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

@ -1847,10 +1847,16 @@ static void fdctrl_result_timer(void *opaque)
static void fdctrl_connect_drives(FDCtrl *fdctrl)
{
unsigned int i;
FDrive *drive;
for (i = 0; i < MAX_FD; i++) {
fd_init(&fdctrl->drives[i]);
fd_revalidate(&fdctrl->drives[i]);
drive = &fdctrl->drives[i];
fd_init(drive);
fd_revalidate(drive);
if (drive->bs) {
bdrv_set_removable(drive->bs, 1);
}
}
}