KVM: x86 emulator: Add support for mov seg, r (0x8e) instruction

Add support for mov r, sreg (0x8c) instruction.

[avi: drop the sreg decoding table in favor of 1:1 encoding]

Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net>
Signed-off-by: Laurent Vivier <laurent.vivier@bull.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 21d7ff6a8ecd..b049b6bf9a71 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -138,7 +138,8 @@ static u16 opcode_table[256] = {
         /* 0x88 - 0x8F */
         ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov,
         ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
-        0, ModRM | DstReg, 0, Group | Group1A,
+        0, ModRM | DstReg,
+        DstReg | SrcMem | ModRM | Mov, Group | Group1A,
         /* 0x90 - 0x9F */
         0, 0, 0, 0, 0, 0, 0, 0,
         0, 0, 0, 0, ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
@@ -1520,6 +1521,28 @@ special_insn:
         case 0x8d: /* lea r16/r32, m */
                 c->dst.val = c->modrm_ea;
                 break;
+        case 0x8e: { /* mov seg, r/m16 */
+                uint16_t sel;
+                int type_bits;
+                int err;
+
+                sel = c->src.val;
+                if (c->modrm_reg <= 5) {
+                        type_bits = (c->modrm_reg == 1) ? 9 : 1;
+                        err = kvm_load_segment_descriptor(ctxt->vcpu, sel,
+                                                          type_bits, c->modrm_reg);
+                } else {
+                        printk(KERN_INFO "Invalid segreg in modrm byte 0x%02x\n",
+                                        c->modrm);
+                        goto cannot_emulate;
+                }
+
+                if (err < 0)
+                        goto cannot_emulate;
+
+                c->dst.type = OP_NONE;  /* Disable writeback. */
+                break;
+        }
         case 0x8f:              /* pop (sole member of Grp1a) */
                 rc = emulate_grp1a(ctxt, ops);
                 if (rc != 0)