Re: [Qemu-devel] [PATCH 03/10] S390: Check Bootdevice Type

[Anthony Liguori]

Alexander Graf <address@hidden> writes:

> On 26.04.2013, at 18:11, Christian Borntraeger wrote:
>
>> On 26/04/13 18:05, Alexander Graf wrote:
>>> 
>>> On 26.04.2013, at 18:01, Christian Borntraeger wrote:
>>> 
>>>> On 26/04/13 17:48, Alexander Graf wrote:
>>>> 
>>>>>> So I suggest to go with this patch and implement later on what we
>>>>>> agree upon?
>>>>> 
>>>>> I don't see how having "first device we find" is any better than a 
>>>>> rushed interface we need to agree on right before 1.5 hard freeze. 
>>>> 
>>>> Exactly, find first device isnt better ;-)
>>>> See, the current code chooses the first subchannel that matches. This
>>>> boils down to "a random disk" as soon as you have more than one.
>>>> 
>>>> With this patch the user can at least specify the devno of the disk.It
>>>> even works out of the box with libvirt.
>>>> 
>>>> Let's just release 1.5 with the very simple one and then go for something 
>>>> awesome in the next version.
>>>> 
>>>> Exactly - and having a list is more in the awesome area. Beiing able to
>>>> specify the first disk and pass that in a register to the bios is of
>>>> course not a full-features interface, but it works and can be changed.
>>> 
>>> My main concern is backwards compatibility. If we introduce a command line 
>>> interface now, we have to support it forever. I'd rather only support one 
>>> interface, rather than 2 out of which one is only legacy for 1.5 
>>> compatibility.
>> 
>> The cool thing is, that we dont introduce a command line interface in this 
>> patch.
>> We just use the existing bootindex. 
>
> Get an ack from Anthony on the bootindex thing and I'm fine with
> pulling that in.

So I don't see a problem with the no-fallback behavior (nor with it
changing down the road), but the bootindex change would cause a
regression on x86.

Regards,

Anthony Liguori

>
>
> Alex