Re: [Qemu-devel] [PULL 14/14] ppc/hash64: Fix support for LPCR:ISL

[Benjamin Herrenschmidt]

On Tue, 2016-07-05 at 15:10 +1000, David Gibson wrote:
> From: Benjamin Herrenschmidt <address@hidden>
> 
> We need to ignore the segment page size and essentially treat
> all pages as coming from a 4K segment.

NAK

The arguments are still wrong to ppc_hash64_pteg_search

> Signed-off-by: Benjamin Herrenschmidt <address@hidden>
> [dwg: Adjusted for differencesin my version of the prereq patches]
> Signed-off-by: David Gibson <address@hidden>
> ---
>  target-ppc/mmu-hash64.c | 27 +++++++++++++++++++--------
>  1 file changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
> index 7f31444..bcd1c9d 100644
> --- a/target-ppc/mmu-hash64.c
> +++ b/target-ppc/mmu-hash64.c
> @@ -488,7 +488,8 @@ static unsigned hpte_page_shift(const struct
> ppc_one_seg_page_size *sps,
>  }
>  
>  static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, hwaddr hash,
> -                                     ppc_slb_t *slb, target_ulong
> ptem,
> +                                     const struct
> ppc_one_seg_page_size *sps,
> +                                     target_ulong ptem,
>                                       ppc_hash_pte64_t *pte, unsigned
> *pshift)
>  {
>      CPUPPCState *env = &cpu->env;
> @@ -508,7 +509,7 @@ static hwaddr ppc_hash64_pteg_search(PowerPCCPU
> *cpu, hwaddr hash,
>  
>          /* This compares V, B, H (secondary) and the AVPN */
>          if (HPTE64_V_COMPARE(pte0, ptem)) {
> -            *pshift = hpte_page_shift(slb->sps, pte0, pte1);
> +            *pshift = hpte_page_shift(sps, pte0, pte1);
>              /*
>               * If there is no match, ignore the PTE, it could simply
>               * be for a different segment size encoding and the
> @@ -543,23 +544,31 @@ 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;
> @@ -576,7 +585,8 @@ 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, ptem, pte,
> pshift);
> +    pte_offset = ppc_hash64_pteg_search(cpu, hash, slb->sps,
> +                                        ptem, pte, pshift);
>  
>      if (pte_offset == -1) {
>          /* Secondary PTEG lookup */
> @@ -587,7 +597,8 @@ 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, ptem,
> pte, pshift);
> +        pte_offset = ppc_hash64_pteg_search(cpu, ~hash, slb->sps,
> +                                            ptem, pte, pshift);
>      }
>  
>      return pte_offset;