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linux-next/drivers/xen/Kconfig
Stefano Stabellini 83862ccfc0 xen/arm,arm64: enable SWIOTLB_XEN
Xen on arm and arm64 needs SWIOTLB_XEN: when running on Xen we need to
program the hardware with mfns rather than pfns for dma addresses.
Remove SWIOTLB_XEN dependency on X86 and PCI and make XEN select
SWIOTLB_XEN on arm and arm64.

At the moment always rely on swiotlb-xen, but when Xen starts supporting
hardware IOMMUs we'll be able to avoid it conditionally on the presence
of an IOMMU on the platform.

Implement xen_create_contiguous_region on arm and arm64: for the moment
we assume that dom0 has been mapped 1:1 (physical addresses == machine
addresses) therefore we don't need to call XENMEM_exchange. Simply
return the physical address as dma address.

Initialize the xen-swiotlb from xen_early_init (before the native
dma_ops are initialized), set xen_dma_ops to &xen_swiotlb_dma_ops.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


Changes in v8:
- assume dom0 is mapped 1:1, no need to call XENMEM_exchange.

Changes in v7:
- call __set_phys_to_machine_multi from xen_create_contiguous_region and
xen_destroy_contiguous_region to update the P2M;
- don't call XENMEM_unpin, it has been removed;
- call XENMEM_exchange instead of XENMEM_exchange_and_pin;
- set nr_exchanged to 0 before calling the hypercall.

Changes in v6:
- introduce and export xen_dma_ops;
- call xen_mm_init from as arch_initcall.

Changes in v4:
- remove redefinition of DMA_ERROR_CODE;
- update the code to use XENMEM_exchange_and_pin and XENMEM_unpin;
- add a note about hardware IOMMU in the commit message.

Changes in v3:
- code style changes;
- warn on XENMEM_put_dma_buf failures.
2013-10-10 13:40:44 +00:00

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menu "Xen driver support"
depends on XEN
config XEN_BALLOON
bool "Xen memory balloon driver"
depends on !ARM
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. If FRONTSWAP is configured,
frontswap-selfshrinking is enabled by default but can be disabled
with the 'tmem.selfshrink=0' kernel boot parameter; and self-ballooning
is enabled by default but can be disabled with the 'tmem.selfballooning=0'
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 trigger 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"
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_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 SWIOTLB_XEN
def_bool y
select SWIOTLB
config XEN_TMEM
tristate
depends on !ARM && !ARM64
default m 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.
config XEN_PRIVCMD
tristate
depends on XEN
default m
config XEN_STUB
bool "Xen stub drivers"
depends on XEN && X86_64 && BROKEN
default n
help
Allow kernel to install stub drivers, to reserve space for Xen drivers,
i.e. memory hotplug and cpu hotplug, and to block native drivers loaded,
so that real Xen drivers can be modular.
To enable Xen features like cpu and memory hotplug, select Y here.
config XEN_ACPI_HOTPLUG_MEMORY
tristate "Xen ACPI memory hotplug"
depends on XEN_DOM0 && XEN_STUB && ACPI
default n
help
This is Xen ACPI memory hotplug.
Currently Xen only support ACPI memory hot-add. If you want
to hot-add memory at runtime (the hot-added memory cannot be
removed until machine stop), select Y/M here, otherwise select N.
config XEN_ACPI_HOTPLUG_CPU
tristate "Xen ACPI cpu hotplug"
depends on XEN_DOM0 && XEN_STUB && ACPI
select ACPI_CONTAINER
default n
help
Xen ACPI cpu enumerating and hotplugging
For hotplugging, currently Xen only support ACPI cpu hotadd.
If you want to hotadd cpu at runtime (the hotadded cpu cannot
be removed until machine stop), select Y/M here.
config XEN_ACPI_PROCESSOR
tristate "Xen ACPI processor"
depends on XEN && 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 itslef 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_DOM0 && X86_64 && X86_MCE
default n
help
Allow kernel fetching MCE error from Xen platform and
converting it into Linux mcelog format for mcelog tools
config XEN_HAVE_PVMMU
bool
endmenu