drivers/pci/Kconfig - third_party/kernel - Git at Google

 # SPDX-License-Identifier: GPL-2.0
 #
 # PCI configuration
 #

 # select this to offer the PCI prompt
 config HAVE_PCI
 	bool

 # select this to unconditionally force on PCI support
 config FORCE_PCI
 	bool
 	select HAVE_PCI
 	select PCI

 menuconfig PCI
 	bool "PCI support"
 	depends on HAVE_PCI
 	help
 	  This option enables support for the PCI local bus, including
 	  support for PCI-X and the foundations for PCI Express support.
 	  Say 'Y' here unless you know what you are doing.

 if PCI

 config PCI_DOMAINS
 	bool
 	depends on PCI

 config PCI_DOMAINS_GENERIC
 	bool
 	select PCI_DOMAINS

 config PCI_SYSCALL
 	bool

 source "drivers/pci/pcie/Kconfig"

 config PCI_MSI
 	bool "Message Signaled Interrupts (MSI and MSI-X)"
 	select GENERIC_MSI_IRQ
 	help
 	   This allows device drivers to enable MSI (Message Signaled
 	   Interrupts).  Message Signaled Interrupts enable a device to
 	   generate an interrupt using an inbound Memory Write on its
 	   PCI bus instead of asserting a device IRQ pin.

 	   Use of PCI MSI interrupts can be disabled at kernel boot time
 	   by using the 'pci=nomsi' option.  This disables MSI for the
 	   entire system.

 	   If you don't know what to do here, say Y.

 config PCI_MSI_IRQ_DOMAIN
 	def_bool y
 	depends on PCI_MSI
 	select GENERIC_MSI_IRQ_DOMAIN

 config PCI_MSI_ARCH_FALLBACKS
 	bool

 config PCI_QUIRKS
 	default y
 	bool "Enable PCI quirk workarounds" if EXPERT
 	help
 	  This enables workarounds for various PCI chipset bugs/quirks.
 	  Disable this only if your target machine is unaffected by PCI
 	  quirks.

 config PCI_DEBUG
 	bool "PCI Debugging"
 	depends on DEBUG_KERNEL
 	help
 	  Say Y here if you want the PCI core to produce a bunch of debug
 	  messages to the system log.  Select this if you are having a
 	  problem with PCI support and want to see more of what is going on.

 	  When in doubt, say N.

 config PCI_REALLOC_ENABLE_AUTO
 	bool "Enable PCI resource re-allocation detection"
 	depends on PCI_IOV
 	help
 	  Say Y here if you want the PCI core to detect if PCI resource
 	  re-allocation needs to be enabled. You can always use pci=realloc=on
 	  or pci=realloc=off to override it.  It will automatically
 	  re-allocate PCI resources if SR-IOV BARs have not been allocated by
 	  the BIOS.

 	  When in doubt, say N.

 config PCI_STUB
 	tristate "PCI Stub driver"
 	help
 	  Say Y or M here if you want be able to reserve a PCI device
 	  when it is going to be assigned to a guest operating system.

 	  When in doubt, say N.

 config PCI_PF_STUB
 	tristate "PCI PF Stub driver"
 	depends on PCI_IOV
 	help
 	  Say Y or M here if you want to enable support for devices that
 	  require SR-IOV support, while at the same time the PF (Physical
 	  Function) itself is not providing any actual services on the
 	  host itself such as storage or networking.

 	  When in doubt, say N.

 config XEN_PCIDEV_FRONTEND
 	tristate "Xen PCI Frontend"
 	depends on XEN_PV
 	select PCI_XEN
 	select XEN_XENBUS_FRONTEND
 	default y
 	help
 	  The PCI device frontend driver allows the kernel to import arbitrary
 	  PCI devices from a PCI backend to support PCI driver domains.

 config PCI_ATS
 	bool

 config PCI_DOE
 	bool

 config PCI_ECAM
 	bool

 config PCI_LOCKLESS_CONFIG
 	bool

 config PCI_BRIDGE_EMUL
 	bool

 config PCI_IOV
 	bool "PCI IOV support"
 	select PCI_ATS
 	help
 	  I/O Virtualization is a PCI feature supported by some devices
 	  which allows them to create virtual devices which share their
 	  physical resources.

 	  If unsure, say N.

 config PCI_PRI
 	bool "PCI PRI support"
 	select PCI_ATS
 	help
 	  PRI is the PCI Page Request Interface. It allows PCI devices that are
 	  behind an IOMMU to recover from page faults.

 	  If unsure, say N.

 config PCI_PASID
 	bool "PCI PASID support"
 	select PCI_ATS
 	help
 	  Process Address Space Identifiers (PASIDs) can be used by PCI devices
 	  to access more than one IO address space at the same time. To make
 	  use of this feature an IOMMU is required which also supports PASIDs.
 	  Select this option if you have such an IOMMU and want to compile the
 	  driver for it into your kernel.

 	  If unsure, say N.

 config PCI_P2PDMA
 	bool "PCI peer-to-peer transfer support"
 	depends on ZONE_DEVICE
 	#
 	# The need for the scatterlist DMA bus address flag means PCI P2PDMA
 	# requires 64bit
 	#
 	depends on 64BIT
 	select GENERIC_ALLOCATOR
 	help
 	  Enableѕ drivers to do PCI peer-to-peer transactions to and from
 	  BARs that are exposed in other devices that are the part of
 	  the hierarchy where peer-to-peer DMA is guaranteed by the PCI
 	  specification to work (ie. anything below a single PCI bridge).

 	  Many PCIe root complexes do not support P2P transactions and
 	  it's hard to tell which support it at all, so at this time,
 	  P2P DMA transactions must be between devices behind the same root
 	  port.

 	  Enabling this option will reduce the entropy of x86 KASLR memory
 	  regions. For example - on a 46 bit system, the entropy goes down
 	  from 16 bits to 15 bits. The actual reduction in entropy depends
 	  on the physical address bits, on processor features, kernel config
 	  (5 level page table) and physical memory present on the system.

 	  If unsure, say N.

 config PCI_LABEL
 	def_bool y if (DMI || ACPI)
 	select NLS

 config PCI_HYPERV
 	tristate "Hyper-V PCI Frontend"
 	depends on ((X86 && X86_64) || ARM64) && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && SYSFS
 	select PCI_HYPERV_INTERFACE
 	help
 	  The PCI device frontend driver allows the kernel to import arbitrary
 	  PCI devices from a PCI backend to support PCI driver domains.

 choice
 	prompt "PCI Express hierarchy optimization setting"
 	default PCIE_BUS_DEFAULT
 	depends on PCI && EXPERT
 	help
 	  MPS (Max Payload Size) and MRRS (Max Read Request Size) are PCIe
 	  device parameters that affect performance and the ability to
 	  support hotplug and peer-to-peer DMA.

 	  The following choices set the MPS and MRRS optimization strategy
 	  at compile-time.  The choices are the same as those offered for
 	  the kernel command-line parameter 'pci', i.e.,
 	  'pci=pcie_bus_tune_off', 'pci=pcie_bus_safe',
 	  'pci=pcie_bus_perf', and 'pci=pcie_bus_peer2peer'.

 	  This is a compile-time setting and can be overridden by the above
 	  command-line parameters.  If unsure, choose PCIE_BUS_DEFAULT.

 config PCIE_BUS_TUNE_OFF
 	bool "Tune Off"
 	depends on PCI
 	help
 	  Use the BIOS defaults; don't touch MPS at all.  This is the same
 	  as booting with 'pci=pcie_bus_tune_off'.

 config PCIE_BUS_DEFAULT
 	bool "Default"
 	depends on PCI
 	help
 	  Default choice; ensure that the MPS matches upstream bridge.

 config PCIE_BUS_SAFE
 	bool "Safe"
 	depends on PCI
 	help
 	  Use largest MPS that boot-time devices support.  If you have a
 	  closed system with no possibility of adding new devices, this
 	  will use the largest MPS that's supported by all devices.  This
 	  is the same as booting with 'pci=pcie_bus_safe'.

 config PCIE_BUS_PERFORMANCE
 	bool "Performance"
 	depends on PCI
 	help
 	  Use MPS and MRRS for best performance.  Ensure that a given
 	  device's MPS is no larger than its parent MPS, which allows us to
 	  keep all switches/bridges to the max MPS supported by their
 	  parent.  This is the same as booting with 'pci=pcie_bus_perf'.

 config PCIE_BUS_PEER2PEER
 	bool "Peer2peer"
 	depends on PCI
 	help
 	  Set MPS = 128 for all devices.  MPS configuration effected by the
 	  other options could cause the MPS on one root port to be
 	  different than that of the MPS on another, which may cause
 	  hot-added devices or peer-to-peer DMA to fail.  Set MPS to the
 	  smallest possible value (128B) system-wide to avoid these issues.
 	  This is the same as booting with 'pci=pcie_bus_peer2peer'.

 endchoice

 config VGA_ARB
 	bool "VGA Arbitration" if EXPERT
 	default y
 	depends on (PCI && !S390)
 	help
 	  Some "legacy" VGA devices implemented on PCI typically have the same
 	  hard-decoded addresses as they did on ISA. When multiple PCI devices
 	  are accessed at same time they need some kind of coordination. Please
 	  see Documentation/gpu/vgaarbiter.rst for more details. Select this to
 	  enable VGA arbiter.

 config VGA_ARB_MAX_GPUS
 	int "Maximum number of GPUs"
 	default 16
 	depends on VGA_ARB
 	help
 	  Reserves space in the kernel to maintain resource locking for
 	  multiple GPUS.  The overhead for each GPU is very small.

 source "drivers/pci/hotplug/Kconfig"
 source "drivers/pci/controller/Kconfig"
 source "drivers/pci/endpoint/Kconfig"
 source "drivers/pci/switch/Kconfig"

 endif
	# SPDX-License-Identifier: GPL-2.0
	#
	# PCI configuration
	#

	# select this to offer the PCI prompt
	config HAVE_PCI
	bool

	# select this to unconditionally force on PCI support
	config FORCE_PCI
	bool
	select HAVE_PCI
	select PCI

	menuconfig PCI
	bool "PCI support"
	depends on HAVE_PCI
	help
	This option enables support for the PCI local bus, including
	support for PCI-X and the foundations for PCI Express support.
	Say 'Y' here unless you know what you are doing.

	if PCI

	config PCI_DOMAINS
	bool
	depends on PCI

	config PCI_DOMAINS_GENERIC
	bool
	select PCI_DOMAINS

	config PCI_SYSCALL
	bool

	source "drivers/pci/pcie/Kconfig"

	config PCI_MSI
	bool "Message Signaled Interrupts (MSI and MSI-X)"
	select GENERIC_MSI_IRQ
	help
	This allows device drivers to enable MSI (Message Signaled
	Interrupts). Message Signaled Interrupts enable a device to
	generate an interrupt using an inbound Memory Write on its
	PCI bus instead of asserting a device IRQ pin.

	Use of PCI MSI interrupts can be disabled at kernel boot time
	by using the 'pci=nomsi' option. This disables MSI for the
	entire system.

	If you don't know what to do here, say Y.

	config PCI_MSI_IRQ_DOMAIN
	def_bool y
	depends on PCI_MSI
	select GENERIC_MSI_IRQ_DOMAIN

	config PCI_MSI_ARCH_FALLBACKS
	bool

	config PCI_QUIRKS
	default y
	bool "Enable PCI quirk workarounds" if EXPERT
	help
	This enables workarounds for various PCI chipset bugs/quirks.
	Disable this only if your target machine is unaffected by PCI
	quirks.

	config PCI_DEBUG
	bool "PCI Debugging"
	depends on DEBUG_KERNEL
	help
	Say Y here if you want the PCI core to produce a bunch of debug
	messages to the system log. Select this if you are having a
	problem with PCI support and want to see more of what is going on.

	When in doubt, say N.

	config PCI_REALLOC_ENABLE_AUTO
	bool "Enable PCI resource re-allocation detection"
	depends on PCI_IOV
	help
	Say Y here if you want the PCI core to detect if PCI resource
	re-allocation needs to be enabled. You can always use pci=realloc=on
	or pci=realloc=off to override it. It will automatically
	re-allocate PCI resources if SR-IOV BARs have not been allocated by
	the BIOS.

	When in doubt, say N.

	config PCI_STUB
	tristate "PCI Stub driver"
	help
	Say Y or M here if you want be able to reserve a PCI device
	when it is going to be assigned to a guest operating system.

	When in doubt, say N.

	config PCI_PF_STUB
	tristate "PCI PF Stub driver"
	depends on PCI_IOV
	help
	Say Y or M here if you want to enable support for devices that
	require SR-IOV support, while at the same time the PF (Physical
	Function) itself is not providing any actual services on the
	host itself such as storage or networking.

	When in doubt, say N.

	config XEN_PCIDEV_FRONTEND
	tristate "Xen PCI Frontend"
	depends on XEN_PV
	select PCI_XEN
	select XEN_XENBUS_FRONTEND
	default y
	help
	The PCI device frontend driver allows the kernel to import arbitrary
	PCI devices from a PCI backend to support PCI driver domains.

	config PCI_ATS
	bool

	config PCI_DOE
	bool

	config PCI_ECAM
	bool

	config PCI_LOCKLESS_CONFIG
	bool

	config PCI_BRIDGE_EMUL
	bool

	config PCI_IOV
	bool "PCI IOV support"
	select PCI_ATS
	help
	I/O Virtualization is a PCI feature supported by some devices
	which allows them to create virtual devices which share their
	physical resources.

	If unsure, say N.

	config PCI_PRI
	bool "PCI PRI support"
	select PCI_ATS
	help
	PRI is the PCI Page Request Interface. It allows PCI devices that are
	behind an IOMMU to recover from page faults.

	If unsure, say N.

	config PCI_PASID
	bool "PCI PASID support"
	select PCI_ATS
	help
	Process Address Space Identifiers (PASIDs) can be used by PCI devices
	to access more than one IO address space at the same time. To make
	use of this feature an IOMMU is required which also supports PASIDs.
	Select this option if you have such an IOMMU and want to compile the
	driver for it into your kernel.

	If unsure, say N.

	config PCI_P2PDMA
	bool "PCI peer-to-peer transfer support"
	depends on ZONE_DEVICE
	#
	# The need for the scatterlist DMA bus address flag means PCI P2PDMA
	# requires 64bit
	#
	depends on 64BIT
	select GENERIC_ALLOCATOR
	help
	Enableѕ drivers to do PCI peer-to-peer transactions to and from
	BARs that are exposed in other devices that are the part of
	the hierarchy where peer-to-peer DMA is guaranteed by the PCI
	specification to work (ie. anything below a single PCI bridge).

	Many PCIe root complexes do not support P2P transactions and
	it's hard to tell which support it at all, so at this time,
	P2P DMA transactions must be between devices behind the same root
	port.

	Enabling this option will reduce the entropy of x86 KASLR memory
	regions. For example - on a 46 bit system, the entropy goes down
	from 16 bits to 15 bits. The actual reduction in entropy depends
	on the physical address bits, on processor features, kernel config
	(5 level page table) and physical memory present on the system.

	If unsure, say N.

	config PCI_LABEL
	def_bool y if (DMI \|\| ACPI)
	select NLS

	config PCI_HYPERV
	tristate "Hyper-V PCI Frontend"
	depends on ((X86 && X86_64) \|\| ARM64) && HYPERV && PCI_MSI && PCI_MSI_IRQ_DOMAIN && SYSFS
	select PCI_HYPERV_INTERFACE
	help
	The PCI device frontend driver allows the kernel to import arbitrary
	PCI devices from a PCI backend to support PCI driver domains.

	choice
	prompt "PCI Express hierarchy optimization setting"
	default PCIE_BUS_DEFAULT
	depends on PCI && EXPERT
	help
	MPS (Max Payload Size) and MRRS (Max Read Request Size) are PCIe
	device parameters that affect performance and the ability to
	support hotplug and peer-to-peer DMA.

	The following choices set the MPS and MRRS optimization strategy
	at compile-time. The choices are the same as those offered for
	the kernel command-line parameter 'pci', i.e.,
	'pci=pcie_bus_tune_off', 'pci=pcie_bus_safe',
	'pci=pcie_bus_perf', and 'pci=pcie_bus_peer2peer'.

	This is a compile-time setting and can be overridden by the above
	command-line parameters. If unsure, choose PCIE_BUS_DEFAULT.

	config PCIE_BUS_TUNE_OFF
	bool "Tune Off"
	depends on PCI
	help
	Use the BIOS defaults; don't touch MPS at all. This is the same
	as booting with 'pci=pcie_bus_tune_off'.

	config PCIE_BUS_DEFAULT
	bool "Default"
	depends on PCI
	help
	Default choice; ensure that the MPS matches upstream bridge.

	config PCIE_BUS_SAFE
	bool "Safe"
	depends on PCI
	help
	Use largest MPS that boot-time devices support. If you have a
	closed system with no possibility of adding new devices, this
	will use the largest MPS that's supported by all devices. This
	is the same as booting with 'pci=pcie_bus_safe'.

	config PCIE_BUS_PERFORMANCE
	bool "Performance"
	depends on PCI
	help
	Use MPS and MRRS for best performance. Ensure that a given
	device's MPS is no larger than its parent MPS, which allows us to
	keep all switches/bridges to the max MPS supported by their
	parent. This is the same as booting with 'pci=pcie_bus_perf'.

	config PCIE_BUS_PEER2PEER
	bool "Peer2peer"
	depends on PCI
	help
	Set MPS = 128 for all devices. MPS configuration effected by the
	other options could cause the MPS on one root port to be
	different than that of the MPS on another, which may cause
	hot-added devices or peer-to-peer DMA to fail. Set MPS to the
	smallest possible value (128B) system-wide to avoid these issues.
	This is the same as booting with 'pci=pcie_bus_peer2peer'.

	endchoice

	config VGA_ARB
	bool "VGA Arbitration" if EXPERT
	default y
	depends on (PCI && !S390)
	help
	Some "legacy" VGA devices implemented on PCI typically have the same
	hard-decoded addresses as they did on ISA. When multiple PCI devices
	are accessed at same time they need some kind of coordination. Please
	see Documentation/gpu/vgaarbiter.rst for more details. Select this to
	enable VGA arbiter.

	config VGA_ARB_MAX_GPUS
	int "Maximum number of GPUs"
	default 16
	depends on VGA_ARB
	help
	Reserves space in the kernel to maintain resource locking for
	multiple GPUS. The overhead for each GPU is very small.

	source "drivers/pci/hotplug/Kconfig"
	source "drivers/pci/controller/Kconfig"
	source "drivers/pci/endpoint/Kconfig"
	source "drivers/pci/switch/Kconfig"

	endif