Re: [Qemu-devel] [PATCH v5 2/3] softmmu: Add probe_write()

[Peter Maydell]

On 26 May 2015 at 17:49, Yongbok Kim <address@hidden> wrote:
> Add probe_write() forces a tlb_fill if the specified guest virtual
> index isn't in the TCG softmmu TLB.

Surely the point is not to fill the TLB but to raise an
exception if the address is not writable?

> +#if DATA_SIZE == 1
> +/*
> + * Force a tlb_fill if the specified guest virtual index isn't in the TCG
> + * softmmu TLB.
> + */
> +void probe_write(CPUArchState *env, target_ulong addr, int mmu_idx,
> +                 uintptr_t retaddr)
> +{
> +    int index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
> +    target_ulong tlb_addr = env->tlb_table[mmu_idx][index].addr_write;
> +
> +    if ((addr & TARGET_PAGE_MASK)
> +        != (tlb_addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
> +        /* TLB entry is for a different page */
> +        if (!VICTIM_TLB_HIT(addr_write)) {
> +            tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_STORE, mmu_idx, 
> retaddr);
> +        }
> +    }
> +}
> +#endif
>  #endif /* !defined(SOFTMMU_CODE_ACCESS) */

I think this code does what you want, but the comments are
rather misleading...

-- PMM