[PATCH v2 07/13] powerpc: Increase NR_IRQS range to support more KVM guests

[Cédric Le Goater]

On 12/11/20 12:51 AM, Michael Ellerman wrote:
> Cédric Le Goater <clg at kaod.org> writes:
>> PowerNV systems can handle up to 4K guests and 1M interrupt numbers
>> per chip. Increase the range of allowed interrupts to support a larger
>> number of guests.
>>
>> Reviewed-by: Greg Kurz <groug at kaod.org>
>> Signed-off-by: Cédric Le Goater <clg at kaod.org>
>> ---
>>  arch/powerpc/Kconfig | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 5181872f9452..c250fbd430d1 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -66,7 +66,7 @@ config NEED_PER_CPU_PAGE_FIRST_CHUNK
>>  
>>  config NR_IRQS
>>  	int "Number of virtual interrupt numbers"
>> -	range 32 32768
>> +	range 32 1048576
>>  	default "512"
>>  	help
>>  	  This defines the number of virtual interrupt numbers the kernel
> 
> We should really do what other arches do, and size this appropriately
> based on the config, rather than asking users to guess what size they
> need.
> 
> But I guess I'll take this for now, and we can do something fancier
> later.

I was thinking on adding a property to OPAL to size the HW interrupt 
number space. Is that it ?  That would be good because it's increasing
from 20bits on P9 to 24bits on P10.

I am checking other arches.

Thanks,

C.