Kernel: Move VMWare backdoor communication code to the x86 directory

The VMWare backdoor handling code involves many x86-specific
instructions and therefore should be in the Arch/x86 directory. This
ensures we can easily omit the code in compile-time for non-x86 builds.

Kernel/Arch/x86/Hypervisor/VMWareBackdoor.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+#include <AK/kmalloc.h>
+#include <Kernel/API/MousePacket.h>
+
+namespace Kernel {
+
+#define VMMOUSE_GETVERSION 10
+#define VMMOUSE_DATA 39
+#define VMMOUSE_STATUS 40
+#define VMMOUSE_COMMAND 41
+
+struct VMWareCommand {
+    union {
+        u32 ax;
+        u32 magic;
+    };
+    union {
+        u32 bx;
+        u32 size;
+    };
+    union {
+        u32 cx;
+        u32 command;
+    };
+    union {
+        u32 dx;
+        u32 port;
+    };
+    u32 si;
+    u32 di;
+};
+
+class VMWareBackdoor {
+
+public:
+    VMWareBackdoor();
+    static VMWareBackdoor* the();
+
+    bool vmmouse_is_absolute() const;
+    void enable_absolute_vmmouse();
+    void disable_absolute_vmmouse();
+    void send(VMWareCommand& command);
+
+    u16 read_mouse_status_queue_size();
+    MousePacket receive_mouse_packet();
+
+private:
+    void send_high_bandwidth(VMWareCommand& command);
+    void get_high_bandwidth(VMWareCommand& command);
+    bool detect_vmmouse();
+    bool m_vmmouse_absolute { false };
+};
+
+}