Re: [Qemu-devel] [PATCH v2] ahci: add -drive support

[Alexander Graf]

On 09.07.2012, at 11:11, Kevin Wolf wrote:

> Am 09.07.2012 10:50, schrieb Markus Armbruster:
>> Alexander Graf <address@hidden> writes:
>> 
>>> We've had support for creating AHCI devices using -device for a while now,
>>> but it's cumbersome to users. We really should provide an easier way for
>>> them to leverage the power of AHCI!
>>> 
>>> So let's introduce a new if= option to -drive, giving users the same
>>> command line experience as for scsi or ide.
>>> 
>>> Signed-off-by: Alexander Graf <address@hidden>
>>> 
>>> ---
>>> 
>>> v1 -> v2:
>>> 
>>>  - support more than a single drive per adapter
>>>  - support index= option
>>>  - treat IF_AHCI the same as IF_IDE
>> 
>> Inhowfar?  Not obvious to me from the patch, or the diff patch v1.
>> 
>>>  - add is_ata() helper to match AHCI || IDE
>> 
>> Not addressed:
>> 
>> Once we switch to q35, if=ahci will become a redundant wart: to add
>> drives to the board's AHCI controller, you'll have to use if=ide.
>> if=ahci will create new controllers, which is generally not what you
>> want.  Ugh.
> 
> Can we even make it the default with q35 as long as our AHCI controller
> doesn't also expose a legacy interface for compatibility?

What legacy interface? The ICH-9 can be controlled by the _BIOS_ to switch 
between 2 PCI IDs. One for IDE mode, one for AHCI mode. I don't think that 
would help us here, would it?


Alex