[PATCH] x86/shadow: depend on PV || HVM

[Jan Beulich <jbeulich@xxxxxxxx>]

With the building of guest_?.o now depending on PV or HVM, without
further #ifdef-ary shadow code won't link anymore when !PV && !HVM.
Since this isn't a useful configuration anyway, exclude shadow code from
being built in this case.

Fixes: aff8bf94ce65 ("x86/shadow: only 4-level guest code needs building when 
!HVM")
Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -121,6 +121,7 @@ config XEN_SHSTK
 config SHADOW_PAGING
        bool "Shadow Paging"
        default !PV_SHIM_EXCLUSIVE
+       depends on PV || HVM
        ---help---
 
           Shadow paging is a software alternative to hardware paging support