| Message ID | 1468354426-837-4-git-send-email-sergey.fedorov@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Sergey Fedorov <sergey.fedorov@linaro.org> writes: > From: Sergey Fedorov <serge.fdrv@gmail.com> > > 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 <serge.fdrv@gmail.com> > Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org> > [AJB: fixed missing atomic set, tweak title] > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > [Sergey Fedorov: removed explicit memory barriers; > memset() on 'tb_jmp_cache' replaced with a loop on atomic_set(); > tweaked commit title and message] > Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Not sure it counts as it's already had my s-o-b when I last had the tree but there you go ;-) > > --- > 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 757f63b08b6b..d6178eab71d4 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); > } > } -- Alex Bennée
diff --git a/cpu-exec.c b/cpu-exec.c index 757f63b08b6b..d6178eab71d4 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); } }