Re: [Qemu-devel] [PATCH 8/8] target-ppc Disentangle ppc64 hash mmu path for cpu_ppc_handle_mmu_fault

[Alexander Graf]

On 12.02.2013, at 03:00, David Gibson wrote:

> cpu_ppc_handle_mmu_fault() calls get_physical_address() (whose behaviour
> depends on MMU type) then, if that fails, issues an appropriate exception
> - which again has a number of dependencies on MMU type.
> 
> This patch starts converting cpu_ppc_handle_mmu_fault() to have a single
> switch on MMU type, calling MMU specific fault handler functions which
> deal with both translation and exception delivery appropriately for the
> MMU type.  We convert 64-bit hash MMUs to this new model, but the
> existing code is left in place for other MMU types for now.
> 
> Signed-off-by: David Gibson <address@hidden>
> ---
> target-ppc/cpu.h        |    2 ++
> target-ppc/mmu-hash64.c |   87 +++++++++++++++++++++++++++++++++++++++++++++++
> target-ppc/mmu_helper.c |   37 +++++++-------------
> 3 files changed, 101 insertions(+), 25 deletions(-)
> 
> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
> index 6143142..da01b06 100644
> --- a/target-ppc/cpu.h
> +++ b/target-ppc/cpu.h
> @@ -1155,6 +1155,8 @@ int ppc_store_slb (CPUPPCState *env, target_ulong rb, 
> target_ulong rs);
> void dump_slb(FILE *f, fprintf_function cpu_fprintf, CPUPPCState *env);
> int ppc_hash64_get_physical_address(CPUPPCState *env, mmu_ctx_t *ctx,
>                                     target_ulong eaddr, int rw, int 
> access_type);
> +int ppc_hash64_handle_mmu_fault(CPUPPCState *env, target_ulong address, int 
> rw,
> +                                int mmu_idx);
> #endif /* defined(TARGET_PPC64) */
> #endif /* !defined(CONFIG_USER_ONLY) */
> void ppc_store_msr (CPUPPCState *env, target_ulong value);
> diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
> index 0f40e0a..ea5fb1f 100644
> --- a/target-ppc/mmu-hash64.c
> +++ b/target-ppc/mmu-hash64.c
> @@ -471,3 +471,90 @@ int ppc_hash64_get_physical_address(CPUPPCState *env, 
> mmu_ctx_t *ctx,
>         return get_segment64(env, ctx, eaddr, rw, access_type);
>     }
> }
> +
> +int ppc_hash64_handle_mmu_fault(CPUPPCState *env, target_ulong address, int 
> rw,
> +                                int mmu_idx)
> +{
> +    mmu_ctx_t ctx;
> +    int access_type;
> +    int ret = 0;
> +
> +    if (rw == 2) {
> +        /* code access */
> +        rw = 0;
> +        access_type = ACCESS_CODE;
> +    } else {
> +        /* data access */
> +        access_type = env->access_type;
> +    }
> +    ret = ppc_hash64_get_physical_address(env, &ctx, address, rw, 
> access_type);
> +    if (ret == 0) {
> +        tlb_set_page(env, address & TARGET_PAGE_MASK,
> +                     ctx.raddr & TARGET_PAGE_MASK, ctx.prot,
> +                     mmu_idx, TARGET_PAGE_SIZE);
> +        ret = 0;
> +    } else if (ret < 0) {
> +        LOG_MMU_STATE(env);
> +        if (access_type == ACCESS_CODE) {
> +            switch (ret) {
> +            case -1:
> +                env->exception_index = POWERPC_EXCP_ISI;
> +                env->error_code = 0x40000000;
> +                break;
> +            case -2:
> +                /* Access rights violation */

These really should become an enum or defines. Something where the thing we 
check on tells us what we're checking for without a comment :).

> +                env->exception_index = POWERPC_EXCP_ISI;
> +                env->error_code = 0x08000000;
> +                break;
> +            case -3:
> +                /* No execute protection violation */
> +                env->exception_index = POWERPC_EXCP_ISI;
> +                env->error_code = 0x10000000;
> +                break;
> +            case -5:
> +                /* No match in segment table */
> +                env->exception_index = POWERPC_EXCP_ISEG;
> +                env->error_code = 0;
> +                break;
> +            }
> +        } else {
> +            switch (ret) {
> +            case -1:
> +                /* No matches in page tables or TLB */
> +                env->exception_index = POWERPC_EXCP_DSI;
> +                env->error_code = 0;
> +                env->spr[SPR_DAR] = address;
> +                if (rw == 1) {
> +                    env->spr[SPR_DSISR] = 0x42000000;
> +                } else {
> +                    env->spr[SPR_DSISR] = 0x40000000;
> +                }
> +                break;
> +            case -2:
> +                /* Access rights violation */
> +                env->exception_index = POWERPC_EXCP_DSI;
> +                env->error_code = 0;
> +                env->spr[SPR_DAR] = address;
> +                if (rw == 1) {
> +                    env->spr[SPR_DSISR] = 0x0A000000;
> +                } else {
> +                    env->spr[SPR_DSISR] = 0x08000000;
> +                }
> +                break;
> +            case -5:
> +                /* No match in segment table */
> +                env->exception_index = POWERPC_EXCP_DSEG;
> +                env->error_code = 0;
> +                env->spr[SPR_DAR] = address;
> +                break;
> +            }
> +        }
> +#if 0

#ifdef DEBUG_MMU?

> +        printf("%s: set exception to %d %02x\n", __func__,
> +               env->exception, env->error_code);
> +#endif
> +        ret = 1;
> +    }
> +
> +    return ret;
> +}
> diff --git a/target-ppc/mmu_helper.c b/target-ppc/mmu_helper.c
> index 98143dd..f8f213b 100644
> --- a/target-ppc/mmu_helper.c
> +++ b/target-ppc/mmu_helper.c
> @@ -1533,6 +1533,18 @@ int cpu_ppc_handle_mmu_fault(CPUPPCState *env, 
> target_ulong address, int rw,
>     int access_type;
>     int ret = 0;
> 
> +    switch (env->mmu_model) {
> +#if defined(TARGET_PPC64)
> +    case POWERPC_MMU_64B:
> +    case POWERPC_MMU_2_06:
> +    case POWERPC_MMU_2_06d:
> +        return ppc_hash64_handle_mmu_fault(env, address, rw, mmu_idx);
> +#endif
> +
> +    default:
> +        ; /* Otherwise fall through to the general code below */
> +    }

Sigh. This too should become a class function. Maybe it is within the scope of 
this patch set after all :). You could keep the "legacy" handling code alive 
and just point the non-converted targets to the existing function. Then 
override the handler for book3s_64 families to ppc_hash64_handle_mmu_fault.


Alex

> +
>     if (rw == 2) {
>         /* code access */
>         rw = 0;
> @@ -1572,11 +1584,6 @@ int cpu_ppc_handle_mmu_fault(CPUPPCState *env, 
> target_ulong address, int rw,
>                     break;
>                 case POWERPC_MMU_32B:
>                 case POWERPC_MMU_601:
> -#if defined(TARGET_PPC64)
> -                case POWERPC_MMU_64B:
> -                case POWERPC_MMU_2_06:
> -                case POWERPC_MMU_2_06d:
> -#endif
>                     env->exception_index = POWERPC_EXCP_ISI;
>                     env->error_code = 0x40000000;
>                     break;
> @@ -1621,13 +1628,6 @@ int cpu_ppc_handle_mmu_fault(CPUPPCState *env, 
> target_ulong address, int rw,
>                 env->exception_index = POWERPC_EXCP_ISI;
>                 env->error_code = 0x10000000;
>                 break;
> -#if defined(TARGET_PPC64)
> -            case -5:
> -                /* No match in segment table */
> -                env->exception_index = POWERPC_EXCP_ISEG;
> -                env->error_code = 0;
> -                break;
> -#endif
>             }
>         } else {
>             switch (ret) {
> @@ -1677,11 +1677,6 @@ int cpu_ppc_handle_mmu_fault(CPUPPCState *env, 
> target_ulong address, int rw,
>                     break;
>                 case POWERPC_MMU_32B:
>                 case POWERPC_MMU_601:
> -#if defined(TARGET_PPC64)
> -                case POWERPC_MMU_64B:
> -                case POWERPC_MMU_2_06:
> -                case POWERPC_MMU_2_06d:
> -#endif
>                     env->exception_index = POWERPC_EXCP_DSI;
>                     env->error_code = 0;
>                     env->spr[SPR_DAR] = address;
> @@ -1776,14 +1771,6 @@ int cpu_ppc_handle_mmu_fault(CPUPPCState *env, 
> target_ulong address, int rw,
>                     break;
>                 }
>                 break;
> -#if defined(TARGET_PPC64)
> -            case -5:
> -                /* No match in segment table */
> -                env->exception_index = POWERPC_EXCP_DSEG;
> -                env->error_code = 0;
> -                env->spr[SPR_DAR] = address;
> -                break;
> -#endif
>             }
>         }
> #if 0
> -- 
> 1.7.10.4
>