Re: [Qemu-ppc] [PATCH 3/3] ppc/hash64: Fix support for LPCR:ISL

[David Gibson]

On Mon, Jul 04, 2016 at 05:44:11PM +1000, Benjamin Herrenschmidt wrote:
> We need to ignore the segment page size and essentially treat
> all pages as coming from a 4K segment.
> 
> Signed-off-by: Benjamin Herrenschmidt <address@hidden>

I've adjusted this for my different version of 1/3 and applied to
ppc-for-2.7.

> 
> # Conflicts:
> #     target-ppc/mmu-hash64.c
> ---
>  target-ppc/mmu-hash64.c | 29 +++++++++++++++++++----------
>  1 file changed, 19 insertions(+), 10 deletions(-)
> 
> diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
> index 87a2c26..878a0a0 100644
> --- a/target-ppc/mmu-hash64.c
> +++ b/target-ppc/mmu-hash64.c
> @@ -487,9 +487,10 @@ static unsigned hpte_decode_psize(const struct 
> ppc_one_seg_page_size *sps,
>  }
>  
>  static target_long ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash,
> -                                          ppc_slb_t *slb, target_ulong ptem,
> -                                          ppc_hash_pte64_t *pte,
> -                                          unsigned *pshift)
> +                                      const struct ppc_one_seg_page_size 
> *sps,
> +                                      target_ulong ptem,
> +                                      ppc_hash_pte64_t *pte,
> +                                      unsigned *pshift)
>  {
>      CPUPPCState *env = &cpu->env;
>      target_ulong pte_index, pte0, pte1;
> @@ -511,7 +512,7 @@ static target_long ppc_hash64_pteg_search(PowerPCCPU 
> *cpu, hwaddr hash,
>              pte1 = ppc_hash64_load_hpte1(cpu, token, i);
>  
>              /* Decode the actual page size */
> -            *pshift = hpte_decode_psize(slb->sps, pte0, pte1);
> +            *pshift = hpte_decode_psize(sps, pte0, pte1);
>  
>              /* If there is no match, ignore the PTE, it could simply be
>               * for a different segment size encoding and the architecture
> @@ -544,23 +545,31 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu,
>      hwaddr pte_offset;
>      hwaddr hash;
>      uint64_t vsid, epnmask, epn, ptem;
> +    const struct ppc_one_seg_page_size *sps = slb->sps;
>  
>      /* The SLB store path should prevent any bad page size encodings
>       * getting in there, so: */
> -    assert(slb->sps);
> +    assert(sps);
>  
> -    epnmask = ~((1ULL << slb->sps->page_shift) - 1);
> +    /* If ISL is set in LPCR we need to clamp the page size to 4K */
> +    if (env->spr[SPR_LPCR] & LPCR_ISL) {
> +        /* We assume that when using TCG, 4k is first entry of SPS */
> +        sps = &env->sps.sps[0];
> +        assert(sps->page_shift == 12);
> +    }
> +
> +    epnmask = ~((1ULL << sps->page_shift) - 1);
>  
>      if (slb->vsid & SLB_VSID_B) {
>          /* 1TB segment */
>          vsid = (slb->vsid & SLB_VSID_VSID) >> SLB_VSID_SHIFT_1T;
>          epn = (eaddr & ~SEGMENT_MASK_1T) & epnmask;
> -        hash = vsid ^ (vsid << 25) ^ (epn >> slb->sps->page_shift);
> +        hash = vsid ^ (vsid << 25) ^ (epn >> sps->page_shift);
>      } else {
>          /* 256M segment */
>          vsid = (slb->vsid & SLB_VSID_VSID) >> SLB_VSID_SHIFT;
>          epn = (eaddr & ~SEGMENT_MASK_256M) & epnmask;
> -        hash = vsid ^ (epn >> slb->sps->page_shift);
> +        hash = vsid ^ (epn >> sps->page_shift);
>      }
>      ptem = (slb->vsid & SLB_VSID_PTEM) | ((epn >> 16) & HPTE64_V_AVPN);
>      ptem |= HPTE64_V_VALID;
> @@ -577,7 +586,7 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu,
>              " vsid=" TARGET_FMT_lx " ptem=" TARGET_FMT_lx
>              " hash=" TARGET_FMT_plx "\n",
>              env->htab_base, env->htab_mask, vsid, ptem,  hash);
> -    pte_offset = ppc_hash64_pteg_search(cpu, hash, slb,
> +    pte_offset = ppc_hash64_pteg_search(cpu, hash, sps,
>                                          ptem, pte, pshift);
>  
>      if (pte_offset == -1) {
> @@ -589,7 +598,7 @@ static hwaddr ppc_hash64_htab_lookup(PowerPCCPU *cpu,
>                  " hash=" TARGET_FMT_plx "\n", env->htab_base,
>                  env->htab_mask, vsid, ptem, ~hash);
>  
> -        pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb,
> +        pte_offset = ppc_hash64_pteg_search(cpu, ~hash, sps,
>                                              ptem, pte, pshift);
>      }
>  

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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