Emilio G. Cota <c...@braap.org> writes:
> On Fri, Jul 01, 2016 at 17:16:09 +0100, Alex Bennée wrote:
>> From: Sergey Fedorov <serge.f...@gmail.com>
> (snip)
>> @@ -333,7 +338,7 @@ static inline TranslationBlock *tb_find_fast(CPUState
>> *cpu,
>> is executed. */
>> cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
>> tb_lock();
>> - tb = cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)];
>> + tb = atomic_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]);
>> if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
>> tb->flags != flags)) {
>> tb = tb_find_slow(cpu, pc, cs_base, flags);
>> diff --git a/translate-all.c b/translate-all.c
>> index eaa95e4..1fcfe79 100644
>> --- a/translate-all.c
>> +++ b/translate-all.c
>> @@ -1004,11 +1004,16 @@ void tb_phys_invalidate(TranslationBlock *tb,
>> tb_page_addr_t page_addr)
>> invalidate_page_bitmap(p);
>> }
>>
>> + /* Ensure that we won't find the TB in the shared hash table
>> + * if we con't see it in CPU's local cache.
>
> s/con't/can't/
>
>> + * Pairs with smp_rmb() in tb_find_slow(). */
>> + smp_wmb();
>
> This fence is already embedded in qht_remove, since it internally
> calls seqlock_write_end() on a successful removal, so we could get
> away with a comment instead of emitting a redundant fence.
> However, if qht ever changed its implementation this would have
> to be taken into account. So I'd be OK with emitting the
> fence here too.
>
>> +
>> /* remove the TB from the hash list */
>> h = tb_jmp_cache_hash_func(tb->pc);
>> CPU_FOREACH(cpu) {
>> if (cpu->tb_jmp_cache[h] == tb) {
>
> Missing atomic_read here: if (atomic_read(cpu->tb_jmp_cache[...])) {
Oops, good catch.
>
>> - cpu->tb_jmp_cache[h] = NULL;
>> + atomic_set(&cpu->tb_jmp_cache[h], NULL);
>
> Other than that,
>
> Reviewed-by: Emilio G. Cota <c...@braap.org>
--
Alex Bennée
