accel/tcg: Add fast path for translator_ld*

Cache the translation from guest to host address, so we may
use direct loads when we hit on the primary translation page.

Look up the second translation page only once, during translation.
This obviates another lookup of the second page within tb_gen_code
after translation.

Fixes a bug in that plugin_insn_append should be passed the bytes
in the original memory order, not bswapped by pieces.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 8 insertions, 15 deletions

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 587886aa4e..f5e8592d4a 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1385,8 +1385,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
 {
     CPUArchState *env = cpu->env_ptr;
     TranslationBlock *tb, *existing_tb;
-    tb_page_addr_t phys_pc, phys_page2;
-    target_ulong virt_page2;
+    tb_page_addr_t phys_pc;
     tcg_insn_unit *gen_code_buf;
     int gen_code_size, search_size, max_insns;
 #ifdef CONFIG_PROFILER
@@ -1429,6 +1428,8 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     tb->flags = flags;
     tb->cflags = cflags;
     tb->trace_vcpu_dstate = *cpu->trace_dstate;
+    tb->page_addr[0] = phys_pc;
+    tb->page_addr[1] = -1;
     tcg_ctx->tb_cflags = cflags;
  tb_overflow:
 
@@ -1622,13 +1623,11 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     }
 
     /*
-     * If the TB is not associated with a physical RAM page then
-     * it must be a temporary one-insn TB, and we have nothing to do
-     * except fill in the page_addr[] fields. Return early before
-     * attempting to link to other TBs or add to the lookup table.
+     * If the TB is not associated with a physical RAM page then it must be
+     * a temporary one-insn TB, and we have nothing left to do. Return early
+     * before attempting to link to other TBs or add to the lookup table.
      */
-    if (phys_pc == -1) {
-        tb->page_addr[0] = tb->page_addr[1] = -1;
+    if (tb->page_addr[0] == -1) {
         return tb;
     }
 
@@ -1639,17 +1638,11 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
      */
     tcg_tb_insert(tb);
 
-    /* check next page if needed */
-    virt_page2 = (pc + tb->size - 1) & TARGET_PAGE_MASK;
-    phys_page2 = -1;
-    if ((pc & TARGET_PAGE_MASK) != virt_page2) {
-        phys_page2 = get_page_addr_code(env, virt_page2);
-    }
     /*
      * No explicit memory barrier is required -- tb_link_page() makes the
      * TB visible in a consistent state.
      */
-    existing_tb = tb_link_page(tb, phys_pc, phys_page2);
+    existing_tb = tb_link_page(tb, tb->page_addr[0], tb->page_addr[1]);
     /* if the TB already exists, discard what we just translated */
     if (unlikely(existing_tb != tb)) {
         uintptr_t orig_aligned = (uintptr_t)gen_code_buf;