# SPDX-License-Identifier: GPL-2.0-only menu "Xen driver support" depends on XEN config XEN_BALLOON bool "Xen memory balloon driver" default y help The balloon driver allows the Xen domain to request more memory from the system to expand the domain's memory allocation, or alternatively return unneeded memory to the system. config XEN_BALLOON_MEMORY_HOTPLUG bool "Memory hotplug support for Xen balloon driver" depends on XEN_BALLOON && MEMORY_HOTPLUG default y help Memory hotplug support for Xen balloon driver allows expanding memory available for the system above limit declared at system startup. It is very useful on critical systems which require long run without rebooting. It's also very useful for non PV domains to obtain unpopulated physical memory ranges to use in order to map foreign memory or grants. Memory could be hotplugged in following steps: 1) target domain: ensure that memory auto online policy is in effect by checking /sys/devices/system/memory/auto_online_blocks file (should be 'online'). 2) control domain: xl mem-max <target-domain> <maxmem> where <maxmem> is >= requested memory size, 3) control domain: xl mem-set <target-domain> <memory> where <memory> is requested memory size; alternatively memory could be added by writing proper value to /sys/devices/system/xen_memory/xen_memory0/target or /sys/devices/system/xen_memory/xen_memory0/target_kb on the target domain. Alternatively, if memory auto onlining was not requested at step 1 the newly added memory can be manually onlined in the target domain by doing the following: for i in /sys/devices/system/memory/memory*/state; do \ [ "`cat "$i"`" = offline ] && echo online > "$i"; done or by adding the following line to udev rules: SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'" config XEN_MEMORY_HOTPLUG_LIMIT int "Hotplugged memory limit (in GiB) for a PV guest" default 512 depends on XEN_HAVE_PVMMU depends on MEMORY_HOTPLUG help Maximum amount of memory (in GiB) that a PV guest can be expanded to when using memory hotplug. A PV guest can have more memory than this limit if is started with a larger maximum. This value is used to allocate enough space in internal tables needed for physical memory administration. config XEN_SCRUB_PAGES_DEFAULT bool "Scrub pages before returning them to system by default" depends on XEN_BALLOON default y help Scrub pages before returning them to the system for reuse by other domains. This makes sure that any confidential data is not accidentally visible to other domains. It is more secure, but slightly less efficient. This can be controlled with xen_scrub_pages=0 parameter and /sys/devices/system/xen_memory/xen_memory0/scrub_pages. This option only sets the default value. If in doubt, say yes. config XEN_DEV_EVTCHN tristate "Xen /dev/xen/evtchn device" default y help The evtchn driver allows a userspace process to trigger event channels and to receive notification of an event channel firing. If in doubt, say yes. config XEN_BACKEND bool "Backend driver support" default XEN_DOM0 help Support for backend device drivers that provide I/O services to other virtual machines. config XENFS tristate "Xen filesystem" select XEN_PRIVCMD default y help The xen filesystem provides a way for domains to share information with each other and with the hypervisor. For example, by reading and writing the "xenbus" file, guests may pass arbitrary information to the initial domain. If in doubt, say yes. config XEN_COMPAT_XENFS bool "Create compatibility mount point /proc/xen" depends on XENFS default y help The old xenstore userspace tools expect to find "xenbus" under /proc/xen, but "xenbus" is now found at the root of the xenfs filesystem. Selecting this causes the kernel to create the compatibility mount point /proc/xen if it is running on a xen platform. If in doubt, say yes. config XEN_SYS_HYPERVISOR bool "Create xen entries under /sys/hypervisor" depends on SYSFS select SYS_HYPERVISOR default y help Create entries under /sys/hypervisor describing the Xen hypervisor environment. When running native or in another virtual environment, /sys/hypervisor will still be present, but will have no xen contents. config XEN_XENBUS_FRONTEND tristate config XEN_GNTDEV tristate "userspace grant access device driver" depends on XEN default m select MMU_NOTIFIER help Allows userspace processes to use grants. config XEN_GNTDEV_DMABUF bool "Add support for dma-buf grant access device driver extension" depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC select DMA_SHARED_BUFFER help Allows userspace processes and kernel modules to use Xen backed dma-buf implementation. With this extension grant references to the pages of an imported dma-buf can be exported for other domain use and grant references coming from a foreign domain can be converted into a local dma-buf for local export. config XEN_GRANT_DEV_ALLOC tristate "User-space grant reference allocator driver" depends on XEN default m help Allows userspace processes to create pages with access granted to other domains. This can be used to implement frontend drivers or as part of an inter-domain shared memory channel. config XEN_GRANT_DMA_ALLOC bool "Allow allocating DMA capable buffers with grant reference module" depends on XEN && HAS_DMA help Extends grant table module API to allow allocating DMA capable buffers and mapping foreign grant references on top of it. The resulting buffer is similar to one allocated by the balloon driver in that proper memory reservation is made by ({increase|decrease}_reservation and VA mappings are updated if needed). This is useful for sharing foreign buffers with HW drivers which cannot work with scattered buffers provided by the balloon driver, but require DMAable memory instead. config SWIOTLB_XEN def_bool y depends on XEN_PV || ARM || ARM64 select DMA_OPS select SWIOTLB config XEN_PCI_STUB bool config XEN_PCIDEV_STUB tristate "Xen PCI-device stub driver" depends on PCI && !X86 && XEN depends on XEN_BACKEND select XEN_PCI_STUB default m help The PCI device stub driver provides limited version of the PCI device backend driver without para-virtualized support for guests. If you select this to be a module, you will need to make sure no other driver has bound to the device(s) you want to make visible to other guests. The "hide" parameter (only applicable if backend driver is compiled into the kernel) allows you to bind the PCI devices to this module from the default device drivers. The argument is the list of PCI BDFs: xen-pciback.hide=(03:00.0)(04:00.0) If in doubt, say m. config XEN_PCIDEV_BACKEND tristate "Xen PCI-device backend driver" depends on PCI && X86 && XEN depends on XEN_BACKEND select XEN_PCI_STUB default m help The PCI device backend driver allows the kernel to export arbitrary PCI devices to other guests. If you select this to be a module, you will need to make sure no other driver has bound to the device(s) you want to make visible to other guests. The parameter "passthrough" allows you specify how you want the PCI devices to appear in the guest. You can choose the default (0) where PCI topology starts at 00.00.0, or (1) for passthrough if you want the PCI devices topology appear the same as in the host. The "hide" parameter (only applicable if backend driver is compiled into the kernel) allows you to bind the PCI devices to this module from the default device drivers. The argument is the list of PCI BDFs: xen-pciback.hide=(03:00.0)(04:00.0) If in doubt, say m. config XEN_PVCALLS_FRONTEND tristate "XEN PV Calls frontend driver" depends on INET && XEN select XEN_XENBUS_FRONTEND help Experimental frontend for the Xen PV Calls protocol (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It sends a small set of POSIX calls to the backend, which implements them. config XEN_PVCALLS_BACKEND tristate "XEN PV Calls backend driver" depends on INET && XEN && XEN_BACKEND help Experimental backend for the Xen PV Calls protocol (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It allows PV Calls frontends to send POSIX calls to the backend, which implements them. If in doubt, say n. config XEN_SCSI_BACKEND tristate "XEN SCSI backend driver" depends on XEN && XEN_BACKEND && TARGET_CORE help The SCSI backend driver allows the kernel to export its SCSI Devices to other guests via a high-performance shared-memory interface. Only needed for systems running as XEN driver domains (e.g. Dom0) and if guests need generic access to SCSI devices. config XEN_PRIVCMD tristate "Xen hypercall passthrough driver" depends on XEN default m help The hypercall passthrough driver allows privileged user programs to perform Xen hypercalls. This driver is normally required for systems running as Dom0 to perform privileged operations, but in some disaggregated Xen setups this driver might be needed for other domains, too. config XEN_ACPI_PROCESSOR tristate "Xen ACPI processor" depends on XEN && XEN_PV_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ default m help This ACPI processor uploads Power Management information to the Xen hypervisor. To do that the driver parses the Power Management data and uploads said information to the Xen hypervisor. Then the Xen hypervisor can select the proper Cx and Pxx states. It also registers itself as the SMM so that other drivers (such as ACPI cpufreq scaling driver) will not load. To compile this driver as a module, choose M here: the module will be called xen_acpi_processor If you do not know what to choose, select M here. If the CPUFREQ drivers are built in, select Y here. config XEN_MCE_LOG bool "Xen platform mcelog" depends on XEN_PV_DOM0 && X86_MCE help Allow kernel fetching MCE error from Xen platform and converting it into Linux mcelog format for mcelog tools config XEN_HAVE_PVMMU bool config XEN_EFI def_bool y depends on (ARM || ARM64 || X86_64) && EFI config XEN_AUTO_XLATE def_bool y depends on ARM || ARM64 || XEN_PVHVM help Support for auto-translated physmap guests. config XEN_ACPI def_bool y depends on X86 && ACPI config XEN_SYMS bool "Xen symbols" depends on X86 && XEN_DOM0 && XENFS default y if KALLSYMS help Exports hypervisor symbols (along with their types and addresses) via /proc/xen/xensyms file, similar to /proc/kallsyms config XEN_HAVE_VPMU bool config XEN_FRONT_PGDIR_SHBUF tristate config XEN_UNPOPULATED_ALLOC bool "Use unpopulated memory ranges for guest mappings" depends on ZONE_DEVICE default XEN_BACKEND || XEN_GNTDEV || XEN_DOM0 help Use unpopulated memory ranges in order to create mappings for guest memory regions, including grant maps and foreign pages. This avoids having to balloon out RAM regions in order to obtain physical memory space to create such mappings. config XEN_GRANT_DMA_IOMMU bool select IOMMU_API config XEN_GRANT_DMA_OPS bool select DMA_OPS config XEN_VIRTIO bool "Xen virtio support" depends on VIRTIO select XEN_GRANT_DMA_OPS select XEN_GRANT_DMA_IOMMU if OF help Enable virtio support for running as Xen guest. Depending on the guest type this will require special support on the backend side (qemu or kernel, depending on the virtio device types used). If in doubt, say n. config XEN_VIRTIO_FORCE_GRANT bool "Require Xen virtio support to use grants" depends on XEN_VIRTIO help Require virtio for Xen guests to use grant mappings. This will avoid the need to give the backend the right to map all of the guest memory. This will need support on the backend side (e.g. qemu or kernel, depending on the virtio device types used). endmenu