[PATCH] [RFC] x86/kconfig: Introduce CONFIG_PV and CONFIG_HVM

[Andrew Cooper <andrew.cooper3@citrix.com>]

Making PV and HVM guests individually compilable is useful as a reduction in
hypervisor size, and as an aid to enforcing clean API boundaries.

Introduce CONFIG_PV and CONFIG_HVM, although there is a lot of work to do
until either can actually be disabled.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
---
 xen/arch/x86/Kconfig               | 68 ++++++++++++++++++++++++++++----------
 xen/arch/x86/Makefile              |  4 +--
 xen/tools/kconfig/allrandom.config |  4 +++
 3 files changed, 56 insertions(+), 20 deletions(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 96ca2bf..87b03f3 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -32,6 +32,56 @@ menu "Architecture Features"
 
 source "arch/Kconfig"
 
+config PV
+	def_bool y
+	prompt "PV guest support" if EXPERT = "y"
+	depends on X86
+	---help---
+	  Support for Xen Paravirtual guests.
+
+	  Xen PV guests use Ring Deprivileging as a method of virtualisation.
+	  This requires no specific hardware support, but does require an OS
+	  capable of running PV under Xen.
+
+	  If unsure, say Y.
+
+	  TODO: This is a work in process, and Xen doesn't currently compile
+	  if this option is disabled.
+
+config HVM
+	def_bool y
+	prompt "HVM guest support" if EXPERT = "y"
+	depends on X86
+	---help---
+	  Support for Xen Hardware Virtual Machine guests.
+
+	  Xen HVM guests use hardware virtualisation extentions (Intel VT-x,
+	  AMD SVM) to run OSes.	 This requires a CPU with appropriate
+	  extentions, but can in principle run any OS, even if unmodified.
+
+	  If unsure, say Y.
+
+	  TODO: This is a work in process, and Xen doesn't currently compile
+	  if this option is disabled.
+
+config HVM_FEP
+	bool "HVM Forced Emulation Prefix support" if EXPERT = "y"
+	default DEBUG
+	depends on HVM
+	---help---
+	  Compiles in a feature that allows HVM guest to arbitrarily
+	  exercise the instruction emulator.
+
+	  This feature can only be enabled during boot time with
+	  appropriate hypervisor command line option. Please read
+	  hypervisor command line documentation before trying to use
+	  this feature.
+
+	  This is strictly for testing purposes, and not appropriate
+	  for use in production.
+
+	  If unsure, say N.
+
 config SHADOW_PAGING
         bool "Shadow Paging"
         default y
@@ -61,24 +111,6 @@ config BIGMEM
 
 	  If unsure, say N.
 
-config HVM_FEP
-	bool "HVM Forced Emulation Prefix support" if EXPERT = "y"
-	default DEBUG
-	---help---
-
-	  Compiles in a feature that allows HVM guest to arbitrarily
-	  exercise the instruction emulator.
-
-	  This feature can only be enabled during boot time with
-	  appropriate hypervisor command line option. Please read
-	  hypervisor command line documentation before trying to use
-	  this feature.
-
-	  This is strictly for testing purposes, and not appropriate
-	  for use in production.
-
-	  If unsure, say N.
-
 config TBOOT
 	def_bool y
 	prompt "Xen tboot support" if EXPERT = "y"
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 10f519e..d7c8970 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -1,10 +1,10 @@
 subdir-y += acpi
 subdir-y += cpu
 subdir-y += genapic
-subdir-y += hvm
+subdir-$(CONFIG_HVM) += hvm
 subdir-y += mm
 subdir-$(CONFIG_XENOPROF) += oprofile
-subdir-y += pv
+subdir-$(CONFIG_PV) += pv
 subdir-y += x86_64
 
 alternative-y := alternative.init.o
diff --git a/xen/tools/kconfig/allrandom.config b/xen/tools/kconfig/allrandom.config
index c7753ac..329ef59 100644
--- a/xen/tools/kconfig/allrandom.config
+++ b/xen/tools/kconfig/allrandom.config
@@ -1,3 +1,7 @@
 # Explicit option choices not subject to regular RANDCONFIG
 
 CONFIG_GCOV_FORMAT_AUTODETECT=y
+
+# Being able to compile-out guest subsystems is a work-in-progress.
+CONFIG_PV=y
+CONFIG_HVM=y
-- 
2.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel