Ovmf/Xen: move XenBusDxe hypercall code to separate library

This moves all of the Xen hypercall code that was private to XenBusDxe
to a new library class XenHypercallLib. This will allow us to reimplement
it for ARM, and to export the Xen hypercall functionality to other parts
of the code, such as a Xen console SerialPortLib driver.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16970 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Library/XenHypercallLib/Ia32/hypercall.nasm

@@ -0,0 +1,25 @@
+SECTION .text
+
+; INTN
+; EFIAPI
+; __XenHypercall2 (
+;   IN     VOID *HypercallAddr,
+;   IN OUT INTN Arg1,
+;   IN OUT INTN Arg2
+;   );
+global ASM_PFX(__XenHypercall2)
+ASM_PFX(__XenHypercall2):
+  ; Save only ebx, ecx is supposed to be a scratch register and needs to be
+  ; saved by the caller
+  push ebx
+  ; Copy HypercallAddr to eax
+  mov eax, [esp + 8]
+  ; Copy Arg1 to the register expected by Xen
+  mov ebx, [esp + 12]
+  ; Copy Arg2 to the register expected by Xen
+  mov ecx, [esp + 16]
+  ; Call HypercallAddr
+  call eax
+  pop ebx
+  ret
+

OvmfPkg/Library/XenHypercallLib/X64/hypercall.nasm

@@ -0,0 +1,26 @@
+DEFAULT REL
+SECTION .text
+
+; INTN
+; EFIAPI
+; __XenHypercall2 (
+;   IN     VOID *HypercallAddr,
+;   IN OUT INTN Arg1,
+;   IN OUT INTN Arg2
+;   );
+global ASM_PFX(__XenHypercall2)
+ASM_PFX(__XenHypercall2):
+  push rdi
+  push rsi
+  ; Copy HypercallAddr to rax
+  mov rax, rcx
+  ; Copy Arg1 to the register expected by Xen
+  mov rdi, rdx
+  ; Copy Arg2 to the register expected by Xen
+  mov rsi, r8
+  ; Call HypercallAddr
+  call rax
+  pop rsi
+  pop rdi
+  ret
+

OvmfPkg/Library/XenHypercallLib/XenHypercall.c

@@ -0,0 +1,63 @@
+/** @file
+  Functions to make Xen hypercalls.
+
+  Copyright (C) 2014, Citrix Ltd.
+
+  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 <PiDxe.h>
+
+#include <IndustryStandard/Xen/hvm/params.h>
+#include <IndustryStandard/Xen/memory.h>
+
+#include <Library/DebugLib.h>
+#include <Library/XenHypercallLib.h>
+
+UINT64
+XenHypercallHvmGetParam (
+  IN UINT32        Index
+  )
+{
+  xen_hvm_param_t     Parameter;
+  INTN                Error;
+
+  Parameter.domid = DOMID_SELF;
+  Parameter.index = Index;
+  Error = XenHypercall2 (__HYPERVISOR_hvm_op,
+                         HVMOP_get_param, (INTN) &Parameter);
+  if (Error != 0) {
+    DEBUG ((EFI_D_ERROR,
+            "XenHypercall: Error %d trying to get HVM parameter %d\n",
+            Error, Index));
+    return 0;
+  }
+  return Parameter.value;
+}
+
+INTN
+XenHypercallMemoryOp (
+  IN     UINTN Operation,
+  IN OUT VOID *Arguments
+  )
+{
+  return XenHypercall2 (__HYPERVISOR_memory_op,
+                        Operation, (INTN) Arguments);
+}
+
+INTN
+XenHypercallEventChannelOp (
+  IN     INTN Operation,
+  IN OUT VOID *Arguments
+  )
+{
+  return XenHypercall2 (__HYPERVISOR_event_channel_op,
+                        Operation, (INTN) Arguments);
+}

OvmfPkg/Library/XenHypercallLib/XenHypercallIntel.c

@@ -0,0 +1,77 @@
+/** @file
+  Xen Hypercall Library implementation for Intel architecture
+
+Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
+This program and the accompanying materials are licensed and made available under
+the terms and conditions of the BSD License that 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 <PiDxe.h>
+#include <Library/HobLib.h>
+#include <Library/DebugLib.h>
+#include <Guid/XenInfo.h>
+
+STATIC VOID    *HyperPage;
+
+//
+// Interface exposed by the ASM implementation of the core hypercall
+//
+INTN
+EFIAPI
+__XenHypercall2 (
+  IN     VOID *HypercallAddr,
+  IN OUT INTN Arg1,
+  IN OUT INTN Arg2
+  );
+
+/**
+  Library constructor: retrieves the Hyperpage address
+  from the gEfiXenInfoGuid HOB
+**/
+
+RETURN_STATUS
+EFIAPI
+XenHypercallLibIntelInit (
+  VOID
+  )
+{
+  EFI_HOB_GUID_TYPE   *GuidHob;
+  EFI_XEN_INFO        *XenInfo;
+
+  GuidHob = GetFirstGuidHob (&gEfiXenInfoGuid);
+  if (GuidHob == NULL) {
+    return RETURN_NOT_FOUND;
+  }
+  XenInfo = (EFI_XEN_INFO *) GET_GUID_HOB_DATA (GuidHob);
+  HyperPage = XenInfo->HyperPages;
+  return RETURN_SUCCESS;
+}
+
+/**
+  This function will put the two arguments in the right place (registers) and
+  invoke the hypercall identified by HypercallID.
+
+  @param HypercallID    The symbolic ID of the hypercall to be invoked
+  @param Arg1           First argument.
+  @param Arg2           Second argument.
+
+  @return   Return 0 if success otherwise it return an errno.
+**/
+INTN
+EFIAPI
+XenHypercall2 (
+  IN     UINTN  HypercallID,
+  IN OUT INTN   Arg1,
+  IN OUT INTN   Arg2
+  )
+{
+  ASSERT (HyperPage != NULL);
+
+  return __XenHypercall2 ((UINT8*)HyperPage + HypercallID * 32, Arg1, Arg2);
+}

OvmfPkg/Library/XenHypercallLib/XenHypercallLibIntel.inf

@@ -0,0 +1,52 @@
+## @file
+#  Xen Hypercall abstraction lib for Intel architecture
+#
+#  Copyright (c) 2014, Linaro Ltd. All rights reserved.<BR>
+#  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.
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = XenHypercallLibIntel
+  FILE_GUID                      = B5EE9A32-CA5A-49A8-82E3-ADA4CCB77C7C
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = XenHypercallLib|DXE_DRIVER UEFI_DRIVER
+  CONSTRUCTOR                    = XenHypercallLibIntelInit
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  XenHypercallIntel.c
+
+[Sources.IA32]
+  Ia32/hypercall.nasm
+
+[Sources.X64]
+  X64/hypercall.nasm
+
+[Sources]
+  XenHypercall.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[LibraryClasses]
+  BaseLib
+  HobLib
+  DebugLib
+
+[Guids]
+  gEfiXenInfoGuid