KVM: x86 emulator: emulate SGDT/SIDT

Opcodes 0F 01 /0 and 0F 01 /1
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/emulate.c

@@ -3026,6 +3026,35 @@ static int em_vmcall(struct x86_emulate_ctxt *ctxt)
 	return X86EMUL_CONTINUE;
 }
 
+static int emulate_store_desc_ptr(struct x86_emulate_ctxt *ctxt,
+				  void (*get)(struct x86_emulate_ctxt *ctxt,
+					      struct desc_ptr *ptr))
+{
+	struct desc_ptr desc_ptr;
+
+	if (ctxt->mode == X86EMUL_MODE_PROT64)
+		ctxt->op_bytes = 8;
+	get(ctxt, &desc_ptr);
+	if (ctxt->op_bytes == 2) {
+		ctxt->op_bytes = 4;
+		desc_ptr.address &= 0x00ffffff;
+	}
+	/* Disable writeback. */
+	ctxt->dst.type = OP_NONE;
+	return segmented_write(ctxt, ctxt->dst.addr.mem,
+			       &desc_ptr, 2 + ctxt->op_bytes);
+}
+
+static int em_sgdt(struct x86_emulate_ctxt *ctxt)
+{
+	return emulate_store_desc_ptr(ctxt, ctxt->ops->get_gdt);
+}
+
+static int em_sidt(struct x86_emulate_ctxt *ctxt)
+{
+	return emulate_store_desc_ptr(ctxt, ctxt->ops->get_idt);
+}
+
 static int em_lgdt(struct x86_emulate_ctxt *ctxt)
 {
 	struct desc_ptr desc_ptr;
@@ -3485,8 +3514,8 @@ static struct opcode group6[] = {
 };
 
 static struct group_dual group7 = { {
-	DI(Mov | DstMem | Priv,			sgdt),
-	DI(Mov | DstMem | Priv,			sidt),
+	II(Mov | DstMem | Priv,			em_sgdt, sgdt),
+	II(Mov | DstMem | Priv,			em_sidt, sidt),
 	II(SrcMem | Priv,			em_lgdt, lgdt),
 	II(SrcMem | Priv,			em_lidt, lidt),
 	II(SrcNone | DstMem | Mov,		em_smsw, smsw), N,