Harper Date: Fri, 12 Nov 2010 09:38:08 -0600 Message-Id: <1289576289-27888-2-git-send-email-ryanh@us.ibm.com> In-Reply-To: <1289576289-27888-1-git-send-email-ryanh@us.ibm.com> References: <1289576289-27888-1-git-send-email-ryanh@us.ibm.com> Subject: [Qemu-devel] [PATCH 1/2] Implement drive_del to decouple block removal from device removal List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , "Michael S. Tsirkin" , Markus Armbruster , Anthony Liguori , Ryan Harper , Stefan Hajnoczi 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..d6dc18c 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 delete @var{device} +@findex delete +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]", -- 1.6.3.3