ArmVirtPkg/ArmVirtXen: add ArmVirtMemInfoLib implementation

Clone the existing ArmPlatformGetVirtualMemoryMap () for this platform,
clean it up slightly (by using a static buffer rather than a heap
allocation, and removing the support for uncached DRAM mappings), and
turn it into a new ArmVirtMemInfoLib implementation.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Julien Grall <julien.grall@linaro.org>

ArmVirtPkg/Library/XenVirtMemInfoLib/XenVirtMemInfoLib.c

@@ -0,0 +1,63 @@
+/** @file
+
+  Copyright (c) 2014-2017, Linaro Limited. All rights reserved.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Base.h>
+#include <Library/ArmLib.h>
+#include <Library/DebugLib.h>
+
+STATIC ARM_MEMORY_REGION_DESCRIPTOR  mVirtualMemoryTable[2];
+
+EFI_PHYSICAL_ADDRESS
+ArmGetPhysAddrTop (
+  VOID
+  );
+
+/**
+  Return the Virtual Memory Map of your platform
+
+  This Virtual Memory Map is used by MemoryInitPei Module to initialize the MMU
+  on your platform.
+
+  @param[out]   VirtualMemoryMap    Array of ARM_MEMORY_REGION_DESCRIPTOR
+                                    describing a Physical-to-Virtual Memory
+                                    mapping. This array must be ended by a
+                                    zero-filled entry. The allocated memory
+                                    will not be freed.
+
+**/
+VOID
+EFIAPI
+ArmVirtGetMemoryMap (
+  OUT ARM_MEMORY_REGION_DESCRIPTOR   **VirtualMemoryMap
+  )
+{
+  ASSERT (VirtualMemoryMap != NULL);
+
+  //
+  // Map the entire physical memory space as cached. The only device
+  // we care about is the GIC, which will be stage 2 mapped as a device
+  // by the hypervisor, overriding the cached mapping we install here.
+  //
+  mVirtualMemoryTable[0].PhysicalBase = 0x0;
+  mVirtualMemoryTable[0].VirtualBase  = 0x0;
+  mVirtualMemoryTable[0].Length       = ArmGetPhysAddrTop ();
+  mVirtualMemoryTable[0].Attributes   = ARM_MEMORY_REGION_ATTRIBUTE_WRITE_BACK;
+
+  mVirtualMemoryTable[1].PhysicalBase = 0x0;
+  mVirtualMemoryTable[1].VirtualBase  = 0x0;
+  mVirtualMemoryTable[1].Length       = 0x0;
+  mVirtualMemoryTable[1].Attributes   = 0x0;
+
+  *VirtualMemoryMap = mVirtualMemoryTable;
+}