[PATCH v4] x86/shim: don't permit HVM and PV_SHIM_EXCLUSIVE at the same time

[Jan Beulich <jbeulich@xxxxxxxx>]

This combination doesn't really make sense (and there likely are more);
in particular even if the code built with both options set, HVM guests
wouldn't work (and I think one wouldn't be able to create one in the
first place). The alternative here would be some presumably intrusive
#ifdef-ary to get this combination to actually build (but still not
work) again.

Fixes: 8b5b49ceb3d9 ("x86: don't include domctl and alike in shim-exclusive 
builds")
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
v4: Default HVM to !PV_SHIM, as suggested by Jürgen.
v2: Restore lost default setting.

--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -23,7 +23,7 @@ config X86
        select HAS_PDX
        select HAS_SCHED_GRANULARITY
        select HAS_UBSAN
-       select HAS_VPCI if !PV_SHIM_EXCLUSIVE && HVM
+       select HAS_VPCI if HVM
        select NEEDS_LIBELF
        select NUMA
 
@@ -90,9 +90,10 @@ config PV_LINEAR_PT
          If unsure, say Y.
 
 config HVM
-       def_bool !PV_SHIM_EXCLUSIVE
+       bool "HVM support"
+       depends on !PV_SHIM_EXCLUSIVE
+       default !PV_SHIM
        select IOREQ_SERVER
-       prompt "HVM support"
        ---help---
          Interfaces to support HVM domains.  HVM domains require hardware
          virtualisation extensions (e.g. Intel VT-x, AMD SVM), but can boot