Re: [PATCH for-7.2 14/21] accel/tcg: Hoist get_page_addr_code out of tb_lookup

[Richard Henderson]

On 8/17/22 06:08, Ilya Leoshkevich wrote:
> +static void cpu_tb_jmp_cache_remove(TranslationBlock *tb)
> +{
> +    CPUState *cpu;
> +    uint32_t h;
> +
> +    /* remove the TB from the hash list */
> +    if (TARGET_TB_PCREL) {
> +        /* Any TB may be at any virtual address */
> +        CPU_FOREACH(cpu) {
> +            cpu_tb_jmp_cache_clear(cpu);
> +        }

This comment is not currently true for user-only.  Although there's an outstanding bug 
report about our failure to manage virtual aliasing in user-only...

> +            PAGE_FOR_EACH_TB(p, tb, n) {
> +                cpu_tb_jmp_cache_remove(tb);
> +            }

You wouldn't want to call cpu_tb_jmp_cache_clear() 99 times for the 99 tb's on 
the page.

For user-only, I think mprotect is rare enough that just clearing the whole cache once is 
sufficient.


r~