Re: [PATCH 3/6] target/ppc: Fix instruction loading endianness in alignment interrupt

[Fabiano Rosas]

Hi Nick,

> powerpc ifetch endianness depends on MSR[LE] so it has to byteswap
> after cpu_ldl_code(). This corrects DSISR bits in alignment
> interrupts when running in little endian mode.
>

Just a thought, we have these tests that perhaps could have caught
this:  https://github.com/legoater/pnv-test

Despite the name they do have (some) support to pseries as well. Not
sure how the P8 support is these days though.

> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  target/ppc/excp_helper.c | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index 287659c74d..5f0e363363 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -133,6 +133,31 @@ static void dump_hcall(CPUPPCState *env)
>                    env->nip);
>  }
>  
> +/* Return true iff byteswap is needed in a scalar memop */
> +static inline bool need_byteswap(CPUArchState *env)
> +{
> +#if TARGET_BIG_ENDIAN

TARGET_BIG_ENDIAN is always set for softmmu mode. See
configs/targets/ppc64-softmmu.mak

> +     return !!(env->msr & ((target_ulong)1 << MSR_LE));
> +#else
> +     return !(env->msr & ((target_ulong)1 << MSR_LE));
> +#endif
> +}
> +
> +static uint32_t ppc_ldl_code(CPUArchState *env, abi_ptr addr)
> +{
> +    uint32_t insn = cpu_ldl_code(env, addr);
> +#if TARGET_BIG_ENDIAN
> +    if (env->msr & ((target_ulong)1 << MSR_LE)) {
> +        insn = bswap32(insn);
> +    }
> +#else
> +    if (!(env->msr & ((target_ulong)1 << MSR_LE))) {
> +        insn = bswap32(insn);
> +    }
> +#endif
> +    return insn;
> +}
> +
>  static void ppc_excp_debug_sw_tlb(CPUPPCState *env, int excp)
>  {
>      const char *es;
> @@ -3097,7 +3122,7 @@ void ppc_cpu_do_unaligned_access(CPUState *cs, vaddr 
> vaddr,
>  
>      /* Restore state and reload the insn we executed, for filling in DSISR.  
> */
>      cpu_restore_state(cs, retaddr);
> -    insn = cpu_ldl_code(env, env->nip);
> +    insn = ppc_ldl_code(env, env->nip);
>  
>      switch (env->mmu_model) {
>      case POWERPC_MMU_SOFT_4xx: