tcg: make tcg_allowed global

Change the tcg_enabled() and make sure user build still enable tcg
even x86 softmmu disable tcg.
Signed-off-by: NYang Zhong <yang.zhong@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

accel/tcg/cpu-exec-common.c

@@ -23,6 +23,8 @@
 #include "exec/exec-all.h"
 #include "exec/memory-internal.h"
 
+bool tcg_allowed;
+
 /* exit the current TB, but without causing any exception to be raised */
 void cpu_loop_exit_noexc(CPUState *cpu)
 {

accel/tcg/tcg-all.c

@@ -33,7 +33,6 @@
 #include "qemu/main-loop.h"
 
 unsigned long tcg_tb_size;
-static bool tcg_allowed = true;
 
 #ifndef CONFIG_USER_ONLY
 /* mask must never be zero, except for A20 change call */

accel/tcg/translate-all.c

@@ -784,6 +784,7 @@ static void tb_htable_init(void)
    size. */
 void tcg_exec_init(unsigned long tb_size)
 {
+    tcg_allowed = true;
     cpu_gen_init();
     page_init();
     tb_htable_init();
@@ -795,11 +796,6 @@ void tcg_exec_init(unsigned long tb_size)
 #endif
 }
 
-bool tcg_enabled(void)
-{
-    return tcg_ctx.code_gen_buffer != NULL;
-}
-
 /*
  * Allocate a new translation block. Flush the translation buffer if
  * too many translation blocks or too much generated code.

include/qemu-common.h

@@ -76,8 +76,13 @@ int qemu_openpty_raw(int *aslave, char *pty_name);
     sendto(sockfd, buf, len, flags, destaddr, addrlen)
 #endif
 
+extern bool tcg_allowed;
 void tcg_exec_init(unsigned long tb_size);
-bool tcg_enabled(void);
+#ifdef CONFIG_TCG
+#define tcg_enabled() (tcg_allowed)
+#else
+#define tcg_enabled() 0
+#endif
 
 void cpu_exec_init_all(void);
 void cpu_exec_step_atomic(CPUState *cpu);