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-rw-r--r--accel/tcg/translate-all.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 464b3c3394..bbd919a393 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -2400,7 +2400,8 @@ void tb_check_watchpoint(CPUState *cpu, uintptr_t retaddr)
 }
 
 #ifndef CONFIG_USER_ONLY
-/* in deterministic execution mode, instructions doing device I/Os
+/*
+ * In deterministic execution mode, instructions doing device I/Os
  * must be at the end of the TB.
  *
  * Called by softmmu_template.h, with iothread mutex not held.
@@ -2431,19 +2432,18 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
         n = 2;
     }
 
-    /* Generate a new TB executing the I/O insn.  */
-    cpu->cflags_next_tb = curr_cflags() | CF_LAST_IO | n;
+    /*
+     * Exit the loop and potentially generate a new TB executing the
+     * just the I/O insns. We also limit instrumentation to memory
+     * operations only (which execute after completion) so we don't
+     * double instrument the instruction.
+     */
+    cpu->cflags_next_tb = curr_cflags() | CF_MEMI_ONLY | CF_LAST_IO | n;
 
     qemu_log_mask_and_addr(CPU_LOG_EXEC, tb->pc,
                            "cpu_io_recompile: rewound execution of TB to "
                            TARGET_FMT_lx "\n", tb->pc);
 
-    /* TODO: If env->pc != tb->pc (i.e. the faulting instruction was not
-     * the first in the TB) then we end up generating a whole new TB and
-     *  repeating the fault, which is horribly inefficient.
-     *  Better would be to execute just this insn uncached, or generate a
-     *  second new TB.
-     */
     cpu_loop_exit_noexc(cpu);
 }