Re: [qemu-s390x] [Qemu-devel] [PATCH v2 15/28] s390x/tcg: Fault-safe memset

[Richard Henderson]

On 9/6/19 3:57 AM, David Hildenbrand wrote:
> +    if (likely(desta.haddr1)) {
> +        memset(desta.haddr1, byte, desta.size1);
> +    } else {
> +        for (i = 0; i < desta.size1; i++) {
> +            helper_ret_stb_mmu(env, desta.vaddr1 + i, byte, oi, ra);
> +        }

The only thing perhaps that we could do better here is to re-check
tlb_vaddr_to_host after a singe access.  This would handle NOTDIRTY with a
single iotlb access and then fall back to memset, without re-checking host
address for real mmio after every store.

> +    if (likely(desta.haddr2)) {
> +            memset(desta.haddr2, byte, desta.size2);

Indentation.

> +    } else {
> +        for (i = 0; i < desta.size2; i++) {
> +            helper_ret_stb_mmu(env, desta.vaddr2 + i, byte, oi, ra);
>          }

Likewise wrt NOTDIRTY, which suggests a subroutine to handle a single page?

That said, what's here looks correct so
Reviewed-by: Richard Henderson <address@hidden>

r~