1 files changed, 40 insertions, 42 deletions

diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 1a6a5448c8..e7abcd86c1 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -14,28 +14,23 @@
 #include "exec/translator.h"
 #include "exec/plugin-gen.h"
 #include "tcg/tcg-op-common.h"
-#include "internal.h"
+#include "internal-target.h"
 
-static void gen_io_start(void)
+static void set_can_do_io(DisasContextBase *db, bool val)
 {
-    tcg_gen_st_i32(tcg_constant_i32(1), 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;
+
+        QEMU_BUILD_BUG_ON(sizeof_field(CPUState, neg.can_do_io) != 1);
+        tcg_gen_st8_i32(tcg_constant_i32(val), tcg_env,
+                        offsetof(ArchCPU, parent_obj.neg.can_do_io) -
+                        offsetof(ArchCPU, env));
+    }
 }
 
 bool translator_io_start(DisasContextBase *db)
 {
-    uint32_t cflags = tb_cflags(db->tb);
-
-    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;
-    }
-
-    gen_io_start();
+    set_can_do_io(db, true);
 
     /*
      * Ensure that this instruction will be the last in the TB.
@@ -47,14 +42,17 @@ bool translator_io_start(DisasContextBase *db)
     return true;
 }
 
-static TCGOp *gen_tb_start(uint32_t cflags)
+static TCGOp *gen_tb_start(DisasContextBase *db, uint32_t cflags)
 {
-    TCGv_i32 count = tcg_temp_new_i32();
+    TCGv_i32 count = NULL;
     TCGOp *icount_start_insn = NULL;
 
-    tcg_gen_ld_i32(count, cpu_env,
-                   offsetof(ArchCPU, neg.icount_decr.u32) -
-                   offsetof(ArchCPU, env));
+    if ((cflags & CF_USE_ICOUNT) || !(cflags & CF_NOIRQ)) {
+        count = tcg_temp_new_i32();
+        tcg_gen_ld_i32(count, tcg_env,
+                       offsetof(ArchCPU, parent_obj.neg.icount_decr.u32)
+                       - offsetof(ArchCPU, env));
+    }
 
     if (cflags & CF_USE_ICOUNT) {
         /*
@@ -81,21 +79,18 @@ static TCGOp *gen_tb_start(uint32_t cflags)
     }
 
     if (cflags & CF_USE_ICOUNT) {
-        tcg_gen_st16_i32(count, cpu_env,
-                         offsetof(ArchCPU, neg.icount_decr.u16.low) -
-                         offsetof(ArchCPU, env));
-        /*
-         * cpu->can_do_io is cleared automatically here at the beginning of
-         * each translation block.  The cost is minimal and only paid for
-         * -icount, plus it would be very easy to forget doing it in the
-         * translator. Doing it here means we don't need a gen_io_end() to
-         * go with gen_io_start().
-         */
-        tcg_gen_st_i32(tcg_constant_i32(0), cpu_env,
-                       offsetof(ArchCPU, parent_obj.can_do_io) -
-                       offsetof(ArchCPU, env));
+        tcg_gen_st16_i32(count, tcg_env,
+                         offsetof(ArchCPU, parent_obj.neg.icount_decr.u16.low)
+                         - offsetof(ArchCPU, env));
     }
 
+    /*
+     * cpu->neg.can_do_io is set automatically here at the beginning of
+     * each translation block.  The cost is minimal, plus it would be
+     * very easy to forget doing it in the translator.
+     */
+    set_can_do_io(db, db->max_insns == 1 && (cflags & CF_LAST_IO));
+
     return icount_start_insn;
 }
 
@@ -144,6 +139,7 @@ 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;
 
@@ -151,11 +147,17 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
 
     /* Start translating.  */
-    icount_start_insn = gen_tb_start(cflags);
+    icount_start_insn = gen_tb_start(db, cflags);
     ops->tb_start(db, cpu);
     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
 
-    plugin_enabled = plugin_gen_tb_start(cpu, db, cflags & CF_MEMI_ONLY);
+    if (cflags & CF_MEMI_ONLY) {
+        /* We should only see CF_MEMI_ONLY for io_recompile. */
+        assert(cflags & CF_LAST_IO);
+        plugin_enabled = plugin_gen_tb_start(cpu, db, true);
+    } else {
+        plugin_enabled = plugin_gen_tb_start(cpu, db, false);
+    }
 
     while (true) {
         *max_insns = ++db->num_insns;
@@ -172,13 +174,9 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
            the next instruction.  */
         if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
             /* Accept I/O on the last instruction.  */
-            gen_io_start();
-            ops->translate_insn(db, cpu);
-        } else {
-            /* we should only see CF_MEMI_ONLY for io_recompile */
-            tcg_debug_assert(!(cflags & CF_MEMI_ONLY));
-            ops->translate_insn(db, cpu);
+            set_can_do_io(db, true);
         }
+        ops->translate_insn(db, cpu);
 
         /*
          * We can't instrument after instructions that change control