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[PATCH 3/6: 2/2] accel/tcg: Track current value of can_do_io in the TB
From: |
Philippe Mathieu-Daudé |
Subject: |
[PATCH 3/6: 2/2] accel/tcg: Track current value of can_do_io in the TB |
Date: |
Fri, 15 Sep 2023 11:41:09 +0200 |
From: Richard Henderson <richard.henderson@linaro.org>
Simplify translator_io_start by recording the current
known value of can_do_io within DisasContextBase.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20230914174436.1597356-4-richard.henderson@linaro.org>
[PMD: Split patch in 2, extracting set_can_do_io() first]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
include/exec/translator.h | 2 ++
accel/tcg/translator.c | 14 +++++++-------
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/include/exec/translator.h b/include/exec/translator.h
index 4e17c4f401..9d9e980819 100644
--- a/include/exec/translator.h
+++ b/include/exec/translator.h
@@ -72,6 +72,7 @@ typedef enum DisasJumpType {
* @num_insns: Number of translated instructions (including current).
* @max_insns: Maximum number of instructions to be translated in this TB.
* @singlestep_enabled: "Hardware" single stepping enabled.
+ * @saved_can_do_io: Known value of cpu->neg.can_do_io, or -1 for unknown.
*
* Architecture-agnostic disassembly context.
*/
@@ -83,6 +84,7 @@ typedef struct DisasContextBase {
int num_insns;
int max_insns;
bool singlestep_enabled;
+ int8_t saved_can_do_io;
void *host_addr[2];
} DisasContextBase;
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index cebf0a84cc..850d82e26f 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -18,9 +18,12 @@
static void set_can_do_io(DisasContextBase *db, bool val)
{
- tcg_gen_st_i32(tcg_constant_i32(val), cpu_env,
- offsetof(ArchCPU, parent_obj.can_do_io) -
- offsetof(ArchCPU, env));
+ if (db->saved_can_do_io != val) {
+ db->saved_can_do_io = val;
+ tcg_gen_st_i32(tcg_constant_i32(val), cpu_env,
+ offsetof(ArchCPU, parent_obj.can_do_io) -
+ offsetof(ArchCPU, env));
+ }
}
bool translator_io_start(DisasContextBase *db)
@@ -30,10 +33,6 @@ bool translator_io_start(DisasContextBase *db)
if (!(cflags & CF_USE_ICOUNT)) {
return false;
}
- if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
- /* Already started in translator_loop. */
- return true;
- }
set_can_do_io(db, true);
@@ -144,6 +143,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb,
int *max_insns,
db->num_insns = 0;
db->max_insns = *max_insns;
db->singlestep_enabled = cflags & CF_SINGLE_STEP;
+ db->saved_can_do_io = -1;
db->host_addr[0] = host_pc;
db->host_addr[1] = NULL;
--
2.41.0