Re: [Qemu-devel] [PATCH for-2.3 0/3] Contain drive_get() misuse

[Paolo Bonzini <pbonzini@redhat.com>]

On 24/03/2015 13:48, Markus Armbruster wrote:
> Use of -drive if=floppy with onboard pc87312 (machine "prep") shouldn't
> be affected.  Likewise for connecting onboard m25p80-generic derivatives
> with if=mtd drives, or onboard ssi-sd with if=sd.

Exactly.

> Weird usage similar to the one you caught in time for sdhci-pci (--drive
> if=sd --device sdhci-pci) would break.  It's possible when the target
> has the device, and the machine type has a suitable bus.
> 
> * pc87312
> 
>   Depends on CONFIG_PC87312, set in {ppc,ppc64}-softmmu.mak.
> 
>   Requires an ISA bus.  I believe "prep" is the only machine providing
>   one.

You can add one with -device i82378.  Actually used in
tests/endianness-test.c, hence I guess supported.

>   If Andreas agrees, I can set cannot_instantiate_with_device_add_yet
>   for pc87312 now.

Could do that, could also decide that "-device i82378 -device pc87312"
is a valid way to add all the legacy crap to a PCI machine.  In which
case supporting "-drive if=floppy" is a weird feature but it's also hard
to call it a bug.

The difference with other devices is that you can only add it once.
It's a big difference.

> * ssi-sd
> 
>   I guess we want to document that --device ssi-sd will at some point
>   cease to auto-connect to the next available if=sd drive and require
>   the usual drive property instead.  Okay?
> 
> * m25p80-generic
>  
>   Document just like ssi-sd.

Ack for these two.  Boards can still hook -drive if={sd,mtd} to them,
but (hypothetical) users would have to switch to -drive if=none.

Paolo

> [...]
>> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> Thanks!
>