mirror of https://gitlab.com/qemu-project/qemu
tcg: Prepare safe tb_jmp_cache lookup out of tb_lock
Ensure atomicity of CPU's 'tb_jmp_cache' access for future translation block lookup out of 'tb_lock'. Note that this patch does *not* make CPU's TLB invalidation safe if it is done from some other thread while the CPU is in its execution loop. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com> Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20160715175852.30749-4-sergey.fedorov@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@ -315,7 +315,7 @@ static TranslationBlock *tb_find_slow(CPUState *cpu,
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found:
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found:
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/* we add the TB in the virtual pc hash table */
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/* we add the TB in the virtual pc hash table */
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cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb;
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atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
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return tb;
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return tb;
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}
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}
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@ -333,7 +333,7 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
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is executed. */
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is executed. */
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cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
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cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
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tb_lock();
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tb_lock();
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tb = cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)];
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tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]);
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if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
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if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
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tb->flags != flags)) {
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tb->flags != flags)) {
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tb = tb_find_slow(cpu, pc, cs_base, flags);
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tb = tb_find_slow(cpu, pc, cs_base, flags);
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@ -851,7 +851,11 @@ void tb_flush(CPUState *cpu)
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tcg_ctx.tb_ctx.nb_tbs = 0;
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tcg_ctx.tb_ctx.nb_tbs = 0;
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CPU_FOREACH(cpu) {
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CPU_FOREACH(cpu) {
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memset(cpu->tb_jmp_cache, 0, sizeof(cpu->tb_jmp_cache));
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int i;
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for (i = 0; i < TB_JMP_CACHE_SIZE; ++i) {
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atomic_set(&cpu->tb_jmp_cache[i], NULL);
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}
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cpu->tb_flushed = true;
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cpu->tb_flushed = true;
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}
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}
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@ -1010,8 +1014,8 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)
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/* remove the TB from the hash list */
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/* remove the TB from the hash list */
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h = tb_jmp_cache_hash_func(tb->pc);
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h = tb_jmp_cache_hash_func(tb->pc);
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CPU_FOREACH(cpu) {
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CPU_FOREACH(cpu) {
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if (cpu->tb_jmp_cache[h] == tb) {
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if (atomic_read(&cpu->tb_jmp_cache[h]) == tb) {
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cpu->tb_jmp_cache[h] = NULL;
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atomic_set(&cpu->tb_jmp_cache[h], NULL);
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}
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}
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}
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}
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