[Qemu-devel] [RFC PATCH v6 15/32] cpu-exec: allow temporary disabling icount

[Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>]

This patch is required for deterministic replay to generate an exception
by trying executing an instruction without changing icount.
It adds new flag to TB for disabling icount while translating it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 cpu-exec.c              |    6 +++---
 include/exec/exec-all.h |    1 +
 translate-all.c         |    2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/cpu-exec.c b/cpu-exec.c
index 0dff591..681d636 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -200,7 +200,7 @@ static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
 /* Execute the code without caching the generated code. An interpreter
    could be used if available. */
 static void cpu_exec_nocache(CPUArchState *env, int max_cycles,
-                             TranslationBlock *orig_tb)
+                             TranslationBlock *orig_tb, bool ignore_icount)
 {
     CPUState *cpu = ENV_GET_CPU(env);
     TranslationBlock *tb;
@@ -216,7 +216,7 @@ static void cpu_exec_nocache(CPUArchState *env, int max_cycles,
     /* tb_gen_code can flush our orig_tb, invalidate it now */
     tb_phys_invalidate(orig_tb, -1);
     tb = tb_gen_code(cpu, pc, cs_base, flags,
-                     max_cycles);
+                     max_cycles | (ignore_icount ? CF_IGNORE_ICOUNT : 0));
     cpu->current_tb = tb;
     /* execute the generated code */
     trace_exec_tb_nocache(tb, tb->pc);
@@ -525,7 +525,7 @@ int cpu_exec(CPUArchState *env)
                         } else {
                             if (insns_left > 0) {
                                 /* Execute remaining instructions.  */
-                                cpu_exec_nocache(env, insns_left, tb);
+                                cpu_exec_nocache(env, insns_left, tb, false);
                                 align_clocks(&sc, cpu);
                             }
                             cpu->exception_index = EXCP_INTERRUPT;
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 14d1a1b..12adf02 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -147,6 +147,7 @@ struct TranslationBlock {
 #define CF_COUNT_MASK  0x7fff
 #define CF_LAST_IO     0x8000 /* Last insn may be an IO access.  */
 #define CF_USE_ICOUNT  0x10000
+#define CF_IGNORE_ICOUNT 0x20000 /* Do not generate icount code */
 
     void *tc_ptr;    /* pointer to the translated code */
     /* next matching tb for physical address. */
diff --git a/translate-all.c b/translate-all.c
index c256d58..21a78a4 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1047,7 +1047,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     int code_gen_size;
 
     phys_pc = get_page_addr_code(env, pc);
-    if (use_icount) {
+    if (use_icount && !(cflags & CF_IGNORE_ICOUNT)) {
         cflags |= CF_USE_ICOUNT;
     }
     tb = tb_alloc(pc);