Re: [PATCH v2 1/1] powerpc/iommu: Enable remaining IOMMU Pagesizes present in LoPAR

From: Michael Ellerman
Date: Thu Apr 08 2021 - 05:08:27 EST


Leonardo Bras <leobras.c@xxxxxxxxx> writes:
> On Thu, 2021-04-08 at 03:20 -0300, Leonardo Bras wrote:
>> > > +#define QUERY_DDW_PGSIZE_4K 0x01
>> > > +#define QUERY_DDW_PGSIZE_64K 0x02
>> > > +#define QUERY_DDW_PGSIZE_16M 0x04
>> > > +#define QUERY_DDW_PGSIZE_32M 0x08
>> > > +#define QUERY_DDW_PGSIZE_64M 0x10
>> > > +#define QUERY_DDW_PGSIZE_128M 0x20
>> > > +#define QUERY_DDW_PGSIZE_256M 0x40
>> > > +#define QUERY_DDW_PGSIZE_16G 0x80
>> >
>> > I'm not sure the #defines really gain us much vs just putting the
>> > literal values in the array below?
>>
>> My v1 did not use the define approach, what do you think of that?
>> http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20210322190943.715368-1-leobras.c@xxxxxxxxx/
>>
>>
> (of course, it would be that without the pageshift defines also, using
> the __builtin_ctz() approach suggested by Alexey.)

Yeah I think I like that better.

cheers