accel/tcg: Reduce CF_COUNT_MASK to match TCG_MAX_INSNS

The space reserved for CF_COUNT_MASK was overly large. Reduce to free up cflags bits and eliminate an extra test. Tested-by: Mark Cave-Ayland <[email protected]> Signed-off-by: Richard Henderson <[email protected]> Reviewed-by: Alex Bennée <[email protected]> Reviewed-by: Peter Maydell <[email protected]> Message-Id: <[email protected]>
sekmet · Jul 21, 2021 · 78ff82b · 78ff82b
1 parent f3e182b
commit 78ff82b
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
@@ -1428,11 +1428,10 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
 
     max_insns = cflags & CF_COUNT_MASK;
     if (max_insns == 0) {
-        max_insns = CF_COUNT_MASK;
-    }
-    if (max_insns > TCG_MAX_INSNS) {
         max_insns = TCG_MAX_INSNS;
     }
+    QEMU_BUILD_BUG_ON(CF_COUNT_MASK + 1 != TCG_MAX_INSNS);
+
     if (cpu->singlestep_enabled || singlestep) {
         max_insns = 1;
     }

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
@@ -492,7 +492,9 @@ struct TranslationBlock {
     target_ulong cs_base; /* CS base for this block */
     uint32_t flags; /* flags defining in which context the code was generated */
     uint32_t cflags;    /* compile flags */
-#define CF_COUNT_MASK  0x00007fff
+
+/* Note that TCG_MAX_INSNS is 512; we validate this match elsewhere. */
+#define CF_COUNT_MASK  0x000001ff
 #define CF_LAST_IO     0x00008000 /* Last insn may be an IO access.  */
 #define CF_MEMI_ONLY   0x00010000 /* Only instrument memory ops */
 #define CF_USE_ICOUNT  0x00020000