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_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 53config 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 68config 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 83config 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 92config 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 99config 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 110config 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 122config 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 133config XEN_XENBUS_FRONTEND 134 tristate 135 136config 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 144config 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 155config 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 164config 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 178config SWIOTLB_XEN 179 def_bool y 180 select DMA_OPS 181 select SWIOTLB 182 183config 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 206config 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 216config 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 227config 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 236config XEN_PRIVCMD 237 tristate 238 depends on XEN 239 default m 240 241config 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 251config 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 261config 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 272config 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 290config 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 297config XEN_HAVE_PVMMU 298 bool 299 300config XEN_EFI 301 def_bool y 302 depends on (ARM || ARM64 || X86_64) && EFI 303 304config XEN_AUTO_XLATE 305 def_bool y 306 depends on ARM || ARM64 || XEN_PVHVM 307 help 308 Support for auto-translated physmap guests. 309 310config XEN_ACPI 311 def_bool y 312 depends on X86 && ACPI 313 314config 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 322config XEN_HAVE_VPMU 323 bool 324 325config XEN_FRONT_PGDIR_SHBUF 326 tristate 327 328config XEN_UNPOPULATED_ALLOC 329 bool "Use unpopulated memory ranges for guest mappings" 330 depends on X86 && ZONE_DEVICE 331 default XEN_BACKEND || XEN_GNTDEV || XEN_DOM0 332 help 333 Use unpopulated memory ranges in order to create mappings for guest 334 memory regions, including grant maps and foreign pages. This avoids 335 having to balloon out RAM regions in order to obtain physical memory 336 space to create such mappings. 337 338endmenu 339