On Wed, Apr 26, 2017 at 10:40:45 +0200, Richard Henderson wrote:
> On 04/26/2017 08:23 AM, Emilio G. Cota wrote:
(snip)
> >+ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
> >+ tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(addr)]);
> >+ if (likely(tb && tb->pc == addr && tb->cs_base == cs_base &&
> >+ tb->flags == flags)) {
>
> This comparison is wrong. It will incorrectly reject a TB for i386 guest
> when CS_BASE != 0. You really want
>
> tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(addr)]);
> if (tb) {
> cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
> if (tb->pc == pc && tb->cs_base == cs_base && tb->flags == flags) {
> return tb->tc_ptr;
> }
> }
> return tcg_ctx.code_gen_epilogue;
wrt the comparison, the only change I notice in your suggested change is
tb->pc == pc
instead of
tb->pc == addr
, which seems innocuous to me (since tb->pc == addr).
I fail to see how this relates to your "CS_BASE != 0" comment.
What am I missing?
E.
