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menu "Xen driver support"
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bool "Xen memory balloon driver"
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The balloon driver allows the Xen domain to request more memory from
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the system to expand the domain's memory allocation, or alternatively
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return unneeded memory to the system.
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config XEN_SELFBALLOONING
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bool "Dynamically self-balloon kernel memory to target"
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depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP && XEN_TMEM
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Self-ballooning dynamically balloons available kernel memory driven
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by the current usage of anonymous memory ("committed AS") and
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controlled by various sysfs-settable parameters. Configuring
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FRONTSWAP is highly recommended; if it is not configured, self-
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ballooning is disabled by default but can be enabled with the
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'selfballooning' kernel boot parameter. If FRONTSWAP is configured,
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frontswap-selfshrinking is enabled by default but can be disabled
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with the 'noselfshrink' kernel boot parameter; and self-ballooning
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is enabled by default but can be disabled with the 'noselfballooning'
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kernel boot parameter. Note that systems without a sufficiently
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large swap device should not enable self-ballooning.
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config XEN_BALLOON_MEMORY_HOTPLUG
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bool "Memory hotplug support for Xen balloon driver"
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depends on XEN_BALLOON && MEMORY_HOTPLUG
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Memory hotplug support for Xen balloon driver allows expanding memory
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available for the system above limit declared at system startup.
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It is very useful on critical systems which require long
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run without rebooting.
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Memory could be hotplugged in following steps:
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1) dom0: xl mem-max <domU> <maxmem>
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where <maxmem> is >= requested memory size,
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2) dom0: xl mem-set <domU> <memory>
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where <memory> is requested memory size; alternatively memory
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could be added by writing proper value to
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/sys/devices/system/xen_memory/xen_memory0/target or
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/sys/devices/system/xen_memory/xen_memory0/target_kb on dumU,
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3) domU: for i in /sys/devices/system/memory/memory*/state; do \
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[ "`cat "$i"`" = offline ] && echo online > "$i"; done
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Memory could be onlined automatically on domU by adding following line to udev rules:
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SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
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In that case step 3 should be omitted.
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config XEN_SCRUB_PAGES
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bool "Scrub pages before returning them to system"
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depends on XEN_BALLOON
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Scrub pages before returning them to the system for reuse by
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other domains. This makes sure that any confidential data
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is not accidentally visible to other domains. Is it more
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secure, but slightly less efficient.
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tristate "Xen /dev/xen/evtchn device"
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The evtchn driver allows a userspace process to triger event
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channels and to receive notification of an event channel
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bool "Backend driver support"
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Support for backend device drivers that provide I/O services
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to other virtual machines.
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tristate "Xen filesystem"
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The xen filesystem provides a way for domains to share
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information with each other and with the hypervisor.
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For example, by reading and writing the "xenbus" file, guests
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may pass arbitrary information to the initial domain.
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config XEN_COMPAT_XENFS
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bool "Create compatibility mount point /proc/xen"
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The old xenstore userspace tools expect to find "xenbus"
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under /proc/xen, but "xenbus" is now found at the root of the
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xenfs filesystem. Selecting this causes the kernel to create
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the compatibility mount point /proc/xen if it is running on
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If in doubt, say yes.
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config XEN_SYS_HYPERVISOR
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bool "Create xen entries under /sys/hypervisor"
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select SYS_HYPERVISOR
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Create entries under /sys/hypervisor describing the Xen
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hypervisor environment. When running native or in another
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virtual environment, /sys/hypervisor will still be present,
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but will have no xen contents.
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config XEN_XENBUS_FRONTEND
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tristate "userspace grant access device driver"
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Allows userspace processes to use grants.
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config XEN_GRANT_DEV_ALLOC
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tristate "User-space grant reference allocator driver"
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Allows userspace processes to create pages with access granted
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to other domains. This can be used to implement frontend drivers
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or as part of an inter-domain shared memory channel.
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default y if (CLEANCACHE || FRONTSWAP)
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Shim to interface in-kernel Transcendent Memory hooks
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(e.g. cleancache and frontswap) to Xen tmem hypercalls.
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config XEN_PCIDEV_BACKEND
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tristate "Xen PCI-device backend driver"
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depends on PCI && X86 && XEN
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depends on XEN_BACKEND
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The PCI device backend driver allows the kernel to export arbitrary
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PCI devices to other guests. If you select this to be a module, you
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will need to make sure no other driver has bound to the device(s)
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you want to make visible to other guests.
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The parameter "passthrough" allows you specify how you want the PCI
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devices to appear in the guest. You can choose the default (0) where
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PCI topology starts at 00.00.0, or (1) for passthrough if you want
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the PCI devices topology appear the same as in the host.
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The "hide" parameter (only applicable if backend driver is compiled
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into the kernel) allows you to bind the PCI devices to this module
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from the default device drivers. The argument is the list of PCI BDFs:
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xen-pciback.hide=(03:00.0)(04:00.0)