Re: [Qemu-devel] [Qemu-ppc] [PATCH RFC] spapr: by-pass SLOF when -kernel is provided

[Laurent Vivier <lvivier@redhat.com>]

On 06/07/2016 09:03, Greg Kurz wrote:
> On Tue, 5 Jul 2016 20:51:41 +0200
> Laurent Vivier <lvivier@redhat.com> wrote:
> 
>> On 05/07/2016 20:44, Greg Kurz wrote:
>>> On Tue,  5 Jul 2016 16:42:37 +0200
>>> Laurent Vivier <lvivier@redhat.com> wrote:
>>>   
>>>> As device-tree is now fully built by QEMU, we don't need SLOF
>>>> anymore if the kernel is provided on the command line.
>>>>
>>>> In this case, don't load SLOF and boot directly into the
>>>> kernel.
>>>>
>>>> This saves at least 5 seconds on the boot sequence.
>>>>  
>>>
>>> The concept looks great so I gave a try with a fedora24 guest.  
>>
>> I did the same test with a rhel7 vmlinuz adn intramfs and it works fine.
>>
>>>
>>> I copied the kernel and initramfs to the host and passed the kernel arguments
>>> taken from grub.
>>>
>>> The kernel starts but the boot sequence stalls at:
>>>
>>> [  OK  ] Reached target Basic System.
>>> [  126.238400] dracut-initqueue[290]: Warning: dracut-initqueue timeout - starting timeout scripts  
>>
>> It happens when the initramfs didn't have the disk driver: do you use
>> the same disk controller with the "-kernel" than the one which was used
>> when the initramfs has been created?
>>
> 
> Yes. The very same QEMU command line (except -kernel/-initrd/-append) works with
> SLOF and fails without SLOF.

I think it works for me because I use spapr-vscsi  and spapr-vlan.

Laurent