[RFC 01/10] x86: introduce AMD-V and Intel VT-x Kconfig options

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

Introduce two new Kconfig options, AMD_SVM and INTEL_VMX, to allow code
specific to each virtualization technology to be separated and, when not
required, stripped.
AMD_SVM will be used to enable virtual machine extensions on platforms that
implement the AMD Virtualization Technology (AMD-V).
INTEL_VMX will be used to enable virtual machine extensions on platforms that
implement the Intel Virtualization Technology (Intel VT-x).

Both features depend on HVM support.

Since, at this point, disabling any of them would cause Xen to not compile,
the options are enabled by default if HVM and are not selectable by the user.

No functional change intended.

Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
---
 xen/arch/x86/Kconfig            | 6 ++++++
 xen/arch/x86/cpu/Makefile       | 4 +++-
 xen/arch/x86/hvm/Makefile       | 4 ++--
 xen/arch/x86/mm/Makefile        | 3 ++-
 xen/arch/x86/mm/hap/Makefile    | 2 +-
 xen/drivers/passthrough/Kconfig | 2 +-
 6 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 6a7825f4ba..2a72111c23 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -117,6 +117,12 @@ config HVM
 
          If unsure, say Y.
 
+config AMD_SVM
+       def_bool y if HVM
+
+config INTEL_VMX
+       def_bool y if HVM
+
 config XEN_SHSTK
        bool "Supervisor Shadow Stacks"
        depends on HAS_AS_CET_SS
diff --git a/xen/arch/x86/cpu/Makefile b/xen/arch/x86/cpu/Makefile
index 35561fe51d..08bdf4abb8 100644
--- a/xen/arch/x86/cpu/Makefile
+++ b/xen/arch/x86/cpu/Makefile
@@ -10,4 +10,6 @@ obj-y += intel.o
 obj-y += intel_cacheinfo.o
 obj-y += mwait-idle.o
 obj-y += shanghai.o
-obj-y += vpmu.o vpmu_amd.o vpmu_intel.o
+obj-y += vpmu.o
+obj-$(CONFIG_AMD_SVM) += vpmu_amd.o
+obj-$(CONFIG_INTEL_VMX) += vpmu_intel.o
diff --git a/xen/arch/x86/hvm/Makefile b/xen/arch/x86/hvm/Makefile
index 3464191544..4c1fa5c6c2 100644
--- a/xen/arch/x86/hvm/Makefile
+++ b/xen/arch/x86/hvm/Makefile
@@ -1,5 +1,5 @@
-obj-y += svm/
-obj-y += vmx/
+obj-$(CONFIG_AMD_SVM) += svm/
+obj-$(CONFIG_INTEL_VMX) += vmx/
 obj-y += viridian/
 
 obj-y += asid.o
diff --git a/xen/arch/x86/mm/Makefile b/xen/arch/x86/mm/Makefile
index 0803ac9297..c53c94308a 100644
--- a/xen/arch/x86/mm/Makefile
+++ b/xen/arch/x86/mm/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_MEM_SHARING) += mem_sharing.o
 obj-$(CONFIG_HVM) += nested.o
 obj-$(CONFIG_HVM) += p2m.o
 obj-y += p2m-basic.o
-obj-$(CONFIG_HVM) += p2m-ept.o p2m-pod.o p2m-pt.o
+obj-$(CONFIG_HVM) += p2m-pod.o p2m-pt.o
+obj-$(CONFIG_INTEL_VMX) += p2m-ept.o
 obj-y += paging.o
 obj-y += physmap.o
diff --git a/xen/arch/x86/mm/hap/Makefile b/xen/arch/x86/mm/hap/Makefile
index 8ef54b1faa..67c29b2162 100644
--- a/xen/arch/x86/mm/hap/Makefile
+++ b/xen/arch/x86/mm/hap/Makefile
@@ -3,4 +3,4 @@ obj-y += guest_walk_2.o
 obj-y += guest_walk_3.o
 obj-y += guest_walk_4.o
 obj-y += nested_hap.o
-obj-y += nested_ept.o
+obj-$(CONFIG_INTEL_VMX) += nested_ept.o
diff --git a/xen/drivers/passthrough/Kconfig b/xen/drivers/passthrough/Kconfig
index 864fcf3b0c..f95e7e5902 100644
--- a/xen/drivers/passthrough/Kconfig
+++ b/xen/drivers/passthrough/Kconfig
@@ -51,7 +51,7 @@ config AMD_IOMMU
 
 config INTEL_IOMMU
        bool "Intel VT-d" if EXPERT
-       depends on X86
+       depends on X86 && INTEL_VMX
        default y
        help
          Enables I/O virtualization on platforms that implement the
-- 
2.37.2