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 SWIOTLB 183 184config XEN_PCIDEV_BACKEND 185 tristate "Xen PCI-device backend driver" 186 depends on PCI && X86 && XEN 187 depends on XEN_BACKEND 188 default m 189 help 190 The PCI device backend driver allows the kernel to export arbitrary 191 PCI devices to other guests. If you select this to be a module, you 192 will need to make sure no other driver has bound to the device(s) 193 you want to make visible to other guests. 194 195 The parameter "passthrough" allows you specify how you want the PCI 196 devices to appear in the guest. You can choose the default (0) where 197 PCI topology starts at 00.00.0, or (1) for passthrough if you want 198 the PCI devices topology appear the same as in the host. 199 200 The "hide" parameter (only applicable if backend driver is compiled 201 into the kernel) allows you to bind the PCI devices to this module 202 from the default device drivers. The argument is the list of PCI BDFs: 203 xen-pciback.hide=(03:00.0)(04:00.0) 204 205 If in doubt, say m. 206 207config XEN_PVCALLS_FRONTEND 208 tristate "XEN PV Calls frontend driver" 209 depends on INET && XEN 210 select XEN_XENBUS_FRONTEND 211 help 212 Experimental frontend for the Xen PV Calls protocol 213 (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It 214 sends a small set of POSIX calls to the backend, which 215 implements them. 216 217config XEN_PVCALLS_BACKEND 218 bool "XEN PV Calls backend driver" 219 depends on INET && XEN && XEN_BACKEND 220 help 221 Experimental backend for the Xen PV Calls protocol 222 (https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It 223 allows PV Calls frontends to send POSIX calls to the backend, 224 which implements them. 225 226 If in doubt, say n. 227 228config XEN_SCSI_BACKEND 229 tristate "XEN SCSI backend driver" 230 depends on XEN && XEN_BACKEND && TARGET_CORE 231 help 232 The SCSI backend driver allows the kernel to export its SCSI Devices 233 to other guests via a high-performance shared-memory interface. 234 Only needed for systems running as XEN driver domains (e.g. Dom0) and 235 if guests need generic access to SCSI devices. 236 237config XEN_PRIVCMD 238 tristate 239 depends on XEN 240 default m 241 242config XEN_STUB 243 bool "Xen stub drivers" 244 depends on XEN && X86_64 && BROKEN 245 help 246 Allow kernel to install stub drivers, to reserve space for Xen drivers, 247 i.e. memory hotplug and cpu hotplug, and to block native drivers loaded, 248 so that real Xen drivers can be modular. 249 250 To enable Xen features like cpu and memory hotplug, select Y here. 251 252config XEN_ACPI_HOTPLUG_MEMORY 253 tristate "Xen ACPI memory hotplug" 254 depends on XEN_DOM0 && XEN_STUB && ACPI 255 help 256 This is Xen ACPI memory hotplug. 257 258 Currently Xen only support ACPI memory hot-add. If you want 259 to hot-add memory at runtime (the hot-added memory cannot be 260 removed until machine stop), select Y/M here, otherwise select N. 261 262config XEN_ACPI_HOTPLUG_CPU 263 tristate "Xen ACPI cpu hotplug" 264 depends on XEN_DOM0 && XEN_STUB && ACPI 265 select ACPI_CONTAINER 266 help 267 Xen ACPI cpu enumerating and hotplugging 268 269 For hotplugging, currently Xen only support ACPI cpu hotadd. 270 If you want to hotadd cpu at runtime (the hotadded cpu cannot 271 be removed until machine stop), select Y/M here. 272 273config XEN_ACPI_PROCESSOR 274 tristate "Xen ACPI processor" 275 depends on XEN && XEN_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ 276 default m 277 help 278 This ACPI processor uploads Power Management information to the Xen 279 hypervisor. 280 281 To do that the driver parses the Power Management data and uploads 282 said information to the Xen hypervisor. Then the Xen hypervisor can 283 select the proper Cx and Pxx states. It also registers itself as the 284 SMM so that other drivers (such as ACPI cpufreq scaling driver) will 285 not load. 286 287 To compile this driver as a module, choose M here: the module will be 288 called xen_acpi_processor If you do not know what to choose, select 289 M here. If the CPUFREQ drivers are built in, select Y here. 290 291config XEN_MCE_LOG 292 bool "Xen platform mcelog" 293 depends on XEN_DOM0 && X86_MCE 294 help 295 Allow kernel fetching MCE error from Xen platform and 296 converting it into Linux mcelog format for mcelog tools 297 298config XEN_HAVE_PVMMU 299 bool 300 301config XEN_EFI 302 def_bool y 303 depends on (ARM || ARM64 || X86_64) && EFI 304 305config XEN_AUTO_XLATE 306 def_bool y 307 depends on ARM || ARM64 || XEN_PVHVM 308 help 309 Support for auto-translated physmap guests. 310 311config XEN_ACPI 312 def_bool y 313 depends on X86 && ACPI 314 315config XEN_SYMS 316 bool "Xen symbols" 317 depends on X86 && XEN_DOM0 && XENFS 318 default y if KALLSYMS 319 help 320 Exports hypervisor symbols (along with their types and addresses) via 321 /proc/xen/xensyms file, similar to /proc/kallsyms 322 323config XEN_HAVE_VPMU 324 bool 325 326config XEN_FRONT_PGDIR_SHBUF 327 tristate 328 329endmenu 330