Re: [PATCH 10/37] accel/tcg: Use cpu_ld*_code_mmu in translator.c

[Philippe Mathieu-Daudé]

On 13/3/25 10:54, Philippe Mathieu-Daudé wrote:

Hi Richard,

On 13/3/25 04:44, Richard Henderson wrote:

Cache the mmu index in DisasContextBase.
Perform the read on host endianness, which lets us
share code with the translator_ld fast path.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
  include/exec/translator.h |  1 +
  accel/tcg/translator.c    | 57 ++++++++++++++++++---------------------
  2 files changed, 27 insertions(+), 31 deletions(-)

diff --git a/include/exec/translator.h b/include/exec/translator.h
index d70942a10f..205dd85bba 100644
--- a/include/exec/translator.h
+++ b/include/exec/translator.h
@@ -73,6 +73,7 @@ struct DisasContextBase {
      int max_insns;
      bool plugin_enabled;
      bool fake_insn;
+    uint8_t code_mmuidx;
      struct TCGOp *insn_start;
      void *host_addr[2];
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 0260fb1915..64fa069b51 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -11,10 +11,9 @@
  #include "qemu/log.h"
  #include "qemu/error-report.h"
  #include "exec/exec-all.h"
+#include "exec/cpu-ldst-common.h"
  #include "exec/translator.h"
-#include "exec/cpu_ldst.h"
  #include "exec/plugin-gen.h"
-#include "exec/cpu_ldst.h"
  #include "exec/tswap.h"
  #include "tcg/tcg-op-common.h"
  #include "internal-target.h"

@@ -142,6 +141,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,

      db->host_addr[1] = NULL;
      db->record_start = 0;
      db->record_len = 0;
+    db->code_mmuidx = cpu_mmu_index(cpu, true);
      ops->init_disas_context(db, cpu);
      tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */

@@ -457,55 +457,50 @@ bool translator_st(const DisasContextBase *db, void *dest,   uint8_t translator_ldub(CPUArchState *env, DisasContextBase *db, vaddr pc)

  {
-    uint8_t raw;
+    uint8_t val;
-    if (!translator_ld(env, db, &raw, pc, sizeof(raw))) {
-        raw = cpu_ldub_code(env, pc);
-        record_save(db, pc, &raw, sizeof(raw));
+    if (!translator_ld(env, db, &val, pc, sizeof(val))) {
+        MemOpIdx oi = make_memop_idx(MO_UB, db->code_mmuidx);
+        val = cpu_ldb_code_mmu(env, pc, oi, 0);
+        record_save(db, pc, &val, sizeof(val));
      }
-    return raw;
+    return val;
  }

  uint16_t translator_lduw(CPUArchState *env, DisasContextBase *db, vaddr pc)

  {
-    uint16_t raw, tgt;
+    uint16_t val;
-    if (translator_ld(env, db, &raw, pc, sizeof(raw))) {
-        tgt = tswap16(raw);
-    } else {
-        tgt = cpu_lduw_code(env, pc);
-        raw = tswap16(tgt);
-        record_save(db, pc, &raw, sizeof(raw));
+    if (!translator_ld(env, db, &val, pc, sizeof(val))) {
+        MemOpIdx oi = make_memop_idx(MO_UW, db->code_mmuidx);

Could we pass MO_TE rather than calling tswap()?

Answer to that is in the next patch ;)

+        val = cpu_ldw_code_mmu(env, pc, oi, 0);
+        record_save(db, pc, &val, sizeof(val));

So recorded bytes are in host endianness, is it still OK w.r.t.
translator_st() use?

      }
-    return tgt;
+    return tswap16(val);
  }