OpenCloudOS-Kernel/drivers/xen/Kconfig

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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_SELFBALLOONING
bool "Dynamically self-balloon kernel memory to target"
depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP && XEN_TMEM
default n
help
Self-ballooning dynamically balloons available kernel memory driven
by the current usage of anonymous memory ("committed AS") and
controlled by various sysfs-settable parameters. Configuring
FRONTSWAP is highly recommended; if it is not configured, self-
ballooning is disabled by default but can be enabled with the
'selfballooning' kernel boot parameter. If FRONTSWAP is configured,
frontswap-selfshrinking is enabled by default but can be disabled
with the 'noselfshrink' kernel boot parameter; and self-ballooning
is enabled by default but can be disabled with the 'noselfballooning'
kernel boot parameter. Note that systems without a sufficiently
large swap device should not enable self-ballooning.
config XEN_BALLOON_MEMORY_HOTPLUG
bool "Memory hotplug support for Xen balloon driver"
default n
depends on XEN_BALLOON && MEMORY_HOTPLUG
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.
Memory could be hotplugged in following steps:
1) dom0: xl mem-max <domU> <maxmem>
where <maxmem> is >= requested memory size,
2) dom0: xl mem-set <domU> <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 dumU,
3) domU: for i in /sys/devices/system/memory/memory*/state; do \
[ "`cat "$i"`" = offline ] && echo online > "$i"; done
Memory could be onlined automatically on domU by adding following line to udev rules:
SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
In that case step 3 should be omitted.
config XEN_SCRUB_PAGES
bool "Scrub pages before returning them to system"
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. Is it more
secure, but slightly less efficient.
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 triger event
channels and to receive notification of an event channel
firing.
If in doubt, say yes.
config XEN_BACKEND
bool "Backend driver support"
depends on XEN_DOM0
default y
help
Support for backend device drivers that provide I/O services
to other virtual machines.
config XENFS
tristate "Xen filesystem"
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_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_PLATFORM_PCI
tristate "xen platform pci device driver"
depends on XEN_PVHVM && PCI
default m
help
Driver for the Xen PCI Platform device: it is responsible for
initializing xenbus and grant_table when running in a Xen HVM
domain. As a consequence this driver is required to run any Xen PV
frontend on Xen HVM.
config SWIOTLB_XEN
def_bool y
depends on PCI
select SWIOTLB
config XEN_TMEM
bool
default y if (CLEANCACHE || FRONTSWAP)
help
Shim to interface in-kernel Transcendent Memory hooks
(e.g. cleancache and frontswap) to Xen tmem hypercalls.
config XEN_PCIDEV_BACKEND
tristate "Xen PCI-device backend driver"
depends on PCI && X86 && XEN
depends on XEN_BACKEND
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.
endmenu