Re: [Qemu-devel] [PATCH 12/26] target/moxie: Convert to CPUClass::tlb_fill

[Peter Maydell]

On Wed, 3 Apr 2019 at 04:52, Richard Henderson
<address@hidden> wrote:
>
> Cc: Anthony Green <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---

>
> -#if defined(CONFIG_USER_ONLY)
> -
> -void moxie_cpu_do_interrupt(CPUState *cs)
> -{
> -    CPUState *cs = CPU(moxie_env_get_cpu(env));
> -
> -    cs->exception_index = -1;
> -}
> -
> -int moxie_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size,
> -                               int rw, int mmu_idx)
> -{
> -    MoxieCPU *cpu = MOXIE_CPU(cs);
> -
> -    cs->exception_index = 0xaa;
> -    cpu->env.debug1 = address;
> -    cpu_dump_state(cs, stderr, fprintf, 0);
> -    return 1;
> -}

The commit message should say that we can just delete the old
user-only code because we don't have a moxie-linux-user config.

> -
> -#else /* !CONFIG_USER_ONLY */
> -
> -int moxie_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int size,
> -                               int rw, int mmu_idx)
> +bool moxie_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
> +                        MMUAccessType access_type, int mmu_idx,
> +                        bool probe, uintptr_t retaddr)
>  {
>      MoxieCPU *cpu = MOXIE_CPU(cs);
>      CPUMoxieState *env = &cpu->env;
>      MoxieMMUResult res;
>      int prot, miss;
> -    target_ulong phy;
> -    int r = 1;
>
>      address &= TARGET_PAGE_MASK;
>      prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
> -    miss = moxie_mmu_translate(&res, env, address, rw, mmu_idx);
> -    if (miss) {
> -        /* handle the miss.  */
> -        phy = 0;
> -        cs->exception_index = MOXIE_EX_MMU_MISS;
> -    } else {
> -        phy = res.phy;
> -        r = 0;
> +    miss = moxie_mmu_translate(&res, env, address, access_type, mmu_idx);
> +    if (likely(!miss)) {
> +        tlb_set_page(cs, address, res.phy, prot, mmu_idx, TARGET_PAGE_SIZE);
> +        return true;
> +    }
> +    if (probe) {
> +        return false;
>      }
> -    tlb_set_page(cs, address, phy, prot, mmu_idx, TARGET_PAGE_SIZE);
> -    return r;
> -}
>
> +    cs->exception_index = MOXIE_EX_MMU_MISS;
> +    cpu_loop_exit_restore(cs, retaddr);
> +}

The old code was calling tlb_set_page() even on an MMU miss,
and the new could doesn't do that. This looks like it was
a bug to me, but if we're fixing bugs we should mention them
in the commit message, at least.

Otherwise
Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM