[Qemu-devel] [RFC PATCH 05/10] exec: small adjustments for TCG separation

[Paolo Bonzini]

Add stubs for cpu_restore_state and tlb_fill, which should respectively
have no effect and never be used outside TCG mode.

Add assertions that TCG is enabled around code that calls to TCG from
exec.c, so that the compiler can remove the entire functions as dead
(the proper way to do this should be to move them to cpu-exec.c
instead).

Signed-off-by: Paolo Bonzini <address@hidden>
---
 cpu-exec.c |  2 ++
 exec-all.h | 20 ++++++++++++++++++--
 exec.c     | 55 ++++++++++++++++++++++++++++++++++---------------------
 3 file modificati, 54 inserzioni(+), 23 rimozioni(-)

diff --git a/cpu-exec.c b/cpu-exec.c
index 134b3c4..b047b6c 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -189,6 +189,8 @@ int cpu_exec(CPUArchState *env)
     uint8_t *tc_ptr;
     tcg_target_ulong next_tb;
 
+    assert(tcg_enabled());
+
     if (env->halted) {
         if (!cpu_has_work(env)) {
             return EXCP_HALTED;
diff --git a/exec-all.h b/exec-all.h
index cecafa1..4c61ed1 100644
--- a/exec-all.h
+++ b/exec-all.h
@@ -84,8 +84,6 @@ void restore_state_to_opc(CPUArchState *env, struct 
TranslationBlock *tb,
 void cpu_gen_init(void);
 int cpu_gen_code(CPUArchState *env, struct TranslationBlock *tb,
                  int *gen_code_size_ptr);
-void cpu_restore_state(struct TranslationBlock *tb,
-                       CPUArchState *env, uintptr_t searched_pc);
 void QEMU_NORETURN cpu_resume_from_signal(CPUArchState *env1, void *puc);
 void QEMU_NORETURN cpu_io_recompile(CPUArchState *env, uintptr_t retaddr);
 TranslationBlock *tb_gen_code(CPUArchState *env, 
@@ -282,6 +280,16 @@ static inline void tb_add_jump(TranslationBlock *tb, int n,
 
 TranslationBlock *tb_find_pc(uintptr_t pc_ptr);
 
+#ifdef CONFIG_TCG
+void cpu_restore_state(struct TranslationBlock *tb,
+                       CPUArchState *env, uintptr_t searched_pc);
+#else
+static inline void cpu_restore_state(struct TranslationBlock *tb,
+                                     CPUArchState *env, uintptr_t searched_pc)
+{
+}
+#endif
+
 #include "qemu-lock.h"
 
 extern spinlock_t tb_lock;
@@ -316,8 +324,16 @@ uint64_t io_mem_read(struct MemoryRegion *mr, 
target_phys_addr_t addr,
 void io_mem_write(struct MemoryRegion *mr, target_phys_addr_t addr,
                   uint64_t value, unsigned size);
 
+#ifdef CONFIG_TCG
 void tlb_fill(CPUArchState *env1, target_ulong addr, int is_write, int mmu_idx,
               uintptr_t retaddr);
+#else
+static inline void tlb_fill(CPUArchState *env1, target_ulong addr,
+                            int is_write, int mmu_idx, uintptr_t retaddr)
+{
+    abort();
+}
+#endif
 
 #include "softmmu_defs.h"
 
diff --git a/exec.c b/exec.c
index 1270d78..3e77de2 100644
--- a/exec.c
+++ b/exec.c
@@ -108,6 +108,8 @@ static unsigned long code_gen_buffer_size;
 static unsigned long code_gen_buffer_max_size;
 static uint8_t *code_gen_ptr;
 
+CPUInterruptHandler cpu_interrupt_handler;
+
 #if !defined(CONFIG_USER_ONLY)
 int phys_ram_fd;
 static int in_migration;
@@ -610,24 +612,6 @@ static void code_gen_alloc(unsigned long tb_size)
     tbs = g_malloc(code_gen_max_blocks * sizeof(TranslationBlock));
 }
 
-/* Must be called before using the QEMU cpus. 'tb_size' is the size
-   (in bytes) allocated to the translation buffer. Zero means default
-   size. */
-void tcg_exec_init(unsigned long tb_size)
-{
-    tcg_allowed = 1;
-    cpu_gen_init();
-    code_gen_alloc(tb_size);
-    code_gen_ptr = code_gen_buffer;
-    tcg_register_jit(code_gen_buffer, code_gen_buffer_size);
-    page_init();
-#if !defined(CONFIG_USER_ONLY) || !defined(CONFIG_USE_GUEST_BASE)
-    /* There's no guest base to take into account, so go ahead and
-       initialize the prologue now.  */
-    tcg_prologue_init(&tcg_ctx);
-#endif
-}
-
 void cpu_exec_init_all(void)
 {
 #if !defined(CONFIG_USER_ONLY)
@@ -1032,6 +1016,8 @@ TranslationBlock *tb_gen_code(CPUArchState *env,
     target_ulong virt_page2;
     int code_gen_size;
 
+    assert(tcg_enabled());
+
     phys_pc = get_page_addr_code(env, pc);
     tb = tb_alloc(pc);
     if (!tb) {
@@ -1707,9 +1693,6 @@ static void tcg_handle_interrupt(CPUArchState *env, int 
mask)
         cpu_unlink_tb(env);
     }
 }
-
-CPUInterruptHandler cpu_interrupt_handler = tcg_handle_interrupt;
-
 #else /* CONFIG_USER_ONLY */
 
 void cpu_interrupt(CPUArchState *env, int mask)
@@ -2934,6 +2917,8 @@ static void check_watchpoint(int offset, int len_mask, 
int flags)
     CPUWatchpoint *wp;
     int cpu_flags;
 
+    assert(tcg_enabled());
+
     if (env->watchpoint_hit) {
         /* We re-entered the check after replacing the TB. Now raise
          * the debug interrupt so that is will trigger after the
@@ -4112,6 +4097,8 @@ void cpu_io_recompile(CPUArchState *env, uintptr_t 
retaddr)
     target_ulong pc, cs_base;
     uint64_t flags;
 
+    assert(tcg_enabled());
+
     tb = tb_find_pc(retaddr);
     if (!tb) {
         cpu_abort(env, "cpu_io_recompile: could not find TB for pc=%p", 
@@ -4243,3 +4230,29 @@ bool cpu_physical_memory_is_io(target_phys_addr_t 
phys_addr)
              memory_region_is_romd(section->mr));
 }
 #endif
+
+/* Must be called before using the QEMU cpus. 'tb_size' is the size
+   (in bytes) allocated to the translation buffer. Zero means default
+   size. */
+void tcg_exec_init(unsigned long tb_size)
+{
+#ifndef CONFIG_TCG
+    /* We cannot yet use tcg_enabled() here, it is set below.  */
+    return;
+#endif
+
+    tcg_allowed = 1;
+#ifndef CONFIG_USER_ONLY
+    cpu_interrupt_handler = tcg_handle_interrupt;
+#endif
+    cpu_gen_init();
+    code_gen_alloc(tb_size);
+    code_gen_ptr = code_gen_buffer;
+    tcg_register_jit(code_gen_buffer, code_gen_buffer_size);
+    page_init();
+#if !defined(CONFIG_USER_ONLY) || !defined(CONFIG_USE_GUEST_BASE)
+    /* There's no guest base to take into account, so go ahead and
+       initialize the prologue now.  */
+    tcg_prologue_init(&tcg_ctx);
+#endif
+}
-- 
1.7.12