This enables very aggressive DCE passes on single-vendor builds in later
patches, as it will allow most vendor checks to become statically chosen
branches. A lot of statics go away and a lot more inlining will be allowed.

A prerequisite for such optimisation is to expand Kconfig to have the
full set of vendors. Adds Hygon, Centaur, Shanghai and the unknown-vendor
path. Have Hygon select AMD, and Centaur|Shanghai select Intel.

Not a functional change.

Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
---
rfc -> v1:
  * s/depends on/select/
  * s/UNKNOWN_CPU/UNKNOWN_CPU_VENDOR/
  * Removed "if unsure, say Y"
---
 xen/arch/x86/Kconfig.cpu  | 43 +++++++++++++++++++++++++++++++++++++++
 xen/arch/x86/cpu/Makefile |  6 +++---
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/Kconfig.cpu b/xen/arch/x86/Kconfig.cpu
index 5fb18db1aa..f895cfe97a 100644
--- a/xen/arch/x86/Kconfig.cpu
+++ b/xen/arch/x86/Kconfig.cpu
@@ -19,4 +19,47 @@ config INTEL
 	  May be turned off in builds targetting other vendors.  Otherwise,
 	  must be enabled for Xen to work suitably on Intel platforms.
 
+config HYGON
+	bool "Support Hygon CPUs"
+	select AMD
+	default y
+	help
+	  Detection, tunings and quirks for Hygon platforms.
+
+	  May be turned off in builds targetting other vendors.  Otherwise,
+	  must be enabled for Xen to work suitably on Hygon platforms.
+
+
+config CENTAUR
+	bool "Support Centaur CPUs"
+	select INTEL
+	default y
+	help
+	  Detection, tunings and quirks for Centaur platforms.
+
+	  May be turned off in builds targetting other vendors.  Otherwise,
+	  must be enabled for Xen to work suitably on Centaur platforms.
+
+config SHANGHAI
+	bool "Support Shanghai CPUs"
+	select INTEL
+	default y
+	help
+	  Detection, tunings and quirks for Shanghai platforms.
+
+	  May be turned off in builds targetting other vendors.  Otherwise,
+	  must be enabled for Xen to work suitably on Shanghai platforms.
+
+config UNKNOWN_CPU_VENDOR
+	bool "Support unknown CPU vendors"
+	default y
+	help
+	  This option prevents a panic on boot when the host CPU vendor isn't
+	  supported by going into a legacy compatibility mode and not applying
+	  any relevant tunings or quirks.
+
+	  Not selecting this options while selecting multiple vendors doesn't have
+	  any major effect on code size, but selecting a single vendor with this
+	  option cleared produces a much smaller build.
+
 endmenu
diff --git a/xen/arch/x86/cpu/Makefile b/xen/arch/x86/cpu/Makefile
index 7cfe28b7ec..84b060aa41 100644
--- a/xen/arch/x86/cpu/Makefile
+++ b/xen/arch/x86/cpu/Makefile
@@ -3,13 +3,13 @@ obj-y += microcode/
 obj-y += mtrr/
 
 obj-y += amd.o
-obj-y += centaur.o
+obj-$(CONFIG_CENTAUR) += centaur.o
 obj-y += common.o
-obj-y += hygon.o
 obj-y += intel.o
+obj-$(CONFIG_HYGON) += hygon.o
 obj-y += intel_cacheinfo.o
 obj-$(CONFIG_INTEL) += mwait-idle.o
-obj-y += shanghai.o
+obj-$(CONFIG_SHANGHAI) += shanghai.o
 obj-y += vpmu.o
 obj-$(CONFIG_AMD) += vpmu_amd.o
 obj-$(CONFIG_INTEL) += vpmu_intel.o
-- 
2.43.0