Re: [Qemu-devel] [PATCH v2 2/3] PPC: Allow little-endian user mode.

[Alexander Graf <agraf@suse.de>]

On 10.05.14 11:16, Doug Kwan wrote:
> This allow running PPC64 little-endian in user mode if target is configured
> that way.  In PPC64 LE user mode we set MSR.LE during initialization.
> Overhaul handling of byteswapping in code generation and mem helpers.
>
> Signed-off-by: Doug Kwan <dougkwan@google.com>
> ---
>   target-ppc/mem_helper.c     |  25 ++++++--
>   target-ppc/translate.c      | 150 +++++++++++++++++---------------------------
>   target-ppc/translate_init.c |   9 +++
>   3 files changed, 89 insertions(+), 95 deletions(-)
>

[...]

> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index 4d94015..84381ae 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -8418,6 +8418,9 @@ static void ppc_cpu_reset(CPUState *s)
>       msr |= (target_ulong)1 << MSR_VR; /* Allow altivec usage */
>       msr |= (target_ulong)1 << MSR_SPE; /* Allow SPE usage */
>       msr |= (target_ulong)1 << MSR_PR;
> +#if !defined(TARGET_WORDS_BIGENDIAN)
> +    msr |= (target_ulong)1 << MSR_LE; /* Little-endian user mode */
> +#endif
>   #endif
>   
>   #if defined(TARGET_PPC64)
> @@ -8461,6 +8464,12 @@ static void ppc_cpu_reset(CPUState *s)
>   
>       /* Flush all TLBs */
>       tlb_flush(s, 1);
> +
> +#if defined(CONFIG_USER_ONLY) && !defined(TARGET_WORDS_BIGENDIAN)
> +    if (!msr_le) {
> +        cpu_abort(CPU(cpu), "Cannot set QEMU to little-endian user mode\n");

We don't have this check the other way around, so why do we need it 
here? How do you ever get to this?


Alex