Re: [PATCH 2/3] powperc/mm: read TLB Block Invalidate Characteristics

[Laurent Dufour]

Le 13/09/2019 Ã 04:00, Aneesh Kumar K.V a ÃcritÂ:
> On 9/13/19 12:56 AM, Laurent Dufour wrote:
> > Le 12/09/2019 Ã 16:44, Aneesh Kumar K.V a ÃcritÂ:
> > > Laurent Dufour <ldufour@xxxxxxxxxxxxx> writes:
>
> > > > +
> > > > +ÂÂÂ idx = 2;
> > > > +ÂÂÂ while (idx < len) {
> > > > +ÂÂÂÂÂÂÂ unsigned int block_size = local_buffer[idx++];
> > > > +ÂÂÂÂÂÂÂ unsigned int npsize;
> > > > +
> > > > +ÂÂÂÂÂÂÂ if (!block_size)
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ break;
> > > > +
> > > > +ÂÂÂÂÂÂÂ block_size = 1 << block_size;
> > > > +ÂÂÂÂÂÂÂ if (block_size != 8)
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ /* We only support 8 bytes size TLB invalidate buffer */
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ pr_warn("Unsupported H_BLOCK_REMOVE block size : %d\n",
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ block_size);
> > >
> > > Should we skip setting block size if we find block_size != 8? Also can
> > > we avoid doing that pr_warn in loop and only warn if we don't find
> > > block_size 8 in the invalidate characteristics array?
> >
> > My idea here is to fully read and process the data returned by the hcall, 
> > and to put the limitation to 8 when checking before calling H_BLOCK_REMOVE.
> > The warning is there because I want it to be displayed once at boot.
>
>
> Can we have two block size reported for the same base page size/actual page 
> size combination? If so we will overwrite the hblk[actual_psize] ?

In check_lp_set_hblk() I'm only keeping the bigger one.

> > > > +
> > > > +ÂÂÂÂÂÂÂ for (npsize = local_buffer[idx++];Â npsize > 0; npsize--)
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ check_lp_set_hblk((unsigned int) local_buffer[idx++],
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ block_size);
> > > > +ÂÂÂ }
> > > > +
> > > > +ÂÂÂ for (bpsize = 0; bpsize < MMU_PAGE_COUNT; bpsize++)
> > > > +ÂÂÂÂÂÂÂ for (idx = 0; idx < MMU_PAGE_COUNT; idx++)
> > > > +ÂÂÂÂÂÂÂÂÂÂÂ if (mmu_psize_defs[bpsize].hblk[idx])
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pr_info("H_BLOCK_REMOVE supports base psize:%d 
> > > > psize:%d block size:%d",
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ bpsize, idx,
> > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ mmu_psize_defs[bpsize].hblk[idx]);
> > > > +
> > > > +ÂÂÂ return 0;
> > > > +}
> > > > +machine_arch_initcall(pseries, read_tlbbi_characteristics);
> > > > +
> > > > Â /*
> > > > ÂÂ * Take a spinlock around flushes to avoid bouncing the hypervisor tlbie
> > > > ÂÂ * lock.
>
> -aneesh