Re: [Qemu-devel] [Qemu-ppc] [GIT PULL for qemu-pseries REPOST] pseries: Update SLOF firmware image

[Aravinda Prasad <aravinda@linux.vnet.ibm.com>]

On Tuesday 13 August 2019 07:47 PM, David Gibson wrote:
> On Tue, Aug 13, 2019 at 01:00:24PM +0530, Aravinda Prasad wrote:
>>
>>
>> On Monday 12 August 2019 03:38 PM, David Gibson wrote:
>>> On Mon, Aug 05, 2019 at 02:14:39PM +0530, Aravinda Prasad wrote:
>>>> Alexey/David,
>>>>
>>>> With the SLOF changes, QEMU cannot resize the RTAS blob. Resizing is
>>>> required for FWNMI support which extends the RTAS blob to include an
>>>> error log upon a machine check.
>>>>
>>>> The check to valid RTAS buffer fails in the guest because the rtas-size
>>>> updated in QEMU is not reflecting in the guest.
>>>>
>>>> Any workaround for this?
>>>
>>> Well, we should still be able to do it, it just means fwnmi would need
>>> a SLOF change.  It's an inconvenience, but not really a big deal.
>>
>> Yes. Alexey and I were discussing about the following changes to SLOf:
>>
>> diff --git a/lib/libhvcall/hvcall.S b/lib/libhvcall/hvcall.S
>> index b19f6dbeff2c..880d29a29122 100644
>> --- a/lib/libhvcall/hvcall.S
>> +++ b/lib/libhvcall/hvcall.S
>> @@ -134,6 +134,7 @@ ENTRY(hv_rtas)
>>         ori     r3,r3,KVMPPC_H_RTAS@l
>>         HVCALL
>>         blr
>> +    .space 2048
>>         .globl hv_rtas_size
>>  hv_rtas_size:
>>         .long . - hv_rtas;
>>
>>
>> But this will statically reserve space for RTAS even when
>> SPAPR_CAP_FWNMI_MCE is OFF.
> 
> Sure.  We could flag that in the DT somehow, and have SLOF reserve the
> space conditionally.
> 
> Or we could just ignore it. 2 kiB is miniscule compared to our minimum
> guest size, and our current RTAS is microscopic compared to PowerVM.

I also think so, 2kiB is miniscule so we can allocate it statically.

Alexey,

Can you please include the above one line fix to SLOF?

> 
> 

-- 
Regards,
Aravinda