[RFC 10/10] x86/hvm: make AMD-V and Intel VT-x support configurable

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

Provide the user with configuration control over the cpu virtualization support
in Xen by making AMD_SVM and INTEL_VMX options user selectable.

To preserve the current default behavior, both options depend on HVM and
default to Y.

To prevent users from unknowingly disabling virtualization support, make the
controls user selectable only if EXPERT is enabled.

No functional change intended.

Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
---
 xen/arch/x86/Kconfig | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 2a72111c23..fce40f08b1 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -118,10 +118,24 @@ config HVM
          If unsure, say Y.
 
 config AMD_SVM
-       def_bool y if HVM
+       bool "AMD-V" if EXPERT
+       depends on HVM
+       default y
+       help
+         Enables virtual machine extensions on platforms that implement the
+         AMD Virtualization Technology (AMD-V).
+         If your system includes a processor with AMD-V support, say Y.
+         If in doubt, say Y.
 
 config INTEL_VMX
-       def_bool y if HVM
+       bool "Intel VT-x" if EXPERT
+       depends on HVM
+       default y
+       help
+         Enables virtual machine extensions on platforms that implement the
+         Intel Virtualization Technology (Intel VT-x).
+         If your system includes a processor with Intel VT-x support, say Y.
+         If in doubt, say Y.
 
 config XEN_SHSTK
        bool "Supervisor Shadow Stacks"
-- 
2.37.2