From a154f420147b0a3f449bb52da1e76dabef3478a5 Mon Sep 17 00:00:00 2001
From: Anthony PERARD <anthony.perard@citrix.com>
Date: Wed, 29 Oct 2014 06:48:59 +0000
Subject: [PATCH] OvmfPkg/XenBusDxe: Add device state struct and create an
 ExitBoot services event.

The ExitBoot event is used to disconnect from the device before the
next operating system start using them.

Change in V3:
- use the variable mMyDevice to prevent the driver from
  starting twice (if there is two different PCI devices).
- free(dev) on exit

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16259 6f19259b-4bc3-4df7-8a09-765794883524
---
 OvmfPkg/XenBusDxe/XenBusDxe.c | 56 +++++++++++++++++++++++++++++++++--
 OvmfPkg/XenBusDxe/XenBusDxe.h | 11 +++++++
 2 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.c b/OvmfPkg/XenBusDxe/XenBusDxe.c
index 7f297bdeae..f3c74e1fbe 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.c
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.c
@@ -43,6 +43,9 @@ EFI_DRIVER_BINDING_PROTOCOL gXenBusDxeDriverBinding = {
 };
 
 
+STATIC EFI_LOCK       mMyDeviceLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_CALLBACK);
+STATIC XENBUS_DEVICE *mMyDevice = NULL;
+
 /**
   Unloads an image.
 
@@ -216,6 +219,19 @@ XenBusDxeDriverBindingSupported (
   return Status;
 }
 
+VOID
+EFIAPI
+NotifyExitBoot (
+  IN EFI_EVENT Event,
+  IN VOID *Context
+  )
+{
+  XENBUS_DEVICE *Dev = Context;
+
+  gBS->DisconnectController(Dev->ControllerHandle,
+                            Dev->This->DriverBindingHandle, NULL);
+}
+
 /**
   Starts a bus controller.
 
@@ -259,7 +275,37 @@ XenBusDxeDriverBindingStart (
   IN EFI_DEVICE_PATH_PROTOCOL     *RemainingDevicePath OPTIONAL
   )
 {
-  return EFI_UNSUPPORTED;
+  EFI_STATUS Status;
+  XENBUS_DEVICE *Dev;
+
+  Dev = AllocateZeroPool (sizeof (*Dev));
+  Dev->Signature = XENBUS_DEVICE_SIGNATURE;
+  Dev->This = This;
+  Dev->ControllerHandle = ControllerHandle;
+
+  EfiAcquireLock (&mMyDeviceLock);
+  if (mMyDevice != NULL) {
+    EfiReleaseLock (&mMyDeviceLock);
+    //
+    // There is already a XenBus running, only one can be used at a time.
+    //
+    Status = EFI_ALREADY_STARTED;
+    goto ErrorAllocated;
+  }
+  mMyDevice = Dev;
+  EfiReleaseLock (&mMyDeviceLock);
+
+  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
+                             NotifyExitBoot,
+                             (VOID*) Dev,
+                             &Dev->ExitBootEvent);
+  ASSERT_EFI_ERROR (Status);
+
+  return EFI_SUCCESS;
+
+ErrorAllocated:
+  FreePool (Dev);
+  return Status;
 }
 
 /**
@@ -297,5 +343,11 @@ XenBusDxeDriverBindingStop (
   IN EFI_HANDLE                   *ChildHandleBuffer OPTIONAL
   )
 {
-  return EFI_UNSUPPORTED;
+  XENBUS_DEVICE *Dev = mMyDevice;
+
+  gBS->CloseEvent (Dev->ExitBootEvent);
+
+  mMyDevice = NULL;
+  FreePool (Dev);
+  return EFI_SUCCESS;
 }
diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.h b/OvmfPkg/XenBusDxe/XenBusDxe.h
index bcd9f3cef3..d7537f3fe5 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.h
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.h
@@ -74,4 +74,15 @@ extern EFI_COMPONENT_NAME_PROTOCOL  gXenBusDxeComponentName;
 #define PCI_DEVICE_ID_XEN_PLATFORM       0x0001
 
 
+typedef struct _XENBUS_DEVICE XENBUS_DEVICE;
+
+// Have the state of the driver.
+#define XENBUS_DEVICE_SIGNATURE SIGNATURE_32 ('X','B','s','t')
+struct _XENBUS_DEVICE {
+  UINT32                        Signature;
+  EFI_DRIVER_BINDING_PROTOCOL   *This;
+  EFI_HANDLE                    ControllerHandle;
+  EFI_EVENT                     ExitBootEvent;
+};
+
 #endif
-- 
2.39.2