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[Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup |
Date: |
Tue, 19 Jul 2016 10:32:16 +0200 |
When invalidating a translation block, set an invalid flag into the
TranslationBlock structure first. It is also necessary to check whether
the target TB is still valid after acquiring 'tb_lock' but before calling
tb_add_jump() since TB lookup is to be performed out of 'tb_lock' in
future. Note that we don't have to check 'last_tb'; an already invalidated
TB will not be executed anyway and it is thus safe to patch it.
Suggested-by: Sergey Fedorov <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpu-exec.c | 5 +++--
include/exec/exec-all.h | 2 ++
translate-all.c | 3 +++
3 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 877ff8e..cdaab1d 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -241,7 +241,8 @@ static bool tb_cmp(const void *p, const void *d)
if (tb->pc == desc->pc &&
tb->page_addr[0] == desc->phys_page1 &&
tb->cs_base == desc->cs_base &&
- tb->flags == desc->flags) {
+ tb->flags == desc->flags &&
+ !atomic_read(&tb->invalid)) {
/* check next page if needed */
if (tb->page_addr[1] == -1) {
return true;
@@ -352,7 +353,7 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
/* Check if translation buffer has been flushed */
if (cpu->tb_flushed) {
cpu->tb_flushed = false;
- } else {
+ } else if (!tb->invalid) {
tb_add_jump(last_tb, tb_exit, tb);
}
}
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index acda7b6..bc0bcc5 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -213,6 +213,8 @@ struct TranslationBlock {
#define CF_USE_ICOUNT 0x20000
#define CF_IGNORE_ICOUNT 0x40000 /* Do not generate icount code */
+ uint16_t invalid;
+
void *tc_ptr; /* pointer to the translated code */
uint8_t *tc_search; /* pointer to search data */
/* original tb when cflags has CF_NOCACHE */
diff --git a/translate-all.c b/translate-all.c
index 788fed1..eaa1232 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -773,6 +773,7 @@ static TranslationBlock *tb_alloc(target_ulong pc)
tb = &tcg_ctx.tb_ctx.tbs[tcg_ctx.tb_ctx.nb_tbs++];
tb->pc = pc;
tb->cflags = 0;
+ tb->invalid = false;
return tb;
}
@@ -991,6 +992,8 @@ void tb_phys_invalidate(TranslationBlock *tb,
tb_page_addr_t page_addr)
uint32_t h;
tb_page_addr_t phys_pc;
+ 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);
--
2.7.4
- [Qemu-devel] [PATCH v5 00/10] Reduce lock contention on TCG hot-path, Paolo Bonzini, 2016/07/19
- [Qemu-devel] [PATCH 02/10] tcg: Pass last_tb by value to tb_find_fast(), Paolo Bonzini, 2016/07/19
- [Qemu-devel] [PATCH 01/10] util/qht: Document memory ordering assumptions, Paolo Bonzini, 2016/07/19
- [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup, Sergey Fedorov, 2016/07/19
- Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup, Paolo Bonzini, 2016/07/19
- Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup, Sergey Fedorov, 2016/07/21
- Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup, Paolo Bonzini, 2016/07/21
- Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup, Paolo Bonzini, 2016/07/21
- Re: [Qemu-devel] [PATCH 05/10] tcg: Prepare TB invalidation for lockless TB lookup, Sergey Fedorov, 2016/07/21
[Qemu-devel] [PATCH 03/10] tcg: Prepare safe tb_jmp_cache lookup out of tb_lock, Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 04/10] tcg: Prepare safe access to tb_flushed out of tb_lock, Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 06/10] tcg: set up tb->page_addr before insertion, Paolo Bonzini, 2016/07/19
[Qemu-devel] [PATCH 08/10] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Paolo Bonzini, 2016/07/19