1 files changed, 10 insertions, 14 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 48de4b890055..b8ce53861f68 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -52,6 +52,7 @@
 #define DstMem      (3<<1)      /* Memory operand. */
 #define DstAcc      (4<<1)      /* Destination Accumulator */
 #define DstDI       (5<<1)      /* Destination is in ES:(E)DI */
+#define DstMem64    (6<<1)      /* 64bit memory operand */
 #define DstMask     (7<<1)
 /* Source operand type. */
 #define SrcNone     (0<<4)      /* No source operand. */
@@ -360,7 +361,7 @@ static u32 group_table[] = {
         DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM | Lock,
         DstMem | SrcImmByte | ModRM | Lock, DstMem | SrcImmByte | ModRM | Lock,
         [Group9*8] =
-        0, ImplicitOps | ModRM | Lock, 0, 0, 0, 0, 0, 0,
+        0, DstMem64 | ModRM | Lock, 0, 0, 0, 0, 0, 0,
 };
 
 static u32 group2_table[] = {
@@ -1205,6 +1206,7 @@ done_prefixes:
                          c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
                 break;
         case DstMem:
+        case DstMem64:
                 if ((c->d & ModRM) && c->modrm_mod == 3) {
                         c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
                         c->dst.type = OP_REG;
@@ -1214,7 +1216,10 @@ done_prefixes:
                 }
                 c->dst.type = OP_MEM;
                 c->dst.ptr = (unsigned long *)c->modrm_ea;
-                c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+                if ((c->d & DstMask) == DstMem64)
+                        c->dst.bytes = 8;
+                else
+                        c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
                 c->dst.val = 0;
                 if (c->d & BitOp) {
                         unsigned long mask = ~(c->dst.bytes * 8 - 1);
@@ -1706,12 +1711,7 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
                                struct x86_emulate_ops *ops)
 {
         struct decode_cache *c = &ctxt->decode;
-        u64 old, new;
-        int rc;
-
-        rc = ops->read_emulated(c->modrm_ea, &old, 8, ctxt->vcpu);
-        if (rc != X86EMUL_CONTINUE)
-                return rc;
+        u64 old = c->dst.orig_val;
 
         if (((u32) (old >> 0) != (u32) c->regs[VCPU_REGS_RAX]) ||
             ((u32) (old >> 32) != (u32) c->regs[VCPU_REGS_RDX])) {
@@ -1719,15 +1719,12 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
                 c->regs[VCPU_REGS_RAX] = (u32) (old >> 0);
                 c->regs[VCPU_REGS_RDX] = (u32) (old >> 32);
                 ctxt->eflags &= ~EFLG_ZF;
-
         } else {
-                new = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
+                c->dst.val = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
                        (u32) c->regs[VCPU_REGS_RBX];
 
-                rc = ops->cmpxchg_emulated(c->modrm_ea, &old, &new, 8, ctxt->vcpu);
-                if (rc != X86EMUL_CONTINUE)
-                        return rc;
                 ctxt->eflags |= EFLG_ZF;
+                c->lock_prefix = 1;
         }
         return X86EMUL_CONTINUE;
 }
@@ -3245,7 +3242,6 @@ twobyte_insn:
                 rc = emulate_grp9(ctxt, ops);
                 if (rc != X86EMUL_CONTINUE)
                         goto done;
-                c->dst.type = OP_NONE;
                 break;
         }
         goto writeback;