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

[Nikunj A Dadhania]

Alexey Kardashevskiy <address@hidden> writes:

> [ Unknown signature status ]
> On 06/07/16 11:35, David Gibson wrote:
>> On Tue, Jul 05, 2016 at 04:42:37PM +0200, Laurent Vivier 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.
>>>
>>> Signed-off-by: Laurent Vivier <address@hidden>
>> 
>> I'm not comfortable applying this.  We actually used to do this ages
>> ago, but changed to always running through SLOF, and there were
>> reasons for doing so.
>> 
>> I don't remember exactly what they were, but I think it boiled down to
>> slight differences in state between booting from SLOF and booting
>> without SLOF leading to confusing errors from the guest kernel.
>> 
>
> PCI resource allocation is still done by SLOF (however having them not set
> will trigger allocation in the guest but this is rather unexpected
> workaround than a feature);

I am not sure that works well, i had a work around in qemu for this to get
triggered in guest kernel.

> "client-architecture-support" won't work
> without SLOF either (i.e. compatibile PowerISA 2.0x CPUs).

Right.

Regards
Nikunj