drivers/xen/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 menu "Xen driver support"
   3         depends on XEN
   4
   5 config XEN_BALLOON
   6         bool "Xen memory balloon driver"
   7         default y
   8         help
   9           The balloon driver allows the Xen domain to request more memory from
  10           the system to expand the domain's memory allocation, or alternatively
  11           return unneeded memory to the system.
  12
  13 config XEN_BALLOON_MEMORY_HOTPLUG
  14         bool "Memory hotplug support for Xen balloon driver"
  15         depends on XEN_BALLOON && MEMORY_HOTPLUG
  16         default y
  17         help
  18           Memory hotplug support for Xen balloon driver allows expanding memory
  19           available for the system above limit declared at system startup.
  20           It is very useful on critical systems which require long
  21           run without rebooting.
  22
  23           It's also very useful for non PV domains to obtain unpopulated physical
  24           memory ranges to use in order to map foreign memory or grants.
  25
  26           Memory could be hotplugged in following steps:
  27
  28             1) target domain: ensure that memory auto online policy is in
  29                effect by checking /sys/devices/system/memory/auto_online_blocks
  30                file (should be 'online').
  31
  32             2) control domain: xl mem-max <target-domain> <maxmem>
  33                where <maxmem> is >= requested memory size,
  34
  35             3) control domain: xl mem-set <target-domain> <memory>
  36                where <memory> is requested memory size; alternatively memory
  37                could be added by writing proper value to
  38                /sys/devices/system/xen_memory/xen_memory0/target or
  39                /sys/devices/system/xen_memory/xen_memory0/target_kb on the
  40                target domain.
  41
  42           Alternatively, if memory auto onlining was not requested at step 1
  43           the newly added memory can be manually onlined in the target domain
  44           by doing the following:
  45
  46                 for i in /sys/devices/system/memory/memory*/state; do \
  47                   [ "`cat "$i"`" = offline ] && echo online > "$i"; done
  48
  49           or by adding the following line to udev rules:
  50
  51           SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
  52
  53 config XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
  54         int "Hotplugged memory limit (in GiB) for a PV guest"
  55         default 512
  56         depends on XEN_HAVE_PVMMU
  57         depends on XEN_BALLOON_MEMORY_HOTPLUG
  58         help
  59           Maxmium amount of memory (in GiB) that a PV guest can be
  60           expanded to when using memory hotplug.
  61
  62           A PV guest can have more memory than this limit if is
  63           started with a larger maximum.
  64
  65           This value is used to allocate enough space in internal
  66           tables needed for physical memory administration.
  67
  68 config XEN_SCRUB_PAGES_DEFAULT
  69         bool "Scrub pages before returning them to system by default"
  70         depends on XEN_BALLOON
  71         default y
  72         help
  73           Scrub pages before returning them to the system for reuse by
  74           other domains.  This makes sure that any confidential data
  75           is not accidentally visible to other domains.  It is more
  76           secure, but slightly less efficient. This can be controlled with
  77           xen_scrub_pages=0 parameter and
  78           /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
  79           This option only sets the default value.
  80
  81           If in doubt, say yes.
  82
  83 config XEN_DEV_EVTCHN
  84         tristate "Xen /dev/xen/evtchn device"
  85         default y
  86         help
  87           The evtchn driver allows a userspace process to trigger event
  88           channels and to receive notification of an event channel
  89           firing.
  90           If in doubt, say yes.
  91
  92 config XEN_BACKEND
  93         bool "Backend driver support"
  94         default XEN_DOM0
  95         help
  96           Support for backend device drivers that provide I/O services
  97           to other virtual machines.
  98
  99 config XENFS
 100         tristate "Xen filesystem"
 101         select XEN_PRIVCMD
 102         default y
 103         help
 104           The xen filesystem provides a way for domains to share
 105           information with each other and with the hypervisor.
 106           For example, by reading and writing the "xenbus" file, guests
 107           may pass arbitrary information to the initial domain.
 108           If in doubt, say yes.
 109
 110 config XEN_COMPAT_XENFS
 111         bool "Create compatibility mount point /proc/xen"
 112         depends on XENFS
 113         default y
 114         help
 115           The old xenstore userspace tools expect to find "xenbus"
 116           under /proc/xen, but "xenbus" is now found at the root of the
 117           xenfs filesystem.  Selecting this causes the kernel to create
 118           the compatibility mount point /proc/xen if it is running on
 119           a xen platform.
 120           If in doubt, say yes.
 121
 122 config XEN_SYS_HYPERVISOR
 123         bool "Create xen entries under /sys/hypervisor"
 124         depends on SYSFS
 125         select SYS_HYPERVISOR
 126         default y
 127         help
 128           Create entries under /sys/hypervisor describing the Xen
 129           hypervisor environment.  When running native or in another
 130           virtual environment, /sys/hypervisor will still be present,
 131           but will have no xen contents.
 132
 133 config XEN_XENBUS_FRONTEND
 134         tristate
 135
 136 config XEN_GNTDEV
 137         tristate "userspace grant access device driver"
 138         depends on XEN
 139         default m
 140         select MMU_NOTIFIER
 141         help
 142           Allows userspace processes to use grants.
 143
 144 config XEN_GNTDEV_DMABUF
 145         bool "Add support for dma-buf grant access device driver extension"
 146         depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC
 147         select DMA_SHARED_BUFFER
 148         help
 149           Allows userspace processes and kernel modules to use Xen backed
 150           dma-buf implementation. With this extension grant references to
 151           the pages of an imported dma-buf can be exported for other domain
 152           use and grant references coming from a foreign domain can be
 153           converted into a local dma-buf for local export.
 154
 155 config XEN_GRANT_DEV_ALLOC
 156         tristate "User-space grant reference allocator driver"
 157         depends on XEN
 158         default m
 159         help
 160           Allows userspace processes to create pages with access granted
 161           to other domains. This can be used to implement frontend drivers
 162           or as part of an inter-domain shared memory channel.
 163
 164 config XEN_GRANT_DMA_ALLOC
 165         bool "Allow allocating DMA capable buffers with grant reference module"
 166         depends on XEN && HAS_DMA
 167         help
 168           Extends grant table module API to allow allocating DMA capable
 169           buffers and mapping foreign grant references on top of it.
 170           The resulting buffer is similar to one allocated by the balloon
 171           driver in that proper memory reservation is made by
 172           ({increase|decrease}_reservation and VA mappings are updated if
 173           needed).
 174           This is useful for sharing foreign buffers with HW drivers which
 175           cannot work with scattered buffers provided by the balloon driver,
 176           but require DMAable memory instead.
 177
 178 config SWIOTLB_XEN
 179         def_bool y
 180         select DMA_OPS
 181         select SWIOTLB
 182
 183 config XEN_PCIDEV_BACKEND
 184         tristate "Xen PCI-device backend driver"
 185         depends on PCI && X86 && XEN
 186         depends on XEN_BACKEND
 187         default m
 188         help
 189           The PCI device backend driver allows the kernel to export arbitrary
 190           PCI devices to other guests. If you select this to be a module, you
 191           will need to make sure no other driver has bound to the device(s)
 192           you want to make visible to other guests.
 193
 194           The parameter "passthrough" allows you specify how you want the PCI
 195           devices to appear in the guest. You can choose the default (0) where
 196           PCI topology starts at 00.00.0, or (1) for passthrough if you want
 197           the PCI devices topology appear the same as in the host.
 198
 199           The "hide" parameter (only applicable if backend driver is compiled
 200           into the kernel) allows you to bind the PCI devices to this module
 201           from the default device drivers. The argument is the list of PCI BDFs:
 202           xen-pciback.hide=(03:00.0)(04:00.0)
 203
 204           If in doubt, say m.
 205
 206 config XEN_PVCALLS_FRONTEND
 207         tristate "XEN PV Calls frontend driver"
 208         depends on INET && XEN
 209         select XEN_XENBUS_FRONTEND
 210         help
 211           Experimental frontend for the Xen PV Calls protocol
 212           (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
 213           sends a small set of POSIX calls to the backend, which
 214           implements them.
 215
 216 config XEN_PVCALLS_BACKEND
 217         bool "XEN PV Calls backend driver"
 218         depends on INET && XEN && XEN_BACKEND
 219         help
 220           Experimental backend for the Xen PV Calls protocol
 221           (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
 222           allows PV Calls frontends to send POSIX calls to the backend,
 223           which implements them.
 224
 225           If in doubt, say n.
 226
 227 config XEN_SCSI_BACKEND
 228         tristate "XEN SCSI backend driver"
 229         depends on XEN && XEN_BACKEND && TARGET_CORE
 230         help
 231           The SCSI backend driver allows the kernel to export its SCSI Devices
 232           to other guests via a high-performance shared-memory interface.
 233           Only needed for systems running as XEN driver domains (e.g. Dom0) and
 234           if guests need generic access to SCSI devices.
 235
 236 config XEN_PRIVCMD
 237         tristate
 238         depends on XEN
 239         default m
 240
 241 config XEN_STUB
 242         bool "Xen stub drivers"
 243         depends on XEN && X86_64 && BROKEN
 244         help
 245           Allow kernel to install stub drivers, to reserve space for Xen drivers,
 246           i.e. memory hotplug and cpu hotplug, and to block native drivers loaded,
 247           so that real Xen drivers can be modular.
 248
 249           To enable Xen features like cpu and memory hotplug, select Y here.
 250
 251 config XEN_ACPI_HOTPLUG_MEMORY
 252         tristate "Xen ACPI memory hotplug"
 253         depends on XEN_DOM0 && XEN_STUB && ACPI
 254         help
 255           This is Xen ACPI memory hotplug.
 256
 257           Currently Xen only support ACPI memory hot-add. If you want
 258           to hot-add memory at runtime (the hot-added memory cannot be
 259           removed until machine stop), select Y/M here, otherwise select N.
 260
 261 config XEN_ACPI_HOTPLUG_CPU
 262         tristate "Xen ACPI cpu hotplug"
 263         depends on XEN_DOM0 && XEN_STUB && ACPI
 264         select ACPI_CONTAINER
 265         help
 266           Xen ACPI cpu enumerating and hotplugging
 267
 268           For hotplugging, currently Xen only support ACPI cpu hotadd.
 269           If you want to hotadd cpu at runtime (the hotadded cpu cannot
 270           be removed until machine stop), select Y/M here.
 271
 272 config XEN_ACPI_PROCESSOR
 273         tristate "Xen ACPI processor"
 274         depends on XEN && XEN_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ
 275         default m
 276         help
 277           This ACPI processor uploads Power Management information to the Xen
 278           hypervisor.
 279
 280           To do that the driver parses the Power Management data and uploads
 281           said information to the Xen hypervisor. Then the Xen hypervisor can
 282           select the proper Cx and Pxx states. It also registers itself as the
 283           SMM so that other drivers (such as ACPI cpufreq scaling driver) will
 284           not load.
 285
 286           To compile this driver as a module, choose M here: the module will be
 287           called xen_acpi_processor  If you do not know what to choose, select
 288           M here. If the CPUFREQ drivers are built in, select Y here.
 289
 290 config XEN_MCE_LOG
 291         bool "Xen platform mcelog"
 292         depends on XEN_DOM0 && X86_MCE
 293         help
 294           Allow kernel fetching MCE error from Xen platform and
 295           converting it into Linux mcelog format for mcelog tools
 296
 297 config XEN_HAVE_PVMMU
 298         bool
 299
 300 config XEN_EFI
 301         def_bool y
 302         depends on (ARM || ARM64 || X86_64) && EFI
 303
 304 config XEN_AUTO_XLATE
 305         def_bool y
 306         depends on ARM || ARM64 || XEN_PVHVM
 307         help
 308           Support for auto-translated physmap guests.
 309
 310 config XEN_ACPI
 311         def_bool y
 312         depends on X86 && ACPI
 313
 314 config XEN_SYMS
 315         bool "Xen symbols"
 316         depends on X86 && XEN_DOM0 && XENFS
 317         default y if KALLSYMS
 318         help
 319           Exports hypervisor symbols (along with their types and addresses) via
 320           /proc/xen/xensyms file, similar to /proc/kallsyms
 321
 322 config XEN_HAVE_VPMU
 323         bool
 324
 325 config XEN_FRONT_PGDIR_SHBUF
 326         tristate
 327
 328 endmenu