target/i386: Implement CPUID_EXT_RDRAND

We now have an interface for guest visible random numbers.

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 47 insertions, 15 deletions

diff --git a/target/i386/translate.c b/target/i386/translate.c
index 77d6b73e42..03150a86e2 100644
--- a/target/i386/translate.c
+++ b/target/i386/translate.c
@@ -5332,31 +5332,63 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
     case 0x1c7: /* cmpxchg8b */
         modrm = x86_ldub_code(env, s);
         mod = (modrm >> 6) & 3;
-        if ((mod == 3) || ((modrm & 0x38) != 0x8))
-            goto illegal_op;
-#ifdef TARGET_X86_64
-        if (dflag == MO_64) {
-            if (!(s->cpuid_ext_features & CPUID_EXT_CX16))
+        switch ((modrm >> 3) & 7) {
+        case 1: /* CMPXCHG8, CMPXCHG16 */
+            if (mod == 3) {
                 goto illegal_op;
-            gen_lea_modrm(env, s, modrm);
-            if ((s->prefix & PREFIX_LOCK) && (tb_cflags(s->base.tb) & CF_PARALLEL)) {
-                gen_helper_cmpxchg16b(cpu_env, s->A0);
-            } else {
-                gen_helper_cmpxchg16b_unlocked(cpu_env, s->A0);
             }
-        } else
+#ifdef TARGET_X86_64
+            if (dflag == MO_64) {
+                if (!(s->cpuid_ext_features & CPUID_EXT_CX16)) {
+                    goto illegal_op;
+                }
+                gen_lea_modrm(env, s, modrm);
+                if ((s->prefix & PREFIX_LOCK) &&
+                    (tb_cflags(s->base.tb) & CF_PARALLEL)) {
+                    gen_helper_cmpxchg16b(cpu_env, s->A0);
+                } else {
+                    gen_helper_cmpxchg16b_unlocked(cpu_env, s->A0);
+                }
+                set_cc_op(s, CC_OP_EFLAGS);
+                break;
+            }
 #endif        
-        {
-            if (!(s->cpuid_features & CPUID_CX8))
+            if (!(s->cpuid_features & CPUID_CX8)) {
                 goto illegal_op;
+            }
             gen_lea_modrm(env, s, modrm);
-            if ((s->prefix & PREFIX_LOCK) && (tb_cflags(s->base.tb) & CF_PARALLEL)) {
+            if ((s->prefix & PREFIX_LOCK) &&
+                (tb_cflags(s->base.tb) & CF_PARALLEL)) {
                 gen_helper_cmpxchg8b(cpu_env, s->A0);
             } else {
                 gen_helper_cmpxchg8b_unlocked(cpu_env, s->A0);
             }
+            set_cc_op(s, CC_OP_EFLAGS);
+            break;
+
+        case 7: /* RDSEED */
+        case 6: /* RDRAND */
+            if (mod != 3 ||
+                (s->prefix & (PREFIX_LOCK | PREFIX_REPZ | PREFIX_REPNZ)) ||
+                !(s->cpuid_ext_features & CPUID_EXT_RDRAND)) {
+                goto illegal_op;
+            }
+            if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
+                gen_io_start();
+            }
+            gen_helper_rdrand(s->T0, cpu_env);
+            rm = (modrm & 7) | REX_B(s);
+            gen_op_mov_reg_v(s, dflag, rm, s->T0);
+            set_cc_op(s, CC_OP_EFLAGS);
+            if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
+                gen_io_end();
+                gen_jmp(s, s->pc - s->cs_base);
+            }
+            break;
+
+        default:
+            goto illegal_op;
         }
-        set_cc_op(s, CC_OP_EFLAGS);
         break;
 
         /**************************/