block: Fix virtual media change for if=none

BlockDriverState member removable controls whether virtual media
change (monitor commands change, eject) is allowed.  It is set when
the "type hint" is BDRV_TYPE_CDROM or BDRV_TYPE_FLOPPY.

The type hint is only set by drive_init().  It sets BDRV_TYPE_FLOPPY
for if=floppy.  It sets BDRV_TYPE_CDROM for media=cdrom and if=ide,
scsi, xen, or none.

if=ide and if=scsi work, because the type hint makes it a CD-ROM.
if=xen likewise, I think.

For the same reason, if=none works when it's used by ide-drive or
scsi-disk.  For other guest devices, there are problems:

* fdc: you can't change virtual media

    $ qemu [...] -drive if=none,id=foo,... -global isa-fdc.driveA=foo
    QEMU 0.12.50 monitor - type 'help' for more information
    (qemu) eject foo
    Device 'foo' is not removable

  unless you add media=cdrom, but that makes it readonly.

* virtio: if you add media=cdrom, you can change virtual media.  If
  you eject, the guest gets I/O errors.  If you change, the guest sees
  the drive's contents suddenly change.

* scsi-generic: if you add media=cdrom, you can change virtual media.
  I didn't test what that does to the guest or the physical device,
  but it can't be pretty.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Markus Armbruster 2010-06-25 13:42:14 +02:00 committed by Kevin Wolf
parent 3ac906f771
commit 7d0d69509a
7 changed files with 24 additions and 3 deletions

View file

@ -1299,6 +1299,14 @@ BlockErrorAction bdrv_get_on_error(BlockDriverState *bs, int is_read)
return is_read ? bs->on_read_error : bs->on_write_error;
}
void bdrv_set_removable(BlockDriverState *bs, int removable)
{
bs->removable = removable;
if (removable && bs == bs_snapshots) {
bs_snapshots = NULL;
}
}
int bdrv_is_removable(BlockDriverState *bs)
{
return bs->removable;