config X86_64
	def_bool y
	select 64BIT

config X86
	def_bool y
	select ACPI
	select ACPI_LEGACY_TABLES_LOOKUP
	select ACPI_NUMA
	select ALTERNATIVE_CALL
	select ARCH_MAP_DOMAIN_PAGE
	select ARCH_SUPPORTS_INT128
	imply CORE_PARKING
	select GENERIC_BUG_FRAME
	select HAS_ALTERNATIVE
	select HAS_COMPAT
	select HAS_CPUFREQ
	select HAS_DIT
	select HAS_EHCI
	select HAS_EX_TABLE
	select HAS_FAST_MULTIPLY
	select HAS_IOPORTS
	select HAS_KEXEC
	select HAS_NS16550
	select HAS_PASSTHROUGH
	select HAS_PCI
	select HAS_PCI_MSI
	select HAS_SCHED_GRANULARITY
	select HAS_UBSAN
	select HAS_VPCI if HVM
	select NEEDS_LIBELF

config ARCH_DEFCONFIG
	string
	default "arch/x86/configs/x86_64_defconfig"

config CC_HAS_INDIRECT_THUNK
	# GCC >= 8 or Clang >= 6
	def_bool $(cc-option,-mindirect-branch-register) || \
	         $(cc-option,-mretpoline-external-thunk)

config CC_HAS_RETURN_THUNK
	# GCC >= 8 or Clang >= 15
	def_bool $(cc-option,-mfunction-return=thunk-extern)

config HAS_AS_CET_SS
	# binutils >= 2.29 or LLVM >= 6
	def_bool $(as-instr,wrssq %rax$(comma)0;setssbsy)

config HAS_CC_CET_IBT
	# GCC >= 9 and binutils >= 2.29
	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
	def_bool $(cc-option,-fcf-protection=branch -mmanual-endbr -mindirect-branch=thunk-extern) && $(as-instr,endbr64)

menu "Architecture Features"

source "arch/Kconfig"

config PV
	def_bool y
	prompt "PV support"
	---help---
	  Interfaces to support PV domains. These require guest kernel support
	  to run as a PV guest, but don't require any specific hardware support.

	  This option is needed if you want to run PV domains.

	  If unsure, say Y.

config PV32
	bool "Support for 32bit PV guests"
	depends on PV
	default PV_SHIM
	select COMPAT
	---help---
	  The 32bit PV ABI uses Ring1, an area of the x86 architecture which
	  was deprecated and mostly removed in the AMD64 spec.  As a result,
	  it occasionally conflicts with newer x86 hardware features, causing
	  overheads for Xen to maintain backwards compatibility.

	  People may wish to disable 32bit PV guests for attack surface
	  reduction, or performance reasons.  Backwards compatibility can be
	  provided via the PV Shim mechanism.

	  Note that outside of PV Shim, 32-bit PV guests are not security
	  supported anymore.

	  If unsure, use the default setting.

config PV_LINEAR_PT
       bool "Support for PV linear pagetables"
       depends on PV
       default y
       ---help---
         Linear pagetables (also called "recursive pagetables") refers
         to the practice of a guest operating system having pagetable
         entries pointing to other pagetables of the same level (i.e.,
         allowing L2 PTEs to point to other L2 pages).  Some operating
         systems use it as a simple way to consistently map the current
         process's pagetables into its own virtual address space.

         Linux and MiniOS don't use this technique.  NetBSD and Novell
         Netware do; there may be other custom operating systems which
         do.  If you're certain you don't plan on having PV guests
         which use this feature, turning it off can reduce the attack
         surface.

         If unsure, say Y.

config HVM
	bool "HVM support"
	depends on !PV_SHIM_EXCLUSIVE
	default !PV_SHIM
	select COMPAT
	select IOREQ_SERVER
	select MEM_ACCESS_ALWAYS_ON
	---help---
	  Interfaces to support HVM domains.  HVM domains require hardware
	  virtualisation extensions (e.g. Intel VT-x, AMD SVM), but can boot
	  guests which have no specific Xen knowledge.

	  This option is needed if you want to run HVM or PVH domains.

	  If unsure, say Y.

config XEN_SHSTK
	bool "Supervisor Shadow Stacks"
	depends on HAS_AS_CET_SS
	default y
	---help---
	  Control-flow Enforcement Technology (CET) is a set of features in
	  hardware designed to combat Return-oriented Programming (ROP, also
	  call/jump COP/JOP) attacks.  Shadow Stacks are one CET feature
	  designed to provide return address protection.

	  This option arranges for Xen to use CET-SS for its own protection.
	  When CET-SS is active, 32bit PV guests cannot be used.  Backwards
	  compatiblity can be provided via the PV Shim mechanism.

config XEN_IBT
	bool "Supervisor Indirect Branch Tracking"
	depends on HAS_CC_CET_IBT
	default y
	help
	  Control-flow Enforcement Technology (CET) is a set of features in
	  hardware designed to combat Return-oriented Programming (ROP, also
	  call/jump COP/JOP) attacks.  Indirect Branch Tracking is one CET
	  feature designed to provide function pointer protection.

	  This option arranges for Xen to use CET-IBT for its own protection.

config SHADOW_PAGING
	bool "Shadow Paging"
	default !PV_SHIM_EXCLUSIVE
	depends on PV || HVM
	---help---

          Shadow paging is a software alternative to hardware paging support
          (Intel EPT, AMD NPT).

          It is required for:
            * Running HVM guests on hardware lacking hardware paging support
              (First-generation Intel VT-x or AMD SVM).
            * Live migration of PV guests.
            * L1TF sidechannel mitigation for PV guests.

          Under a small number of specific workloads, shadow paging may be
          deliberately used as a performance optimisation.

          If unsure, say Y.

config BIGMEM
	bool "big memory support"
	default n
	---help---
	  Allows Xen to support up to 123Tb of memory.

	  This requires enlarging struct page_info as well as shrinking
	  the always accessible direct mapped memory range.

	  If unsure, say N.

config HVM_FEP
	bool "HVM Forced Emulation Prefix support (UNSUPPORTED)" if UNSUPPORTED
	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 TBOOT
	bool "Xen tboot support (UNSUPPORTED)"
	depends on UNSUPPORTED
	default !PV_SHIM_EXCLUSIVE
	select CRYPTO
	---help---
	  Allows support for Trusted Boot using the Intel(R) Trusted Execution
	  Technology (TXT)

	  If unsure, stay with the default.

choice
	prompt "Alignment of Xen image"
	default XEN_ALIGN_2M if PV_SHIM_EXCLUSIVE
	default XEN_ALIGN_DEFAULT
	---help---
	  Specify alignment for Xen image.

	  If unsure, choose "default".

config XEN_ALIGN_DEFAULT
	bool "Default alignment"
	---help---
	  Pick alignment according to build variants.

	  For EFI build the default alignment is 2M. For ELF build
	  the default alignment is 4K due to syslinux failing to handle
	  the increment of image size induced by 2M alignment.

config XEN_ALIGN_2M
	bool "2M alignment"

endchoice

choice
	prompt "x2APIC Driver default"
	default X2APIC_MIXED
	help
	  Select APIC addressing when x2APIC is enabled.

	  The default mode is mixed which should provide the best aspects
	  of both physical and cluster modes.

config X2APIC_PHYSICAL
	bool "Physical Destination mode"
	help
	  When using this mode APICs are addressed using the Physical
	  Destination mode, which allows using all dynamic vectors on each
	  CPU independently.

	  Physical Destination has the benefit of having more vectors available
	  for external interrupts, but it also makes the delivery of multi
	  destination inter processor interrupts (IPIs) slightly slower than
	  Logical Destination mode.

config X2APIC_CLUSTER
	bool "Cluster Destination mode"
	help
	  When using this mode APICs are addressed using the Cluster Logical
	  Destination mode.

	  Cluster Destination has the benefit of sending IPIs faster since
	  multiple APICs can be targeted as destinations of a single IPI.
	  However the vector space is shared between all CPUs on the cluster,
	  and hence using this mode reduces the number of available vectors
	  when compared to Physical mode.

config X2APIC_MIXED
	bool "Mixed Destination mode"
	help
	  When using this mode APICs are addressed using the Cluster Logical
	  Destination mode for IPIs and Physical mode for external interrupts.

	  Should provide the best of both modes.

endchoice

config GUEST
	bool

config XEN_GUEST
	bool "Xen Guest"
	select GUEST
	---help---
	  Support for Xen detecting when it is running under Xen.

	  If unsure, say N.

config PVH_GUEST
	def_bool y
	prompt "PVH Guest"
	depends on XEN_GUEST
	---help---
	  Support booting using the PVH ABI.

	  If unsure, say Y.

config PV_SHIM
	def_bool y
	prompt "PV Shim"
	depends on PV && XEN_GUEST
	---help---
	  Build Xen with a mode which acts as a shim to allow PV guest to run
	  in an HVM/PVH container. This mode can only be enabled with command
	  line option.

	  If unsure, say Y.

config PV_SHIM_EXCLUSIVE
	bool "PV Shim Exclusive"
	depends on PV_SHIM
	---help---
	  Build Xen in a way which unconditionally assumes PV_SHIM mode.  This
	  option is only intended for use when building a dedicated PV Shim
	  firmware, and will not function correctly in other scenarios.

	  If unsure, say N.

if !PV_SHIM_EXCLUSIVE

config HYPERV_GUEST
	bool "Hyper-V Guest"
	select GUEST
	---help---
	  Support for Xen detecting when it is running under Hyper-V.

	  If unsure, say N.

endif

config MEM_PAGING
	bool "Xen memory paging support (UNSUPPORTED)" if UNSUPPORTED
	depends on HVM

config MEM_SHARING
	bool "Xen memory sharing support (UNSUPPORTED)" if UNSUPPORTED
	depends on HVM

config REQUIRE_NX
	bool "Require NX (No eXecute) support"
	help
	  No-eXecute (also called XD "eXecute Disable" and DEP "Data
	  Execution Prevention") is a security feature designed originally
	  to combat buffer overflow attacks by marking regions of memory
	  which the CPU must not interpret as instructions.

	  The NX feature exists in every 64bit CPU except for some very
	  early Pentium 4 Prescott machines.

	  Enabling this option will improve Xen's security by removing
	  cases where Xen could be tricked into thinking that the feature
	  was unavailable. However, if enabled, Xen will no longer boot on
	  any CPU which is lacking NX support.

endmenu

source "common/Kconfig"

source "drivers/Kconfig"
