1# SPDX-License-Identifier: GPL-2.0-only 2menu "Xen driver support" 3 depends on XEN 4 5config 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 13config 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 28config 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 64config 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 81config 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 96config 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 105config 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 112config 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 123config 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 135config 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 146config XEN_XENBUS_FRONTEND 147 tristate 148 149config 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 157config 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 167config 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 176config 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 190config SWIOTLB_XEN 191 def_bool y 192 select SWIOTLB 193 194config 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 202config 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 225config 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 235config 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 246config 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 255config XEN_PRIVCMD 256 tristate 257 depends on XEN 258 default m 259 260config 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 270config 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 280config 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 291config 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 309config 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 316config XEN_HAVE_PVMMU 317 bool 318 319config XEN_EFI 320 def_bool y 321 depends on (ARM || ARM64 || X86_64) && EFI 322 323config XEN_AUTO_XLATE 324 def_bool y 325 depends on ARM || ARM64 || XEN_PVHVM 326 help 327 Support for auto-translated physmap guests. 328 329config XEN_ACPI 330 def_bool y 331 depends on X86 && ACPI 332 333config 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 341config XEN_HAVE_VPMU 342 bool 343 344config XEN_FRONT_PGDIR_SHBUF 345 tristate 346 347endmenu 348