@@ -1328,6 +1328,13 @@ void bdrv_set_removable(BlockDriverState *bs, int removable)
}
}
+void bdrv_unplug(BlockDriverState *bs)
+{
+ qemu_aio_flush();
+ bdrv_flush(bs);
+ bdrv_close(bs);
+}
+
int bdrv_is_removable(BlockDriverState *bs)
{
return bs->removable;
@@ -171,6 +171,7 @@ void bdrv_set_on_error(BlockDriverState *bs, BlockErrorAction on_read_error,
BlockErrorAction on_write_error);
BlockErrorAction bdrv_get_on_error(BlockDriverState *bs, int is_read);
void bdrv_set_removable(BlockDriverState *bs, int removable);
+void bdrv_unplug(BlockDriverState *bs);
int bdrv_is_removable(BlockDriverState *bs);
int bdrv_is_read_only(BlockDriverState *bs);
int bdrv_is_sg(BlockDriverState *bs);
@@ -597,3 +597,20 @@ int do_change_block(Monitor *mon, const char *device,
}
return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
}
+
+int do_drive_unplug(Monitor *mon, const QDict *qdict, QObject **ret_data)
+{
+ const char *id = qdict_get_str(qdict, "id");
+ BlockDriverState *bs;
+
+ bs = bdrv_find(id);
+ if (!bs) {
+ qerror_report(QERR_DEVICE_NOT_FOUND, id);
+ return -1;
+ }
+
+ bdrv_unplug(bs);
+
+ return 0;
+}
+
@@ -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_unplug(Monitor *mon, const QDict *qdict, QObject **ret_data);
#endif
@@ -68,6 +68,26 @@ Eject a removable medium (use -f to force it).
ETEXI
{
+ .name = "drive_unplug",
+ .args_type = "id:s",
+ .params = "device",
+ .help = "unplug block device",
+ .user_print = monitor_user_noop,
+ .mhandler.cmd_new = do_drive_unplug,
+ },
+
+STEXI
+@item unplug @var{device}
+@findex unplug
+Unplug 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 unplugged, the QEMU Block layer returns -EIO which results in IO
+errors in the guest for applications that are reading/writing to the device
+when it is unplugged. Unplugged block devices can be safely deleted along with
+the associated pci devices (if present).
+ETEXI
+
+ {
.name = "change",
.args_type = "device:B,target:F,arg:s?",
.params = "device filename [format]",
Block hot unplug is racy since the guest is required to acknowlege the ACPI unplug event; this may not happen synchronously with the device removal command This series aims to close a gap where by mgmt applications that assume the block resource has been removed without confirming that the guest has acknowledged the removal may re-assign the underlying device to a second guest leading to data leakage. This series introduces a new montor command to decouple asynchornous device removal from restricting guest access to a block device. We do this by creating a new monitor command drive_unplug which maps to a bdrv_unplug() command which does a qemu_aio_flush; bdrv_flush() and bdrv_close(). Once complete, subsequent IO is rejected from the device and the guest will get IO errors but continue to function. A subsequent device removal command can be issued to remove the device, to which the guest may or maynot respond, but as long as the unplugged bit is set, no IO will be sumbitted. Signed-off-by: Ryan Harper <ryanh@us.ibm.com> --- block.c | 7 +++++++ block.h | 1 + blockdev.c | 17 +++++++++++++++++ blockdev.h | 1 + hmp-commands.hx | 20 ++++++++++++++++++++ 5 files changed, 46 insertions(+), 0 deletions(-)