Devices should depend on virtio, not select it.  It's supposed to be
selected by the particular driver, e.g. VIRTIO_PCI.
Make balloon depend on VIRTIO and EXPERIMENTAL
(to match description).
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This patch adds an option to instantiate guest virtio-mmio devices
basing on a kernel command line (or module) parameter, for example:

	virtio_mmio.devices=0x100@0x100b0000:48
Signed-off-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Fix this compile error on s390:

  CC [M]  drivers/virtio/virtio_mmio.o
drivers/virtio/virtio_mmio.c: In function 'vm_get_features':
drivers/virtio/virtio_mmio.c:107:2: error: implicit declaration of function 'writel'

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This patch, based on virtio PCI driver, adds support for memory
mapped (platform) virtio device. This should allow environments
like qemu to use virtio-based block & network devices even on
platforms without PCI support.

One can define and register a platform device which resources
will describe memory mapped control registers and "mailbox"
interrupt. Such device can be also instantiated using the Device
Tree node with compatible property equal "virtio,mmio".

Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Michael S.Tsirkin <mst@redhat.com>
Signed-off-by: NPawel Moll <pawel.moll@arm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

virtio has been so far used only in the context of virtualization,
and the virtio Kconfig was sourced directly by the relevant arch
Kconfigs when VIRTUALIZATION was selected.

Now that we start using virtio for inter-processor communications,
we need to source the virtio Kconfig outside of the virtualization
scope too.

Moreover, some architectures might use virtio for both virtualization
and inter-processor communications, so directly sourcing virtio
might yield unexpected results due to conflicting selections.

The simple solution offered by this patch is to always source virtio's
Kconfig in drivers/Kconfig, and remove it from the appropriate arch
Kconfigs. Additionally, a virtio menu entry has been added so virtio
drivers don't show up in the general drivers menu.

This way anyone can use virtio, though it's arguably less accessible
(and neat!) for virtualization users now.

Note: some architectures (mips and sh) seem to have a VIRTUALIZATION
menu merely for sourcing virtio's Kconfig, so that menu is removed too.
Signed-off-by: NOhad Ben-Cohen <ohad@wizery.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

After discussions with Anthony Liguori, it seems that the virtio
balloon can be made even simpler.  Here's my attempt.

The device configuration tells the driver how much memory it should
take from the guest (ie. balloon size).  The guest feeds the page
numbers it has taken via one virtqueue.

A second virtqueue feeds the page numbers the driver wants back: if
the device has the VIRTIO_BALLOON_F_MUST_TELL_HOST bit, then this
queue is compulsory, otherwise it's advisory (and the guest can simply
fault the pages back in).

This driver can be enhanced later to deflate the balloon via a
shrinker, oom callback or we could even go for a complete set of
in-guest regulators.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This is a PCI device that implements a transport for virtio.  It allows virtio
devices to be used by QEMU based VMMs like KVM or Xen.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This is needed for the virtio PCI device to be compiled as a module.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

These helper routines supply most of the virtqueue_ops for hypervisors
which want to use a ring for virtio.  Unlike the previous lguest
implementation:

1) The rings are variable sized (2^n-1 elements).
2) They have an unfortunate limit of 65535 bytes per sg element.
3) The page numbers are always 64 bit (PAE anyone?)
4) They no longer place used[] on a separate page, just a separate
   cacheline.
5) We do a modulo on a variable.  We could be tricky if we cared.
6) Interrupts and notifies are suppressed using flags within the rings.

Users need only get the ring pages and provide a notify hook (KVM
wants the guest to allocate the rings, lguest does it sanely).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dor Laor <dor.laor@qumranet.com>

This attempts to implement a "virtual I/O" layer which should allow
common drivers to be efficiently used across most virtual I/O
mechanisms.  It will no-doubt need further enhancement.

The virtio drivers add buffers to virtio queues; as the buffers are consumed
the driver "interrupt" callbacks are invoked.

There is also a generic implementation of config space which drivers can query
to get setup information from the host.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dor Laor <dor.laor@qumranet.com>
Cc: Arnd Bergmann <arnd@arndb.de>