[PATCH v3 33/35] OvmfPkg: Introduce XenIoPvhDxe to initialize Grant Tables

["Anthony PERARD" <anthony.perard@citrix.com>]

XenIoPvhDxe use XenIoMmioLib to reserve some space to be use by the
Grant Tables.

The call is only done if it is necessary, we simply detect if the
guest is PVH, as in this case there is currently no PCI bus, and no
PCI Xen platform device which would start the XenIoPciDxe and allocate
the space for the Grant Tables.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---

Notes:
    v3:
    - downgrade type to DXE_DRIVER
    - use SPDX
    - rework InitializeXenIoPvhDxe, and handle errors properly.
    - Free the reserved allocation in ExitBootServices even if the XenIo
      protocol could successfully been uninstalled.
    
    v2:
    - do allocation in EntryPoint like the other user of XenIoMmioLib.
    - allocate memory instead of hardcoded addr.
    - cleanup, add copyright
    - detect if we are running in PVH mode

 OvmfPkg/OvmfXen.dsc                 |   2 +
 OvmfPkg/OvmfXen.fdf                 |   1 +
 OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf |  34 +++++++++
 OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.c   | 108 ++++++++++++++++++++++++++++
 4 files changed, 145 insertions(+)
 create mode 100644 OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf
 create mode 100644 OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.c

diff --git a/OvmfPkg/OvmfXen.dsc b/OvmfPkg/OvmfXen.dsc
index 487bada64d..af92ce3ed2 100644
--- a/OvmfPkg/OvmfXen.dsc
+++ b/OvmfPkg/OvmfXen.dsc
@@ -196,6 +196,7 @@ [LibraryClasses]
   OrderedCollectionLib|MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.inf
   XenHypercallLib|OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
   XenPlatformLib|OvmfPkg/Library/XenPlatformLib/XenPlatformLib.inf
+  XenIoMmioLib|OvmfPkg/Library/XenIoMmioLib/XenIoMmioLib.inf
 
   Tcg2PhysicalPresenceLib|OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.inf
 
@@ -583,6 +584,7 @@ [Components]
       NULL|OvmfPkg/Csm/LegacyBootMaintUiLib/LegacyBootMaintUiLib.inf
 !endif
   }
+  OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf
   OvmfPkg/XenIoPciDxe/XenIoPciDxe.inf
   OvmfPkg/XenBusDxe/XenBusDxe.inf
   OvmfPkg/XenPvBlkDxe/XenPvBlkDxe.inf
diff --git a/OvmfPkg/OvmfXen.fdf b/OvmfPkg/OvmfXen.fdf
index 5c1a925d6a..517a492f14 100644
--- a/OvmfPkg/OvmfXen.fdf
+++ b/OvmfPkg/OvmfXen.fdf
@@ -309,6 +309,7 @@ [FV.DXEFV]
 INF  MdeModulePkg/Universal/Metronome/Metronome.inf
 INF  PcAtChipsetPkg/PcatRealTimeClockRuntimeDxe/PcatRealTimeClockRuntimeDxe.inf
 
+INF  OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf
 INF  OvmfPkg/XenIoPciDxe/XenIoPciDxe.inf
 INF  OvmfPkg/XenBusDxe/XenBusDxe.inf
 INF  OvmfPkg/XenPvBlkDxe/XenPvBlkDxe.inf
diff --git a/OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf b/OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf
new file mode 100644
index 0000000000..a093d48fde
--- /dev/null
+++ b/OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.inf
@@ -0,0 +1,34 @@
+## @file
+#  Driver for the XenIo protocol
+#
+#  Copyright (c) 2019, Citrix Systems, Inc.
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION               = 0x00010005
+  BASE_NAME                 = XenIoPvhDxe
+  FILE_GUID                 = 7a567cc4-0e75-4d7a-a305-c3db109b53ad
+  MODULE_TYPE               = DXE_DRIVER
+  VERSION_STRING            = 1.0
+  ENTRY_POINT               = InitializeXenIoPvhDxe
+
+[Packages]
+  MdePkg/MdePkg.dec
+  OvmfPkg/OvmfPkg.dec
+
+[Sources]
+  XenIoPvhDxe.c
+
+[LibraryClasses]
+  DebugLib
+  MemoryAllocationLib
+  UefiBootServicesTableLib
+  UefiDriverEntryPoint
+  XenIoMmioLib
+  XenPlatformLib
+
+[Depex]
+  TRUE
diff --git a/OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.c b/OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.c
new file mode 100644
index 0000000000..88a394bf91
--- /dev/null
+++ b/OvmfPkg/XenIoPvhDxe/XenIoPvhDxe.c
@@ -0,0 +1,108 @@
+/** @file
+
+  Driver for the XenIo protocol
+
+  This driver simply allocate space for the grant tables.
+
+  Copyright (c) 2019, Citrix Systems, Inc.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/DebugLib.h>
+#include <Library/XenIoMmioLib.h>
+#include <Library/XenPlatformLib.h>
+
+typedef struct {
+  EFI_HANDLE    XenIoHandle;
+  EFI_EVENT     ExitBootEvent;
+  VOID          *Allocation;
+} XEN_IO_PVH_STATE;
+
+//
+// Value should be the same as NR_GRANT_FRAMES in XenBusDxe
+//
+#define XEN_GRANT_FRAMES 4
+
+STATIC
+VOID
+EFIAPI
+XenIoPvhDxeNotifyExitBoot (
+  IN EFI_EVENT  Event,
+  IN VOID       *Context
+  )
+{
+  XEN_IO_PVH_STATE *State;
+  EFI_STATUS Status;
+
+  State = Context;
+
+  gBS->CloseEvent(&State->ExitBootEvent);
+  Status = XenIoMmioUninstall(State->XenIoHandle);
+  if (Status == EFI_SUCCESS) {
+    //
+    // Only free the reserved space for grant table if no driver is using it.
+    //
+    FreePages (State->Allocation, XEN_GRANT_FRAMES);
+  }
+  FreePool (State);
+}
+
+EFI_STATUS
+EFIAPI
+InitializeXenIoPvhDxe (
+  IN EFI_HANDLE       ImageHandle,
+  IN EFI_SYSTEM_TABLE *SystemTable
+  )
+{
+  VOID *Allocation;
+  EFI_STATUS Status;
+  XEN_IO_PVH_STATE *State;
+
+  State = NULL;
+  Allocation = NULL;
+
+  if (! XenPvhDetected ()) {
+    return EFI_UNSUPPORTED;
+  }
+
+  State = AllocatePool (sizeof (*State));
+  if (State == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Error;
+  }
+
+  Allocation = AllocateReservedPages (XEN_GRANT_FRAMES);
+  if (Allocation == NULL) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Error;
+  }
+
+  State->XenIoHandle = NULL;
+  Status = XenIoMmioInstall (&State->XenIoHandle, (UINTN) Allocation);
+  if (EFI_ERROR (Status)) {
+    goto Error;
+  }
+
+  State->Allocation = Allocation;
+  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
+                  XenIoPvhDxeNotifyExitBoot, State, &State->ExitBootEvent);
+  ASSERT_EFI_ERROR (Status);
+
+  return EFI_SUCCESS;
+
+Error:
+  if (State != NULL && State->XenIoHandle != NULL) {
+    XenIoMmioUninstall(State->XenIoHandle);
+  }
+  if (Allocation != NULL) {
+    FreePages (Allocation, XEN_GRANT_FRAMES);
+  }
+  if (State != NULL) {
+    FreePool (State);
+  }
+  return Status;
+}
-- 
Anthony PERARD