On Tue, 2017-08-15 at 22:10 +1000, Nicholas Piggin wrote: > On Mon, 14 Aug 2017 23:13:07 +1000 > Benjamin Herrenschmidt <b...@au1.ibm.com> wrote: > > > On Mon, 2017-08-14 at 22:49 +1000, Michael Ellerman wrote: > > > > - /* > > > > - * We limit the allocation that depend on ppc64_rma_size > > > > - * to first_memblock_size. We also clamp it to 1GB to > > > > - * avoid some funky things such as RTAS bugs. > > > > > > That comment about RTAS is 7 years old, and I'm pretty sure it was a > > > historical note when it was written. > > > > > > I'm inclined to drop it and if we discover new bugs with RTAS on Power9 > > > then we can always put it back. > > > > Arent' we using a 32-bit RTAS ? (Afaik there's a 64-bit one, we just > > never used it ..). In this case we need to at least clamp to 2G (no > > trust RTAS doing unsigned properly). > > Is there any allocation not covered by RTAS_INSTANTIATE_MAX?
Not sure, we have to audit. Talking about all this with mpe today, I think we just need to make sure that anything that has a restriction uses a specific identifier for *that* restriction rather than just blindly "rma". For example, seg0_limit for segment 0 in HPT. In the case of PACAs, we would create a specific limit that is min(seg0_limit,rma) for pseries and -1 for powernv. etc.. The RMA limit can then become either strictly a pseries thing, or be initialized to -1 on powernv (or max mem). Ben.
