Re: [Qemu-devel] [PATCH 01/10] Common: Add a default bootindex for all applicable devices

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 26/04/13 20:01, Dominik Dingel wrote:
> On Fri, 26 Apr 2013 11:36:11 -0500
> Anthony Liguori <anthony@codemonkey.ws> wrote:
> 
>> Dominik Dingel <dingel@linux.vnet.ibm.com> writes:
>>
>>> Currently only devices with a positive boot index will be pushed in the
>>> fw_boot_order queue, so if no boot index at all will be specified,
>>> the queue ends up empty.
>>>
>>> Instead we push exactly as docs/bootindex.txt says the devices with
>>> the lowest possible boot priority at the tail of the queue,
>>> because we give them the highest available boot index.
>>>
>>> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
>>
>> Wouldn't this break the ability to say: "don't every try to boot from
>> this device?"
>>
>> As an example, some people want to force PXE boot to not be tried on
>> certain networks.
>>
>> Regards,
>>
>> Anthony Liguori
> 
> That is correct, hmm. The thing is, if we don't submit a bootindex, we will assign -1 in virtio-blk and virtio-net. This would forbid that the device would be booted from. 
> Where docs/bootindex.txt says: if a device got no bootindex, it gets the lowest possibly priority... 

Hmm, reading all this, I changed my mind :-)
I think we should just leave out  patch 1 for now. Anthony brought up a
valid point, we want to be able to specify for a device "never boot from it".

>From an s390 point of view, it would even make sense to say
"If the user does not provide a boot index, then the system wont boot.
We leave the system in stopped state." Predictability is more important
than clever guessing in this environment.

Christian