cloud-hypervisor: Add the architecture crates

Both crates are based on Firecracker commit 9cdb5b2.
They are ported to the new memory model and tests have been fixed
accordingly.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

arch/src/x86_64/layout.rs

@@ -0,0 +1,25 @@
+// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// Portions Copyright 2017 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the THIRD-PARTY file.
+
+use vm_memory::GuestAddress;
+
+/// Magic addresses externally used to lay out x86_64 VMs.
+
+/// Initial stack for the boot CPU.
+pub const BOOT_STACK_START: GuestAddress = GuestAddress(0x8000);
+pub const BOOT_STACK_POINTER: GuestAddress = GuestAddress(0x8ff0);
+
+/// Kernel command line start address.
+pub const CMDLINE_START: GuestAddress = GuestAddress(0x20000);
+/// Kernel command line start address maximum size.
+pub const CMDLINE_MAX_SIZE: usize = 0x10000;
+
+/// Address for the TSS setup.
+pub const KVM_TSS_ADDRESS: GuestAddress = GuestAddress(0xfffbd000);
+
+/// The 'zero page', a.k.a linux kernel bootparams.
+pub const ZERO_PAGE_START: GuestAddress = GuestAddress(0x7000);