KVM: x86 emulator: Make emulate_pop() a little more generic

Allow emulate_pop() to read into arbitrary memory rather than just the
source operand.  Needed for complicated instructions like far returns.

Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 54fb09889a80e33831797e25e8895ba901fc5192..94459f313f12d259ceceb249f8256d06782847f9 100644 (file)
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -1136,18 +1136,19 @@ static inline void emulate_push(struct x86_emulate_ctxt *ctxt)
 }
 
 static int emulate_pop(struct x86_emulate_ctxt *ctxt,
-                      struct x86_emulate_ops *ops)
+                      struct x86_emulate_ops *ops,
+                      void *dest, int len)
 {
        struct decode_cache *c = &ctxt->decode;
        int rc;
 
        rc = ops->read_emulated(register_address(c, ss_base(ctxt),
                                                 c->regs[VCPU_REGS_RSP]),
-                               &c->src.val, c->src.bytes, ctxt->vcpu);
+                               dest, len, ctxt->vcpu);
        if (rc != 0)
                return rc;
 
-       register_address_increment(c, &c->regs[VCPU_REGS_RSP], c->src.bytes);
+       register_address_increment(c, &c->regs[VCPU_REGS_RSP], len);
        return rc;
 }
 
@@ -1157,11 +1158,9 @@ static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
        struct decode_cache *c = &ctxt->decode;
        int rc;
 
-       c->src.bytes = c->dst.bytes;
-       rc = emulate_pop(ctxt, ops);
+       rc = emulate_pop(ctxt, ops, &c->dst.val, c->dst.bytes);
        if (rc != 0)
                return rc;
-       c->dst.val = c->src.val;
        return 0;
 }
 
@@ -1467,11 +1466,9 @@ special_insn:
                break;
        case 0x58 ... 0x5f: /* pop reg */
        pop_instruction:
-               c->src.bytes = c->op_bytes;
-               rc = emulate_pop(ctxt, ops);
+               rc = emulate_pop(ctxt, ops, &c->dst.val, c->op_bytes);
                if (rc != 0)
                        goto done;
-               c->dst.val = c->src.val;
                break;
        case 0x63:              /* movsxd */
                if (ctxt->mode != X86EMUL_MODE_PROT64)