[SeaBIOS] [PATCH 1/2] scsi: ensure LUN0 is added first

[Paolo Bonzini]

On 27/09/2017 16:35, Kevin O'Connor wrote:
> On Wed, Sep 27, 2017 at 04:15:49PM +0200, Paolo Bonzini wrote:
>> On 27/09/2017 15:58, Kevin O'Connor wrote:
>>> On Wed, Sep 27, 2017 at 09:36:01AM +0200, Paolo Bonzini wrote:
>>>> On 21/06/2017 00:44, Kevin O'Connor wrote:
>>>>>> Yes, I think so.  I'm not sure why virtqueues are allocated
>>>>>> in low memory.  Either cargo culting, or a remain of when
>>>>>> virtio was a 16-bit driver, if it ever was.
>>>>> The 'struct drive_s' storage currently must be allocated in the
>>>>> f-segment so that the disk.c code can access some critical details of
>>>>> mapped drives when in 16bit mode.  However, we could change the code
>>>>> to allocate that data separately from the controller specific data and
>>>>> then move the controller specific data to a larger memory pool. 
>>>>
>>>> I don't think this is the issue.  virtqueues actually have been
>>>> allocated with memalign_high since 2015 (commit 6cfebb4e).
>>>>
>>>> virtio-blk is allocating 68 fseg bytes for the controller-specific data,
>>>> virtio-scsi only 16.  struct drive_s is about 40 bytes long.
>>>
>>> What is the test case for reproducing the problem?
> [...]
>> respects it.  The reason is that with "manydisks" you get many FSEG
>> allocation failures in virtio_scsi_init_lun.
> 
> I can confirm it fails on SeaBIOS master, but works on the
> "work-drive-lowmem-20170711" branch.
> 
> I didn't want to commit that branch without confirming it fixed the
> underlying problem.  Is this sufficient confirmation?

Yes, I tried with more disks and it works with about 900.  I guess
that's fine.

Paolo