linux/drivers/xen/Kconfig
Konrad Rzeszutek Wilk 30edc14bf3 xen/pciback: xen pci backend driver.
This is the host side counterpart to the frontend driver in
drivers/pci/xen-pcifront.c. The PV protocol is also implemented by
frontend drivers in other OSes too, such as the BSDs.

The PV protocol is rather simple. There is page shared with the guest,
which has the 'struct xen_pci_sharedinfo' embossed in it. The backend
has a thread that is kicked every-time the structure is changed and
based on the operation field it performs specific tasks:

 XEN_PCI_OP_conf_[read|write]:
   Read/Write 0xCF8/0xCFC filtered data. (conf_space*.c)
   Based on which field is probed, we either enable/disable the PCI
   device, change power state, read VPD, etc. The major goal of this
   call is to provide a Physical IRQ (PIRQ) to the guest.

   The PIRQ is Xen hypervisor global IRQ value irrespective of the IRQ
   is tied in to the IO-APIC, or is a vector. For GSI type
   interrupts, the PIRQ==GSI holds. For MSI/MSI-X the
   PIRQ value != Linux IRQ number (thought PIRQ==vector).

   Please note, that with Xen, all interrupts (except those level shared ones)
   are injected directly to the guest - there is no host interaction.

 XEN_PCI_OP_[enable|disable]_msi[|x] (pciback_ops.c)
   Enables/disables the MSI/MSI-X capability of the device. These operations
   setup the MSI/MSI-X vectors for the guest and pass them to the frontend.

   When the device is activated, the interrupts are directly injected in the
   guest without involving the host.

 XEN_PCI_OP_aer_[detected|resume|mmio|slotreset]: In case of failure,
  perform the appropriate AER commands on the guest. Right now that is
  a cop-out - we just kill the guest.

Besides implementing those commands, it can also

 - hide a PCI device from the host. When booting up, the user can specify
   xen-pciback.hide=(1:0:0)(BDF..) so that host does not try to use the
   device.

The driver was lifted from linux-2.6.18.hg tree and fixed up
so that it could compile under v3.0. Per suggestion from Jesse Barnes
moved the driver to drivers/xen/xen-pciback.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2011-07-19 20:58:01 -04:00

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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_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_PCIDEV_BACKEND
tristate "Xen PCI-device backend driver"
depends on PCI && X86 && XEN
depends on XEN_BACKEND
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.
choice
prompt "PCI Backend Mode"
depends on XEN_PCIDEV_BACKEND
config XEN_PCIDEV_BACKEND_VPCI
bool "Virtual PCI"
help
This PCI Backend hides the true PCI topology and makes the frontend
think there is a single PCI bus with only the exported devices on it.
For example, a device at 03:05.0 will be re-assigned to 00:00.0. A
second device at 02:1a.1 will be re-assigned to 00:01.1.
config XEN_PCIDEV_BACKEND_PASS
bool "Passthrough"
help
This PCI Backend provides a real view of the PCI topology to the
frontend (for example, a device at 06:01.b will still appear at
06:01.b to the frontend). This is similar to how Xen 2.0.x exposed
PCI devices to its driver domains. This may be required for drivers
which depend on finding their hardward in certain bus/slot
locations.
endchoice
config XEN_PCIDEV_BE_DEBUG
bool "Xen PCI Backend Debugging"
depends on XEN_PCIDEV_BACKEND
default n
help
Allows to observe all of the traffic from the frontend/backend
when reading and writting to the configuration registers.
If in doubt, say no.
endmenu