Patchwork [05/18] backdoor: [i386] Decode backdoor instructions

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Submitter =?utf-8?Q?Llu=C3=ADs?=
Date Oct. 19, 2010, 7:14 p.m.
Message ID <495cba98dfc4cc5c40cc1a572327729d8926c596.1287772676.git.vilanova@ac.upc.edu>
Download mbox | patch
Permalink /patch/68958/
State New
Headers show

Comments

=?utf-8?Q?Llu=C3=ADs?= - Oct. 19, 2010, 7:14 p.m.
Decode backdoor instructions following "backdoor/guest.h" and call the
user-defined backdoor helpers.

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
 target-i386/translate.c |   30 ++++++++++++++++++++++++++++++
 1 files changed, 30 insertions(+), 0 deletions(-)

Patch

diff --git a/target-i386/translate.c b/target-i386/translate.c
index 7b6e3c2..b54a823 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -4105,6 +4105,31 @@  static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
     x86_64_hregs = 0;
 #endif
     s->rip_offset = 0; /* for relative ip address */
+
+#if defined(CONFIG_BACKDOOR)
+    if (ldub_code(s->pc) == 0x0f &&  ldub_code(s->pc + 1) == 0x04) {
+        uint8_t type = ldub_code(s->pc + 2);
+        TCGv_i32 cmd;
+        /* TODO: should break TB, but gen_eob generates an infinite loop */
+        switch (type) {
+        case 0x00:                      /* i8 */
+            cmd = tcg_const_i32((uint32_t)ldub_code(s->pc + 3));
+            gen_helper_backdoor_i8(cmd);
+            break;
+        case 0x01:                      /* i8 v */
+            cmd = tcg_const_i32(ldub_code(s->pc + 3));
+            gen_helper_backdoor_i8_v(cmd, cpu_regs[R_EAX]);
+            break;
+        default:
+            goto illegal_op;
+        }
+        s->pc += 4;
+        gen_jmp_im(s->pc);
+        gen_eob(s);
+        goto backdoor_done;
+    }
+#endif
+
  next_byte:
     b = ldub_code(s->pc);
     s->pc++;
@@ -7636,6 +7661,11 @@  static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
     default:
         goto illegal_op;
     }
+
+#if defined(CONFIG_BACKDOOR)
+backdoor_done:
+#endif
+
     /* lock generation */
     if (s->prefix & PREFIX_LOCK)
         gen_helper_unlock();