Re: [Qemu-devel] [PULL v2 10/40] blockdev: Implement change with basic operations

[Peter Maydell]

On 10 November 2015 at 14:09, Kevin Wolf <address@hidden> wrote:
> From: Max Reitz <address@hidden>
>
> Implement 'change' on block devices by calling blockdev-open-tray,
> blockdev-remove-medium, blockdev-insert-medium (a variation of that
> which does not need a node-name) and blockdev-close-tray.
>
> Signed-off-by: Max Reitz <address@hidden>
> Signed-off-by: Kevin Wolf <address@hidden>

I think this commit broke the monitor 'change' command for
sd card devices. In 2.4, for a Zaurus ('spitz') machine:
change sd0 /home/petmay01/test-images/RaspberryPi/pifi-4g.img

causes the guest to print
mmc0: new SDHC card at address 4567
mmcblk0: mmc0:4567 QEMU! 4.00 GiB
 mmcblk0: p1 p2 p3 p4

ie it detects we have just provided a new SD card.

In 2.5 trying this gives an error in the monitor:
Tray of device 'sd0' is not open

This seems to be because with this commit we now try to do
a qmp_blockdev_open_tray() on the device. This fails for SD cards
(which don't have any kind of tray in real life), because we
don't implement the is_tray_open hook and so get the default
"tray always closed" behaviour. But in the old code you could
perfectly well change the backing medium even on a device
without a tray...

Was this breakage intentional?

thanks
-- PMM