Re: [PATCH v7 11/17] target/ppc: Don't store VRMA SLBE persistently

[Greg Kurz <groug@kaod.org>]

On Tue,  3 Mar 2020 14:43:45 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> Currently, we construct the SLBE used for VRMA translations when the LPCR
> is written (which controls some bits in the SLBE), then use it later for
> translations.
> 
> This is a bit complex and confusing - simplify it by simply constructing
> the SLBE directly from the LPCR when we need it.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  target/ppc/cpu.h        |  3 --
>  target/ppc/mmu-hash64.c | 92 ++++++++++++++++-------------------------
>  2 files changed, 35 insertions(+), 60 deletions(-)
> 
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index f9871b1233..5a55fb02bd 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -1044,9 +1044,6 @@ struct CPUPPCState {
>      uint32_t flags;
>      uint64_t insns_flags;
>      uint64_t insns_flags2;
> -#if defined(TARGET_PPC64)
> -    ppc_slb_t vrma_slb;
> -#endif
>  
>      int error_code;
>      uint32_t pending_interrupts;
> diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
> index 4fd7b7ee74..34f6009b1e 100644
> --- a/target/ppc/mmu-hash64.c
> +++ b/target/ppc/mmu-hash64.c
> @@ -784,11 +784,41 @@ static target_ulong rmls_limit(PowerPCCPU *cpu)
>      return rma_sizes[rmls];
>  }
>  
> +static int build_vrma_slbe(PowerPCCPU *cpu, ppc_slb_t *slb)
> +{
> +    CPUPPCState *env = &cpu->env;
> +    target_ulong lpcr = env->spr[SPR_LPCR];
> +    uint32_t vrmasd = (lpcr & LPCR_VRMASD) >> LPCR_VRMASD_SHIFT;
> +    target_ulong vsid = SLB_VSID_VRMA | ((vrmasd << 4) & SLB_VSID_LLP_MASK);
> +    int i;
> +
> +    for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
> +        const PPCHash64SegmentPageSizes *sps = &cpu->hash64_opts->sps[i];
> +
> +        if (!sps->page_shift) {
> +            break;
> +        }
> +
> +        if ((vsid & SLB_VSID_LLP_MASK) == sps->slb_enc) {
> +            slb->esid = SLB_ESID_V;
> +            slb->vsid = vsid;
> +            slb->sps = sps;
> +            return 0;
> +        }
> +    }
> +
> +    error_report("Bad page size encoding in LPCR[VRMASD]; LPCR=0x"
> +                 TARGET_FMT_lx"\n", lpcr);
> +
> +    return -1;
> +}
> +
>  int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
>                                  int rwx, int mmu_idx)
>  {
>      CPUState *cs = CPU(cpu);
>      CPUPPCState *env = &cpu->env;
> +    ppc_slb_t vrma_slbe;
>      ppc_slb_t *slb;
>      unsigned apshift;
>      hwaddr ptex;
> @@ -827,8 +857,8 @@ int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
>              }
>          } else if (ppc_hash64_use_vrma(env)) {
>              /* Emulated VRMA mode */
> -            slb = &env->vrma_slb;
> -            if (!slb->sps) {
> +            slb = &vrma_slbe;
> +            if (build_vrma_slbe(cpu, slb) != 0) {
>                  /* Invalid VRMA setup, machine check */
>                  cs->exception_index = POWERPC_EXCP_MCHECK;
>                  env->error_code = 0;
> @@ -976,6 +1006,7 @@ skip_slb_search:
>  hwaddr ppc_hash64_get_phys_page_debug(PowerPCCPU *cpu, target_ulong addr)
>  {
>      CPUPPCState *env = &cpu->env;
> +    ppc_slb_t vrma_slbe;
>      ppc_slb_t *slb;
>      hwaddr ptex, raddr;
>      ppc_hash_pte64_t pte;
> @@ -997,8 +1028,8 @@ hwaddr ppc_hash64_get_phys_page_debug(PowerPCCPU *cpu, target_ulong addr)
>              return raddr | env->spr[SPR_HRMOR];
>          } else if (ppc_hash64_use_vrma(env)) {
>              /* Emulated VRMA mode */
> -            slb = &env->vrma_slb;
> -            if (!slb->sps) {
> +            slb = &vrma_slbe;
> +            if (build_vrma_slbe(cpu, slb) != 0) {
>                  return -1;
>              }
>          } else {
> @@ -1037,65 +1068,12 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu, target_ulong ptex,
>      cpu->env.tlb_need_flush = TLB_NEED_GLOBAL_FLUSH | TLB_NEED_LOCAL_FLUSH;
>  }
>  
> -static void ppc_hash64_update_vrma(PowerPCCPU *cpu)
> -{
> -    CPUPPCState *env = &cpu->env;
> -    const PPCHash64SegmentPageSizes *sps = NULL;
> -    target_ulong esid, vsid, lpcr;
> -    ppc_slb_t *slb = &env->vrma_slb;
> -    uint32_t vrmasd;
> -    int i;
> -
> -    /* First clear it */
> -    slb->esid = slb->vsid = 0;
> -    slb->sps = NULL;
> -
> -    /* Is VRMA enabled ? */
> -    if (!ppc_hash64_use_vrma(env)) {
> -        return;
> -    }
> -
> -    /*
> -     * Make one up. Mostly ignore the ESID which will not be needed
> -     * for translation
> -     */
> -    lpcr = env->spr[SPR_LPCR];
> -    vsid = SLB_VSID_VRMA;
> -    vrmasd = (lpcr & LPCR_VRMASD) >> LPCR_VRMASD_SHIFT;
> -    vsid |= (vrmasd << 4) & (SLB_VSID_L | SLB_VSID_LP);
> -    esid = SLB_ESID_V;
> -
> -    for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
> -        const PPCHash64SegmentPageSizes *sps1 = &cpu->hash64_opts->sps[i];
> -
> -        if (!sps1->page_shift) {
> -            break;
> -        }
> -
> -        if ((vsid & SLB_VSID_LLP_MASK) == sps1->slb_enc) {
> -            sps = sps1;
> -            break;
> -        }
> -    }
> -
> -    if (!sps) {
> -        error_report("Bad page size encoding esid 0x"TARGET_FMT_lx
> -                     " vsid 0x"TARGET_FMT_lx, esid, vsid);
> -        return;
> -    }
> -
> -    slb->vsid = vsid;
> -    slb->esid = esid;
> -    slb->sps = sps;
> -}
> -
>  void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong val)
>  {
>      PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
>      CPUPPCState *env = &cpu->env;
>  
>      env->spr[SPR_LPCR] = val & pcc->lpcr_mask;
> -    ppc_hash64_update_vrma(cpu);
>  }
>  
>  void helper_store_lpcr(CPUPPCState *env, target_ulong val)