Re: [Qemu-devel] [PATCH 0/4] blockdev: Fix 'change' for slot devices

[Peter Maydell]

On 12 January 2016 at 15:47, Max Reitz <address@hidden> wrote:
> The series "BlockBackend and media" intended all block devices with
> removable media to implement a tray model; if the devices does not have
> a tray, it should emulate one.

I tried this for the zaurus (spitz) board, and although "change sd0 file"
now doesn't give an error, it doesn't cause the guest to notice that
an SD card has been inserted either.

I start the guest with no SD card plugged in, and then from the
monitor issue "change sd0 file.img". The sd_cardchange callback
is called (from blk_dev_change_media_cb, with load==true), but
when it sd_cardchange() calls blk_is_inserted(sd->blk) this returns false
and so the SD card model reports to the controller that no card is present.

If I issue the command again, the callback is called twice,
firstly with load=false -- this time blk_is_inserted() returns
true and so the sd card says "card has been inserted" (and the
guest notices this and prints its usual found-mmc-card logging). Then
on the second callback with load==true blk_is_inserted() returns
false again and so the card says "card not inserted".

So it looks like the sense of blk_is_inserted() when the
loading/unloading callbacks are made is the opposite of what the
sd.c code is expecting.

(You can see this behaviour with just the first 2 cc-stable patches.)

thanks
-- PMM