# SPDX-License-Identifier: GPL-2.0-only
menu
"Xen driver support"
depends on XEN
config XEN_BALLOON
bool
"Xen memory balloon driver"
default y
help
The balloon driver allows the Xen domain to request more memory
from
the system to expand the domain
's memory allocation, or alternatively
return unneeded memory to the system.
config XEN_BALLOON_MEMORY_HOTPLUG
bool
"Memory hotplug support for Xen balloon driver"
depends on XEN_BALLOON && MEMORY_HOTPLUG
default y
help
Memory hotplug support
for Xen balloon driver allows expanding memory
available
for the system above limit declared at system startup.
It
is very useful on critical systems which require long
run without rebooting.
It
's also very useful for non PV domains to obtain unpopulated physical
memory ranges to use
in order to map foreign memory
or grants.
Memory could be hotplugged
in following steps:
1) target domain: ensure that memory auto online policy
is in
effect by checking /sys/devices/system/memory/auto_online_blocks
file (should be
'online').
2) control domain: xl mem-max <target-domain> <maxmem>
where <maxmem>
is >= requested memory size,
3) control domain: xl mem-set <target-domain> <memory>
where <memory>
is requested memory size; alternatively memory
could be added by writing proper value to
/sys/devices/system/xen_memory/xen_memory0/target
or
/sys/devices/system/xen_memory/xen_memory0/target_kb on the
target domain.
Alternatively,
if memory auto onlining was
not requested at step
1
the newly added memory can be manually onlined
in the target domain
by doing the following:
for i
in /sys/devices/system/memory/memory*/state; do \
[
"`cat "$i
"`" = offline ] && echo online >
"$i"; done
or by adding the following line to udev rules:
SUBSYSTEM==
"memory", ACTION==
"add", RUN+=
"/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
config XEN_MEMORY_HOTPLUG_LIMIT
int
"Hotplugged memory limit (in GiB) for a PV guest"
default
512
depends on XEN_HAVE_PVMMU
depends on MEMORY_HOTPLUG
help
Maximum amount of memory (
in GiB) that a PV guest can be
expanded to when using memory hotplug.
A PV guest can have more memory than this limit
if is
started
with a larger maximum.
This value
is used to allocate enough space
in internal
tables needed
for physical memory administration.
config XEN_SCRUB_PAGES_DEFAULT
bool
"Scrub pages before returning them to system by default"
depends on XEN_BALLOON
default y
help
Scrub pages before returning them to the system
for reuse by
other domains. This makes sure that any confidential data
is not accidentally visible to other domains. It
is more
secure, but slightly less efficient. This can be controlled
with
xen_scrub_pages=
0 parameter
and
/sys/devices/system/xen_memory/xen_memory0/scrub_pages.
This option only sets the default value.
If in doubt, say yes.
config XEN_DEV_EVTCHN
tristate
"Xen /dev/xen/evtchn device"
default y
help
The evtchn driver allows a userspace process to trigger event
channels
and to receive notification of an event channel
firing.
If in doubt, say yes.
config XEN_BACKEND
bool
"Backend driver support"
default XEN_DOM0
help
Support
for backend device drivers that provide I/O services
to other virtual machines.
config XENFS
tristate
"Xen filesystem"
select XEN_PRIVCMD
default y
help
The xen filesystem provides a way
for domains to share
information
with each other
and with the hypervisor.
For example, by reading
and writing the
"xenbus" file, guests
may
pass arbitrary information to the initial domain.
If in doubt, say yes.
config XEN_COMPAT_XENFS
bool
"Create compatibility mount point /proc/xen"
depends on XENFS
default y
help
The old xenstore userspace tools expect to find
"xenbus"
under /proc/xen, but
"xenbus" is now found at the root of the
xenfs filesystem. Selecting this causes the kernel to create
the compatibility mount point /proc/xen
if it
is running on
a xen platform.
If in doubt, say yes.
config XEN_SYS_HYPERVISOR
bool
"Create xen entries under /sys/hypervisor"
depends on SYSFS
select SYS_HYPERVISOR
default y
help
Create entries under /sys/hypervisor describing the Xen
hypervisor environment. When running native
or in another
virtual environment, /sys/hypervisor will still be present,
but will have no xen contents.
config XEN_XENBUS_FRONTEND
tristate
config XEN_GNTDEV
tristate
"userspace grant access device driver"
depends on XEN
default m
select MMU_NOTIFIER
help
Allows userspace processes to use grants.
config XEN_GNTDEV_DMABUF
bool
"Add support for dma-buf grant access device driver extension"
depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC
select DMA_SHARED_BUFFER
help
Allows userspace processes
and kernel modules to use Xen backed
dma-buf implementation.
With this extension grant references to
the pages of an imported dma-buf can be exported
for other domain
use
and grant references coming
from a foreign domain can be
converted into a local dma-buf
for local export.
config XEN_GRANT_DEV_ALLOC
tristate
"User-space grant reference allocator driver"
depends on XEN
default m
help
Allows userspace processes to create pages
with access granted
to other domains. This can be used to implement frontend drivers
or as part of an inter-domain shared memory channel.
config XEN_GRANT_DMA_ALLOC
bool
"Allow allocating DMA capable buffers with grant reference module"
depends on XEN && HAS_DMA
help
Extends grant table module API to allow allocating DMA capable
buffers
and mapping foreign grant references on top of it.
The resulting buffer
is similar to one allocated by the balloon
driver
in that proper memory reservation
is made by
({increase|decrease}_reservation
and VA mappings are updated
if
needed).
This
is useful
for sharing foreign buffers
with HW drivers which
cannot work
with scattered buffers provided by the balloon driver,
but require DMAable memory instead.
config SWIOTLB_XEN
def_bool y
depends on ARCH_HAS_DMA_OPS
depends on XEN_PV || ARM || ARM64
select SWIOTLB
config XEN_PCI_STUB
bool
config XEN_PCIDEV_STUB
tristate
"Xen PCI-device stub driver"
depends on PCI && !X86 && XEN
depends on XEN_BACKEND
select XEN_PCI_STUB
default m
help
The PCI device stub driver provides limited version of the PCI
device backend driver without para-virtualized support
for guests.
If you select this to be a module, you will need to make sure no
other driver has bound to the device(s) you want to make visible to
other guests.
The
"hide" parameter (only applicable
if backend driver
is compiled
into the kernel) allows you to bind the PCI devices to this module
from the default device drivers. The argument
is the list of PCI BDFs:
xen-pciback.hide=(
03:
00.
0)(
04:
00.
0)
If in doubt, say m.
config XEN_PCIDEV_BACKEND
tristate
"Xen PCI-device backend driver"
depends on PCI && X86 && XEN
depends on XEN_BACKEND
select XEN_PCI_STUB
default m
help
The PCI device backend driver allows the kernel to export arbitrary
PCI devices to other guests.
If you select this to be a module, you
will need to make sure no other driver has bound to the device(s)
you want to make visible to other guests.
The parameter
"passthrough" allows you specify how you want the PCI
devices to appear
in the guest. You can choose the default (
0) where
PCI topology starts at
00.
00.
0,
or (
1)
for passthrough
if you want
the PCI devices topology appear the same
as in the host.
The
"hide" parameter (only applicable
if backend driver
is compiled
into the kernel) allows you to bind the PCI devices to this module
from the default device drivers. The argument
is the list of PCI BDFs:
xen-pciback.hide=(
03:
00.
0)(
04:
00.
0)
If in doubt, say m.
config XEN_PVCALLS_FRONTEND
tristate
"XEN PV Calls frontend driver"
depends on INET && XEN
select XEN_XENBUS_FRONTEND
help
Experimental frontend
for the Xen PV Calls protocol
(
https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
sends a small set of POSIX calls to the backend, which
implements them.
config XEN_PVCALLS_BACKEND
tristate
"XEN PV Calls backend driver"
depends on INET && XEN && XEN_BACKEND
help
Experimental backend
for the Xen PV Calls protocol
(
https://xenbits.xen.org/docs/unstable/misc/pvcalls.html). It
allows PV Calls frontends to send POSIX calls to the backend,
which implements them.
If in doubt, say n.
config XEN_SCSI_BACKEND
tristate
"XEN SCSI backend driver"
depends on XEN && XEN_BACKEND && TARGET_CORE
help
The SCSI backend driver allows the kernel to export its SCSI Devices
to other guests via a high-performance shared-memory interface.
Only needed
for systems running
as XEN driver domains (e.g. Dom0)
and
if guests need generic access to SCSI devices.
config XEN_PRIVCMD
tristate
"Xen hypercall passthrough driver"
depends on XEN
default m
help
The hypercall passthrough driver allows privileged user programs to
perform Xen hypercalls. This driver
is normally required
for systems
running
as Dom0 to perform privileged operations, but
in some
disaggregated Xen setups this driver might be needed
for other
domains, too.
config XEN_PRIVCMD_EVENTFD
bool
"Xen Ioeventfd and irqfd support"
depends on XEN_PRIVCMD && XEN_VIRTIO && EVENTFD
help
Using the ioeventfd / irqfd mechanism a virtio backend running
in a
daemon can speed up interrupt delivery
from / to a guest.
config XEN_ACPI_PROCESSOR
tristate
"Xen ACPI processor"
depends on XEN && XEN_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ
default m
help
This ACPI processor uploads Power Management information to the Xen
hypervisor.
To do that the driver parses the Power Management data
and uploads
said information to the Xen hypervisor. Then the Xen hypervisor can
select the proper Cx
and Pxx states. It also registers itself
as the
SMM so that other drivers (such
as ACPI cpufreq scaling driver) will
not load.
To compile this driver
as a module, choose M here: the module will be
called xen_acpi_processor
If you do
not know what to choose, select
M here.
If the CPUFREQ drivers are built
in, select Y here.
config XEN_MCE_LOG
bool
"Xen platform mcelog"
depends on XEN_PV_DOM0 && X86_MCE
help
Allow kernel fetching MCE error
from Xen platform
and
converting it into Linux mcelog format
for mcelog tools
config XEN_HAVE_PVMMU
bool
config XEN_EFI
def_bool y
depends on (ARM || ARM64 || X86_64) && EFI
config XEN_AUTO_XLATE
def_bool y
depends on ARM || ARM64 || XEN_PVHVM
help
Support
for auto-translated physmap guests.
config XEN_ACPI
def_bool y
depends on X86 && ACPI
config XEN_SYMS
bool
"Xen symbols"
depends on X86 && XEN_DOM0 && XENFS
default y
if KALLSYMS
help
Exports hypervisor symbols (along
with their types
and addresses) via
/proc/xen/xensyms file, similar to /proc/kallsyms
config XEN_HAVE_VPMU
bool
config XEN_FRONT_PGDIR_SHBUF
tristate
config XEN_UNPOPULATED_ALLOC
bool
"Use unpopulated memory ranges for guest mappings"
depends on ZONE_DEVICE
default XEN_BACKEND || XEN_GNTDEV || XEN_DOM0
help
Use unpopulated memory ranges
in order to create mappings
for guest
memory regions, including grant maps
and foreign pages. This avoids
having to balloon out RAM regions
in order to obtain physical memory
space to create such mappings.
config XEN_GRANT_DMA_IOMMU
bool
select IOMMU_API
config XEN_GRANT_DMA_OPS
bool
config XEN_VIRTIO
bool
"Xen virtio support"
depends on ARCH_HAS_DMA_OPS
depends on VIRTIO
select XEN_GRANT_DMA_OPS
select XEN_GRANT_DMA_IOMMU
if OF
help
Enable virtio support
for running
as Xen guest. Depending on the
guest type this will require special support on the backend side
(qemu
or kernel, depending on the virtio device types used).
If in doubt, say n.
config XEN_VIRTIO_FORCE_GRANT
bool
"Require Xen virtio support to use grants"
depends on XEN_VIRTIO
help
Require virtio
for Xen guests to use grant mappings.
This will avoid the need to give the backend the right to map all
of the guest memory. This will need support on the backend side
(e.g. qemu
or kernel, depending on the virtio device types used).
endmenu
