From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48557) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bO7OE-0002TZ-9P for qemu-devel@nongnu.org; Fri, 15 Jul 2016 13:59:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bO7OC-0006zD-B8 for qemu-devel@nongnu.org; Fri, 15 Jul 2016 13:59:05 -0400 Received: from mail-lf0-x233.google.com ([2a00:1450:4010:c07::233]:34586) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bO7OB-0006z4-Uf for qemu-devel@nongnu.org; Fri, 15 Jul 2016 13:59:04 -0400 Received: by mail-lf0-x233.google.com with SMTP id l69so36596717lfg.1 for ; Fri, 15 Jul 2016 10:59:03 -0700 (PDT) From: Sergey Fedorov Date: Fri, 15 Jul 2016 20:58:43 +0300 Message-Id: <20160715175852.30749-4-sergey.fedorov@linaro.org> In-Reply-To: <20160715175852.30749-1-sergey.fedorov@linaro.org> References: <20160715175852.30749-1-sergey.fedorov@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v4 03/12] tcg: Prepare safe tb_jmp_cache lookup out of tb_lock List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: patches@linaro.org, Sergey Fedorov , mttcg@listserver.greensocs.com, fred.konrad@greensocs.com, a.rigo@virtualopensystems.com, cota@braap.org, bobby.prani@gmail.com, rth@twiddle.net, mark.burton@greensocs.com, pbonzini@redhat.com, jan.kiszka@siemens.com, peter.maydell@linaro.org, claudio.fontana@huawei.com, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Sergey Fedorov , Peter Crosthwaite From: Sergey Fedorov 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: Sergey Fedorov Signed-off-by: Sergey Fedorov [AJB: fixed missing atomic set, tweak title] Signed-off-by: Alex Bennée [Sergey Fedorov: removed explicit memory barriers; removed unnecessary atomic_read(); tweaked commit title and message] Signed-off-by: Sergey Fedorov Reviewed-by: Alex Bennée --- Changes in v3: - explicit memory barriers removed - memset() on 'tb_jmp_cache' replaced with a loop on atomic_set() Changes in v2: - fix spelling s/con't/can't/ - add atomic_read while clearing tb_jmp_cache - add r-b tags Changes in v1 (AJB): - tweak title - fixed missing set of tb_jmp_cache --- cpu-exec.c | 4 ++-- translate-all.c | 10 +++++++--- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index 974de6aa27ee..2fd1875a7317 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -315,7 +315,7 @@ static TranslationBlock *tb_find_slow(CPUState *cpu, found: /* we add the TB in the virtual pc hash table */ - cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb; + atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb); return tb; } @@ -333,7 +333,7 @@ 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 0d47c1c0cf82..fdf520a86d68 100644 --- a/translate-all.c +++ b/translate-all.c @@ -848,7 +848,11 @@ void tb_flush(CPUState *cpu) tcg_ctx.tb_ctx.nb_tbs = 0; CPU_FOREACH(cpu) { - memset(cpu->tb_jmp_cache, 0, sizeof(cpu->tb_jmp_cache)); + int i; + + for (i = 0; i < TB_JMP_CACHE_SIZE; ++i) { + atomic_set(&cpu->tb_jmp_cache[i], NULL); + } cpu->tb_flushed = true; } @@ -1007,8 +1011,8 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr) /* 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) { - cpu->tb_jmp_cache[h] = NULL; + if (atomic_read(&cpu->tb_jmp_cache[h]) == tb) { + atomic_set(&cpu->tb_jmp_cache[h], NULL); } } -- 2.9.1