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_SELFBALLOONING
  14         bool "Dynamically self-balloon kernel memory to target"
  15         depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP && XEN_TMEM
  16         help
  17           Self-ballooning dynamically balloons available kernel memory driven
  18           by the current usage of anonymous memory ("committed AS") and
  19           controlled by various sysfs-settable parameters.  Configuring
  20           FRONTSWAP is highly recommended; if it is not configured, self-
  21           ballooning is disabled by default. If FRONTSWAP is configured,
  22           frontswap-selfshrinking is enabled by default but can be disabled
  23           with the 'tmem.selfshrink=0' kernel boot parameter; and self-ballooning
  24           is enabled by default but can be disabled with the 'tmem.selfballooning=0'
  25           kernel boot parameter.  Note that systems without a sufficiently
  26           large swap device should not enable self-ballooning.
  27
  28 config XEN_BALLOON_MEMORY_HOTPLUG
  29         bool "Memory hotplug support for Xen balloon driver"
  30         depends on XEN_BALLOON && MEMORY_HOTPLUG
  31         help
  32           Memory hotplug support for Xen balloon driver allows expanding memory
  33           available for the system above limit declared at system startup.
  34           It is very useful on critical systems which require long
  35           run without rebooting.
  36
  37           Memory could be hotplugged in following steps:
  38
  39             1) target domain: ensure that memory auto online policy is in
  40                effect by checking /sys/devices/system/memory/auto_online_blocks
  41                file (should be 'online').
  42
  43             2) control domain: xl mem-max <target-domain> <maxmem>
  44                where <maxmem> is >= requested memory size,
  45
  46             3) control domain: xl mem-set <target-domain> <memory>
  47                where <memory> is requested memory size; alternatively memory
  48                could be added by writing proper value to
  49                /sys/devices/system/xen_memory/xen_memory0/target or
  50                /sys/devices/system/xen_memory/xen_memory0/target_kb on the
  51                target domain.
  52
  53           Alternatively, if memory auto onlining was not requested at step 1
  54           the newly added memory can be manually onlined in the target domain
  55           by doing the following:
  56
  57                 for i in /sys/devices/system/memory/memory*/state; do \
  58                   [ "`cat "$i"`" = offline ] && echo online > "$i"; done
  59
  60           or by adding the following line to udev rules:
  61
  62           SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
  63
  64 config XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
  65         int "Hotplugged memory limit (in GiB) for a PV guest"
  66         default 512 if X86_64
  67         default 4 if X86_32
  68         range 0 64 if X86_32
  69         depends on XEN_HAVE_PVMMU
  70         depends on XEN_BALLOON_MEMORY_HOTPLUG
  71         help
  72           Maxmium amount of memory (in GiB) that a PV guest can be
  73           expanded to when using memory hotplug.
  74
  75           A PV guest can have more memory than this limit if is
  76           started with a larger maximum.
  77
  78           This value is used to allocate enough space in internal
  79           tables needed for physical memory administration.
  80
  81 config XEN_SCRUB_PAGES_DEFAULT
  82         bool "Scrub pages before returning them to system by default"
  83         depends on XEN_BALLOON
  84         default y
  85         help
  86           Scrub pages before returning them to the system for reuse by
  87           other domains.  This makes sure that any confidential data
  88           is not accidentally visible to other domains.  It is more
  89           secure, but slightly less efficient. This can be controlled with
  90           xen_scrub_pages=0 parameter and
  91           /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
  92           This option only sets the default value.
  93
  94           If in doubt, say yes.
  95
  96 config XEN_DEV_EVTCHN
  97         tristate "Xen /dev/xen/evtchn device"
  98         default y
  99         help
 100           The evtchn driver allows a userspace process to trigger event
 101           channels and to receive notification of an event channel
 102           firing.
 103           If in doubt, say yes.
 104
 105 config XEN_BACKEND
 106         bool "Backend driver support"
 107         default XEN_DOM0
 108         help
 109           Support for backend device drivers that provide I/O services
 110           to other virtual machines.
 111
 112 config XENFS
 113         tristate "Xen filesystem"
 114         select XEN_PRIVCMD
 115         default y
 116         help
 117           The xen filesystem provides a way for domains to share
 118           information with each other and with the hypervisor.
 119           For example, by reading and writing the "xenbus" file, guests
 120           may pass arbitrary information to the initial domain.
 121           If in doubt, say yes.
 122
 123 config XEN_COMPAT_XENFS
 124        bool "Create compatibility mount point /proc/xen"
 125        depends on XENFS
 126        default y
 127        help
 128          The old xenstore userspace tools expect to find "xenbus"
 129          under /proc/xen, but "xenbus" is now found at the root of the
 130          xenfs filesystem.  Selecting this causes the kernel to create
 131          the compatibility mount point /proc/xen if it is running on
 132          a xen platform.
 133          If in doubt, say yes.
 134
 135 config XEN_SYS_HYPERVISOR
 136        bool "Create xen entries under /sys/hypervisor"
 137        depends on SYSFS
 138        select SYS_HYPERVISOR
 139        default y
 140        help
 141          Create entries under /sys/hypervisor describing the Xen
 142          hypervisor environment.  When running native or in another
 143          virtual environment, /sys/hypervisor will still be present,
 144          but will have no xen contents.
 145
 146 config XEN_XENBUS_FRONTEND
 147         tristate
 148
 149 config XEN_GNTDEV
 150         tristate "userspace grant access device driver"
 151         depends on XEN
 152         default m
 153         select MMU_NOTIFIER
 154         help
 155           Allows userspace processes to use grants.
 156
 157 config XEN_GNTDEV_DMABUF
 158         bool "Add support for dma-buf grant access device driver extension"
 159         depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC && DMA_SHARED_BUFFER
 160         help
 161           Allows userspace processes and kernel modules to use Xen backed
 162           dma-buf implementation. With this extension grant references to
 163           the pages of an imported dma-buf can be exported for other domain
 164           use and grant references coming from a foreign domain can be
 165           converted into a local dma-buf for local export.
 166
 167 config XEN_GRANT_DEV_ALLOC
 168         tristate "User-space grant reference allocator driver"
 169         depends on XEN
 170         default m
 171         help
 172           Allows userspace processes to create pages with access granted
 173           to other domains. This can be used to implement frontend drivers
 174           or as part of an inter-domain shared memory channel.
 175
 176 config XEN_GRANT_DMA_ALLOC
 177         bool "Allow allocating DMA capable buffers with grant reference module"
 178         depends on XEN && HAS_DMA
 179         help
 180           Extends grant table module API to allow allocating DMA capable
 181           buffers and mapping foreign grant references on top of it.
 182           The resulting buffer is similar to one allocated by the balloon
 183           driver in that proper memory reservation is made by
 184           ({increase|decrease}_reservation and VA mappings are updated if
 185           needed).
 186           This is useful for sharing foreign buffers with HW drivers which
 187           cannot work with scattered buffers provided by the balloon driver,
 188           but require DMAable memory instead.
 189
 190 config SWIOTLB_XEN
 191         def_bool y
 192         select SWIOTLB
 193
 194 config XEN_TMEM
 195         tristate
 196         depends on !ARM && !ARM64
 197         default m if (CLEANCACHE || FRONTSWAP)
 198         help
 199           Shim to interface in-kernel Transcendent Memory hooks
 200           (e.g. cleancache and frontswap) to Xen tmem hypercalls.
 201
 202 config XEN_PCIDEV_BACKEND
 203         tristate "Xen PCI-device backend driver"
 204         depends on PCI && X86 && XEN
 205         depends on XEN_BACKEND
 206         default m
 207         help
 208           The PCI device backend driver allows the kernel to export arbitrary
 209           PCI devices to other guests. If you select this to be a module, you
 210           will need to make sure no other driver has bound to the device(s)
 211           you want to make visible to other guests.
 212
 213           The parameter "passthrough" allows you specify how you want the PCI
 214           devices to appear in the guest. You can choose the default (0) where
 215           PCI topology starts at 00.00.0, or (1) for passthrough if you want
 216           the PCI devices topology appear the same as in the host.
 217
 218           The "hide" parameter (only applicable if backend driver is compiled
 219           into the kernel) allows you to bind the PCI devices to this module
 220           from the default device drivers. The argument is the list of PCI BDFs:
 221           xen-pciback.hide=(03:00.0)(04:00.0)
 222
 223           If in doubt, say m.
 224
 225 config XEN_PVCALLS_FRONTEND
 226         tristate "XEN PV Calls frontend driver"
 227         depends on INET && XEN
 228         select XEN_XENBUS_FRONTEND
 229         help
 230           Experimental frontend for the Xen PV Calls protocol
 231           (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
 232           sends a small set of POSIX calls to the backend, which
 233           implements them.
 234
 235 config XEN_PVCALLS_BACKEND
 236         bool "XEN PV Calls backend driver"
 237         depends on INET && XEN && XEN_BACKEND
 238         help
 239           Experimental backend for the Xen PV Calls protocol
 240           (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
 241           allows PV Calls frontends to send POSIX calls to the backend,
 242           which implements them.
 243
 244           If in doubt, say n.
 245
 246 config XEN_SCSI_BACKEND
 247         tristate "XEN SCSI backend driver"
 248         depends on XEN && XEN_BACKEND && TARGET_CORE
 249         help
 250           The SCSI backend driver allows the kernel to export its SCSI Devices
 251           to other guests via a high-performance shared-memory interface.
 252           Only needed for systems running as XEN driver domains (e.g. Dom0) and
 253           if guests need generic access to SCSI devices.
 254
 255 config XEN_PRIVCMD
 256         tristate
 257         depends on XEN
 258         default m
 259
 260 config XEN_STUB
 261         bool "Xen stub drivers"
 262         depends on XEN && X86_64 && BROKEN
 263         help
 264           Allow kernel to install stub drivers, to reserve space for Xen drivers,
 265           i.e. memory hotplug and cpu hotplug, and to block native drivers loaded,
 266           so that real Xen drivers can be modular.
 267
 268           To enable Xen features like cpu and memory hotplug, select Y here.
 269
 270 config XEN_ACPI_HOTPLUG_MEMORY
 271         tristate "Xen ACPI memory hotplug"
 272         depends on XEN_DOM0 && XEN_STUB && ACPI
 273         help
 274           This is Xen ACPI memory hotplug.
 275
 276           Currently Xen only support ACPI memory hot-add. If you want
 277           to hot-add memory at runtime (the hot-added memory cannot be
 278           removed until machine stop), select Y/M here, otherwise select N.
 279
 280 config XEN_ACPI_HOTPLUG_CPU
 281         tristate "Xen ACPI cpu hotplug"
 282         depends on XEN_DOM0 && XEN_STUB && ACPI
 283         select ACPI_CONTAINER
 284         help
 285           Xen ACPI cpu enumerating and hotplugging
 286
 287           For hotplugging, currently Xen only support ACPI cpu hotadd.
 288           If you want to hotadd cpu at runtime (the hotadded cpu cannot
 289           be removed until machine stop), select Y/M here.
 290
 291 config XEN_ACPI_PROCESSOR
 292         tristate "Xen ACPI processor"
 293         depends on XEN && XEN_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ
 294         default m
 295         help
 296           This ACPI processor uploads Power Management information to the Xen
 297           hypervisor.
 298
 299           To do that the driver parses the Power Management data and uploads
 300           said information to the Xen hypervisor. Then the Xen hypervisor can
 301           select the proper Cx and Pxx states. It also registers itself as the
 302           SMM so that other drivers (such as ACPI cpufreq scaling driver) will
 303           not load.
 304
 305           To compile this driver as a module, choose M here: the module will be
 306           called xen_acpi_processor  If you do not know what to choose, select
 307           M here. If the CPUFREQ drivers are built in, select Y here.
 308
 309 config XEN_MCE_LOG
 310         bool "Xen platform mcelog"
 311         depends on XEN_DOM0 && X86_64 && X86_MCE
 312         help
 313           Allow kernel fetching MCE error from Xen platform and
 314           converting it into Linux mcelog format for mcelog tools
 315
 316 config XEN_HAVE_PVMMU
 317        bool
 318
 319 config XEN_EFI
 320         def_bool y
 321         depends on (ARM || ARM64 || X86_64) && EFI
 322
 323 config XEN_AUTO_XLATE
 324         def_bool y
 325         depends on ARM || ARM64 || XEN_PVHVM
 326         help
 327           Support for auto-translated physmap guests.
 328
 329 config XEN_ACPI
 330         def_bool y
 331         depends on X86 && ACPI
 332
 333 config XEN_SYMS
 334        bool "Xen symbols"
 335        depends on X86 && XEN_DOM0 && XENFS
 336        default y if KALLSYMS
 337        help
 338           Exports hypervisor symbols (along with their types and addresses) via
 339           /proc/xen/xensyms file, similar to /proc/kallsyms
 340
 341 config XEN_HAVE_VPMU
 342        bool
 343
 344 config XEN_FRONT_PGDIR_SHBUF
 345         tristate
 346
 347 endmenu