* Kevin Wolf <kw...@redhat.com> [2010-11-12 10:43]:
> Am 12.11.2010 16:38, schrieb Ryan Harper:
> > 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 <ry...@us.ibm.com>
> > ---
> > 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
>
> I think this should be @item drive_del and @findex drive_del.
Yep.
>
> Kevin
--
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
ry...@us.ibm.com
