On 07/16/2017 10:03 AM, Emilio G. Cota wrote:
@@ -1073,13 +1073,17 @@ void tb_phys_invalidate(TranslationBlock *tb,
tb_page_addr_t page_addr)
assert_tb_locked();
- atomic_set(&tb->invalid, true);
-
/* remove the TB from the hash list */
phys_pc = tb->page_addr[0] + (tb->pc & ~TARGET_PAGE_MASK);
h = tb_hash_func(phys_pc, tb->pc, tb->flags, tb->trace_vcpu_dstate);
qht_remove(&tcg_ctx.tb_ctx.htable, tb, h);
+ /*
+ * Mark the TB as invalid *after* it's been removed from tb_hash, which
+ * eliminates the need to check this bit on lookups.
+ */
+ tb->invalid = true;
I believe you need atomic_store_release here. Previously we were relying on
the lock acquisition in qht_remove to provide the required memory barrier.
We definitely need to make sure this reaches memory before we zap the TB in the
CPU_FOREACH loop.
r~
