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 if X86_64 56 default 4 if X86_32 57 range 0 64 if X86_32 58 depends on XEN_HAVE_PVMMU 59 depends on XEN_BALLOON_MEMORY_HOTPLUG 60 help 61 Maxmium amount of memory (in GiB) that a PV guest can be 62 expanded to when using memory hotplug. 63 64 A PV guest can have more memory than this limit if is 65 started with a larger maximum. 66 67 This value is used to allocate enough space in internal 68 tables needed for physical memory administration. 69 70config XEN_SCRUB_PAGES_DEFAULT 71 bool "Scrub pages before returning them to system by default" 72 depends on XEN_BALLOON 73 default y 74 help 75 Scrub pages before returning them to the system for reuse by 76 other domains. This makes sure that any confidential data 77 is not accidentally visible to other domains. It is more 78 secure, but slightly less efficient. This can be controlled with 79 xen_scrub_pages=0 parameter and 80 /sys/devices/system/xen_memory/xen_memory0/scrub_pages. 81 This option only sets the default value. 82 83 If in doubt, say yes. 84 85config XEN_DEV_EVTCHN 86 tristate "Xen /dev/xen/evtchn device" 87 default y 88 help 89 The evtchn driver allows a userspace process to trigger event 90 channels and to receive notification of an event channel 91 firing. 92 If in doubt, say yes. 93 94config XEN_BACKEND 95 bool "Backend driver support" 96 default XEN_DOM0 97 help 98 Support for backend device drivers that provide I/O services 99 to other virtual machines. 100 101config XENFS 102 tristate "Xen filesystem" 103 select XEN_PRIVCMD 104 default y 105 help 106 The xen filesystem provides a way for domains to share 107 information with each other and with the hypervisor. 108 For example, by reading and writing the "xenbus" file, guests 109 may pass arbitrary information to the initial domain. 110 If in doubt, say yes. 111 112config XEN_COMPAT_XENFS 113 bool "Create compatibility mount point /proc/xen" 114 depends on XENFS 115 default y 116 help 117 The old xenstore userspace tools expect to find "xenbus" 118 under /proc/xen, but "xenbus" is now found at the root of the 119 xenfs filesystem. Selecting this causes the kernel to create 120 the compatibility mount point /proc/xen if it is running on 121 a xen platform. 122 If in doubt, say yes. 123 124config XEN_SYS_HYPERVISOR 125 bool "Create xen entries under /sys/hypervisor" 126 depends on SYSFS 127 select SYS_HYPERVISOR 128 default y 129 help 130 Create entries under /sys/hypervisor describing the Xen 131 hypervisor environment. When running native or in another 132 virtual environment, /sys/hypervisor will still be present, 133 but will have no xen contents. 134 135config XEN_XENBUS_FRONTEND 136 tristate 137 138config XEN_GNTDEV 139 tristate "userspace grant access device driver" 140 depends on XEN 141 default m 142 select MMU_NOTIFIER 143 help 144 Allows userspace processes to use grants. 145 146config XEN_GNTDEV_DMABUF 147 bool "Add support for dma-buf grant access device driver extension" 148 depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC 149 select DMA_SHARED_BUFFER 150 help 151 Allows userspace processes and kernel modules to use Xen backed 152 dma-buf implementation. With this extension grant references to 153 the pages of an imported dma-buf can be exported for other domain 154 use and grant references coming from a foreign domain can be 155 converted into a local dma-buf for local export. 156 157config XEN_GRANT_DEV_ALLOC 158 tristate "User-space grant reference allocator driver" 159 depends on XEN 160 default m 161 help 162 Allows userspace processes to create pages with access granted 163 to other domains. This can be used to implement frontend drivers 164 or as part of an inter-domain shared memory channel. 165 166config XEN_GRANT_DMA_ALLOC 167 bool "Allow allocating DMA capable buffers with grant reference module" 168 depends on XEN && HAS_DMA 169 help 170 Extends grant table module API to allow allocating DMA capable 171 buffers and mapping foreign grant references on top of it. 172 The resulting buffer is similar to one allocated by the balloon 173 driver in that proper memory reservation is made by 174 ({increase|decrease}_reservation and VA mappings are updated if 175 needed). 176 This is useful for sharing foreign buffers with HW drivers which 177 cannot work with scattered buffers provided by the balloon driver, 178 but require DMAable memory instead. 179 180config SWIOTLB_XEN 181 def_bool y 182 select DMA_OPS 183 select SWIOTLB 184 185config XEN_PCIDEV_BACKEND 186 tristate "Xen PCI-device backend driver" 187 depends on PCI && X86 && XEN 188 depends on XEN_BACKEND 189 default m 190 help 191 The PCI device backend driver allows the kernel to export arbitrary 192 PCI devices to other guests. If you select this to be a module, you 193 will need to make sure no other driver has bound to the device(s) 194 you want to make visible to other guests. 195 196 The parameter "passthrough" allows you specify how you want the PCI 197 devices to appear in the guest. You can choose the default (0) where 198 PCI topology starts at 00.00.0, or (1) for passthrough if you want 199 the PCI devices topology appear the same as in the host. 200 201 The "hide" parameter (only applicable if backend driver is compiled 202 into the kernel) allows you to bind the PCI devices to this module 203 from the default device drivers. The argument is the list of PCI BDFs: 204 xen-pciback.hide=(03:00.0)(04:00.0) 205 206 If in doubt, say m. 207 208config XEN_PVCALLS_FRONTEND 209 tristate "XEN PV Calls frontend driver" 210 depends on INET && XEN 211 select XEN_XENBUS_FRONTEND 212 help 213 Experimental frontend for the Xen PV Calls protocol 214 (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It 215 sends a small set of POSIX calls to the backend, which 216 implements them. 217 218config XEN_PVCALLS_BACKEND 219 bool "XEN PV Calls backend driver" 220 depends on INET && XEN && XEN_BACKEND 221 help 222 Experimental backend for the Xen PV Calls protocol 223 (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It 224 allows PV Calls frontends to send POSIX calls to the backend, 225 which implements them. 226 227 If in doubt, say n. 228 229config XEN_SCSI_BACKEND 230 tristate "XEN SCSI backend driver" 231 depends on XEN && XEN_BACKEND && TARGET_CORE 232 help 233 The SCSI backend driver allows the kernel to export its SCSI Devices 234 to other guests via a high-performance shared-memory interface. 235 Only needed for systems running as XEN driver domains (e.g. Dom0) and 236 if guests need generic access to SCSI devices. 237 238config XEN_PRIVCMD 239 tristate 240 depends on XEN 241 default m 242 243config XEN_STUB 244 bool "Xen stub drivers" 245 depends on XEN && X86_64 && BROKEN 246 help 247 Allow kernel to install stub drivers, to reserve space for Xen drivers, 248 i.e. memory hotplug and cpu hotplug, and to block native drivers loaded, 249 so that real Xen drivers can be modular. 250 251 To enable Xen features like cpu and memory hotplug, select Y here. 252 253config XEN_ACPI_HOTPLUG_MEMORY 254 tristate "Xen ACPI memory hotplug" 255 depends on XEN_DOM0 && XEN_STUB && ACPI 256 help 257 This is Xen ACPI memory hotplug. 258 259 Currently Xen only support ACPI memory hot-add. If you want 260 to hot-add memory at runtime (the hot-added memory cannot be 261 removed until machine stop), select Y/M here, otherwise select N. 262 263config XEN_ACPI_HOTPLUG_CPU 264 tristate "Xen ACPI cpu hotplug" 265 depends on XEN_DOM0 && XEN_STUB && ACPI 266 select ACPI_CONTAINER 267 help 268 Xen ACPI cpu enumerating and hotplugging 269 270 For hotplugging, currently Xen only support ACPI cpu hotadd. 271 If you want to hotadd cpu at runtime (the hotadded cpu cannot 272 be removed until machine stop), select Y/M here. 273 274config XEN_ACPI_PROCESSOR 275 tristate "Xen ACPI processor" 276 depends on XEN && XEN_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ 277 default m 278 help 279 This ACPI processor uploads Power Management information to the Xen 280 hypervisor. 281 282 To do that the driver parses the Power Management data and uploads 283 said information to the Xen hypervisor. Then the Xen hypervisor can 284 select the proper Cx and Pxx states. It also registers itself as the 285 SMM so that other drivers (such as ACPI cpufreq scaling driver) will 286 not load. 287 288 To compile this driver as a module, choose M here: the module will be 289 called xen_acpi_processor If you do not know what to choose, select 290 M here. If the CPUFREQ drivers are built in, select Y here. 291 292config XEN_MCE_LOG 293 bool "Xen platform mcelog" 294 depends on XEN_DOM0 && X86_MCE 295 help 296 Allow kernel fetching MCE error from Xen platform and 297 converting it into Linux mcelog format for mcelog tools 298 299config XEN_HAVE_PVMMU 300 bool 301 302config XEN_EFI 303 def_bool y 304 depends on (ARM || ARM64 || X86_64) && EFI 305 306config XEN_AUTO_XLATE 307 def_bool y 308 depends on ARM || ARM64 || XEN_PVHVM 309 help 310 Support for auto-translated physmap guests. 311 312config XEN_ACPI 313 def_bool y 314 depends on X86 && ACPI 315 316config XEN_SYMS 317 bool "Xen symbols" 318 depends on X86 && XEN_DOM0 && XENFS 319 default y if KALLSYMS 320 help 321 Exports hypervisor symbols (along with their types and addresses) via 322 /proc/xen/xensyms file, similar to /proc/kallsyms 323 324config XEN_HAVE_VPMU 325 bool 326 327config XEN_FRONT_PGDIR_SHBUF 328 tristate 329 330endmenu 331