xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and CONFIG_XEN_PVH

In order to pave the way for hypervisors other than Xen to use the PVH
entry point for VMs, we need to factor the PVH entry code into Xen specific
and hypervisor agnostic components. The first step in doing that, is to
create a new config option for PVH entry that can be enabled
independently from CONFIG_XEN.
Signed-off-by: Maran Wilson <maran.wilson@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

arch/x86/Kconfig

@@ -796,6 +796,12 @@ config KVM_GUEST
 	  underlying device model, the host provides the guest with
 	  timing infrastructure such as time of day, and system time
 
+config PVH
+	bool "Support for running PVH guests"
+	---help---
+	  This option enables the PVH entry point for guest virtual machines
+	  as specified in the x86/HVM direct boot ABI.
+
 config KVM_DEBUG_FS
 	bool "Enable debug information for KVM Guests in debugfs"
 	depends on KVM_GUEST && DEBUG_FS

arch/x86/kernel/head_64.S

@@ -386,7 +386,7 @@ NEXT_PAGE(early_dynamic_pgts)
 
 	.data
 
-#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
+#if defined(CONFIG_XEN_PV) || defined(CONFIG_PVH)
 NEXT_PGD_PAGE(init_top_pgt)
 	.quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
 	.org    init_top_pgt + L4_PAGE_OFFSET*8, 0

arch/x86/xen/Kconfig

@@ -74,6 +74,7 @@ config XEN_DEBUG_FS
 	  Enabling this option may incur a significant performance overhead.
 
 config XEN_PVH
-	bool "Support for running as a PVH guest"
+	bool "Support for running as a Xen PVH guest"
 	depends on XEN && XEN_PVHVM && ACPI
+	select PVH
 	def_bool n