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/XenBusDxe/XenBusDxe.inf

@@ -34,8 +34,6 @@
   DriverBinding.h
   ComponentName.c
   ComponentName.h
-  XenHypercall.c
-  XenHypercall.h
   InterlockedCompareExchange16.c
   InterlockedCompareExchange16.h
   GrantTable.c
@@ -49,12 +47,10 @@
   Helpers.c
 
 [Sources.IA32]
-  Ia32/hypercall.nasm
   Ia32/InterlockedCompareExchange16.nasm
   Ia32/TestAndClearBit.nasm
 
 [Sources.X64]
-  X64/hypercall.nasm
   X64/InterlockedCompareExchange16.nasm
   X64/TestAndClearBit.nasm
 
@@ -67,8 +63,7 @@
   UefiLib
   DevicePathLib
   DebugLib
-  HobLib
-
+  XenHypercallLib
 
 [Protocols]
   gEfiDriverBindingProtocolGuid
@@ -77,7 +72,3 @@
   gEfiComponentNameProtocolGuid
   gXenBusProtocolGuid
 
-
-[Guids]
-  gEfiXenInfoGuid
-