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[PULL 3/4] accel/tcg: Fix jump cache set in cpu_exec_loop
From: |
Richard Henderson |
Subject: |
[PULL 3/4] accel/tcg: Fix jump cache set in cpu_exec_loop |
Date: |
Tue, 4 Apr 2023 08:52:19 -0700 |
Assign pc and use store_release to assign tb.
Fixes: 2dd5b7a1b91 ("accel/tcg: Move jmp-cache `CF_PCREL` checks to caller")
Reported-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
accel/tcg/cpu-exec.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index c815f2dbfd..8370c92c05 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -257,7 +257,7 @@ static inline TranslationBlock *tb_lookup(CPUState *cpu,
target_ulong pc,
if (cflags & CF_PCREL) {
/* Use acquire to ensure current load of pc from jc. */
- tb = qatomic_load_acquire(&jc->array[hash].tb);
+ tb = qatomic_load_acquire(&jc->array[hash].tb);
if (likely(tb &&
jc->array[hash].pc == pc &&
@@ -272,7 +272,7 @@ static inline TranslationBlock *tb_lookup(CPUState *cpu,
target_ulong pc,
return NULL;
}
jc->array[hash].pc = pc;
- /* Use store_release on tb to ensure pc is written first. */
+ /* Ensure pc is written first. */
qatomic_store_release(&jc->array[hash].tb, tb);
} else {
/* Use rcu_read to ensure current load of pc from *tb. */
@@ -971,18 +971,27 @@ cpu_exec_loop(CPUState *cpu, SyncClocks *sc)
tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
if (tb == NULL) {
+ CPUJumpCache *jc;
uint32_t h;
mmap_lock();
tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
mmap_unlock();
+
/*
* We add the TB in the virtual pc hash table
* for the fast lookup
*/
h = tb_jmp_cache_hash_func(pc);
- /* Use the pc value already stored in tb->pc. */
- qatomic_set(&cpu->tb_jmp_cache->array[h].tb, tb);
+ jc = cpu->tb_jmp_cache;
+ if (cflags & CF_PCREL) {
+ jc->array[h].pc = pc;
+ /* Ensure pc is written first. */
+ qatomic_store_release(&jc->array[h].tb, tb);
+ } else {
+ /* Use the pc value already stored in tb->pc. */
+ qatomic_set(&jc->array[h].tb, tb);
+ }
}
#ifndef CONFIG_USER_ONLY
--
2.34.1