xen: privcmd: Add support for ioeventfd

Virtio guests send VIRTIO_MMIO_QUEUE_NOTIFY notification when they need
to notify the backend of an update to the status of the virtqueue. The
backend or another entity, polls the MMIO address for updates to know
when the notification is sent.

It works well if the backend does this polling by itself. But as we move
towards generic backend implementations, we end up implementing this in
a separate user-space program.

Generally, the Virtio backends are implemented to work with the Eventfd
based mechanism. In order to make such backends work with Xen, another
software layer needs to do the polling and send an event via eventfd to
the backend once the notification from guest is received. This results
in an extra context switch.

This is not a new problem in Linux though. It is present with other
hypervisors like KVM, etc. as well. The generic solution implemented in
the kernel for them is to provide an IOCTL call to pass the address to
poll and eventfd, which lets the kernel take care of polling and raise
an event on the eventfd, instead of handling this in user space (which
involves an extra context switch).

This patch adds similar support for xen.

Inspired by existing implementations for KVM, etc..

This also copies ioreq.h header file (only struct ioreq and related
macros) from Xen's source tree (Top commit 5d84f07fe6bf ("xen/pci: drop
remaining uses of bool_t")).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/b20d83efba6453037d0c099912813c79c81f7714.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: privcmd: Add support for irqfd

Xen provides support for injecting interrupts to the guests via the
HYPERVISOR_dm_op() hypercall. The same is used by the Virtio based
device backend implementations, in an inefficient manner currently.

Generally, the Virtio backends are implemented to work with the Eventfd
based mechanism. In order to make such backends work with Xen, another
software layer needs to poll the Eventfds and raise an interrupt to the
guest using the Xen based mechanism. This results in an extra context
switch.

This is not a new problem in Linux though. It is present with other
hypervisors like KVM, etc. as well. The generic solution implemented in
the kernel for them is to provide an IOCTL call to pass the interrupt
details and eventfd, which lets the kernel take care of polling the
eventfd and raising of the interrupt, instead of handling this in user
space (which involves an extra context switch).

This patch adds support to inject a specific interrupt to guest using
the eventfd mechanism, by preventing the extra context switch.

Inspired by existing implementations for KVM, etc..

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/8e724ac1f50c2bc1eb8da9b3ff6166f1372570aa.1692697321.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: Kconfig: Fix spelling mistake "Maxmium" -> "Maximum"

There is a spelling mistake in a Kconfig description. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20221007203500.2756787-1-colin.i.king@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: don't require virtio with grants for non-PV guests

Commit fa1f57421e0b ("xen/virtio: Enable restricted memory access using
Xen grant mappings") introduced a new requirement for using virtio
devices: the backend now needs to support the VIRTIO_F_ACCESS_PLATFORM
feature.

This is an undue requirement for non-PV guests, as those can be operated
with existing backends without any problem, as long as those backends
are running in dom0.

Per default allow virtio devices without grant support for non-PV
guests.

On Arm require VIRTIO_F_ACCESS_PLATFORM for devices having been listed
in the device tree to use grants.

Add a new config item to always force use of grants for virtio.

Fixes: fa1f57421e0b ("xen/virtio: Enable restricted memory access using Xen grant mappings")
Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 guest using Xen
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220622063838.8854-4-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices

Use the presence of "iommus" property pointed to the IOMMU node with
recently introduced "xen,grant-dma" compatible as a clear indicator
of enabling Xen grant mappings scheme for that device and read the ID
of Xen domain where the corresponding backend is running. The domid
(domain ID) is used as an argument to the Xen grant mapping APIs.

To avoid the deferred probe timeout which takes place after reusing
generic IOMMU device tree bindings (because the IOMMU device never
becomes available) enable recently introduced stub IOMMU driver by
selecting XEN_GRANT_DMA_IOMMU.

Also introduce xen_is_grant_dma_device() to check whether xen-grant
DMA ops need to be set for a passed device.

Remove the hardcoded domid 0 in xen_grant_setup_dma_ops().

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/1654197833-25362-8-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/grant-dma-iommu: Introduce stub IOMMU driver

In order to reuse generic IOMMU device tree bindings by Xen grant
DMA-mapping layer we need to add this stub driver from a fw_devlink
perspective (grant-dma-ops cannot be converted into the proper
IOMMU driver).

Otherwise, just reusing IOMMU bindings (without having a corresponding
driver) leads to the deferred probe timeout afterwards, because
the IOMMU device never becomes available.

This stub driver does nothing except registering empty iommu_ops,
the upper layer "of_iommu" will treat this as NO_IOMMU condition
and won't return -EPROBE_DEFER.

As this driver is quite different from the most hardware IOMMU
implementations and only needed in Xen guests, place it in drivers/xen
directory. The subsequent commit will make use of it.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/1654197833-25362-7-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/virtio: Enable restricted memory access using Xen grant mappings

In order to support virtio in Xen guests add a config option XEN_VIRTIO
enabling the user to specify whether in all Xen guests virtio should
be able to access memory via Xen grant mappings only on the host side.

Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest
initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/1654197833-25362-5-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/grant-dma-ops: Add option to restrict memory access under Xen

Introduce Xen grant DMA-mapping layer which contains special DMA-mapping
routines for providing grant references as DMA addresses to be used by
frontends (e.g. virtio) in Xen guests.

Add the needed functionality by providing a special set of DMA ops
handling the needed grant operations for the I/O pages.

The subsequent commit will introduce the use case for xen-grant DMA ops
layer to enable using virtio devices in Xen guests in a safe manner.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/1654197833-25362-4-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>

arm/xen: Read extended regions from DT and init Xen resource

This patch implements arch_xen_unpopulated_init() on Arm where
the extended regions (if any) are gathered from DT and inserted
into specific Xen resource to be used as unused address space
for Xen scratch pages by unpopulated-alloc code.

The extended region (safe range) is a region of guest physical
address space which is unused and could be safely used to create
grant/foreign mappings instead of wasting real RAM pages from
the domain memory for establishing these mappings.

The extended regions are chosen by the hypervisor at the domain
creation time and advertised to it via "reg" property under
hypervisor node in the guest device-tree. As region 0 is reserved
for grant table space (always present), the indexes for extended
regions are 1...N.

If arch_xen_unpopulated_init() fails for some reason the default
behaviour will be restored (allocate xenballooned pages).

This patch also removes XEN_UNPOPULATED_ALLOC dependency on x86.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/1639080336-26573-6-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/privcmd: make option visible in Kconfig

This configuration option provides a misc device as an API to userspace.
Make this API usable without having to select the module as a transitive
dependency.

This also fixes an issue where localyesconfig would select
CONFIG_XEN_PRIVCMD=m because it was not visible and defaulted to
building as module.

[boris: clarified help message per Jan's suggestion]

Based-on-patch-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211116143323.18866-1-jgross@suse.com
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen-pciback: allow compiling on other archs than x86

Xen-pciback driver was designed to be built for x86 only. But it
can also be used by other architectures, e.g. Arm.

Currently PCI backend implements multiple functionalities at a time,
such as:
1. It is used as a database for assignable PCI devices, e.g. xl
pci-assignable-{add|remove|list} manipulates that list. So, whenever
the toolstack needs to know which PCI devices can be passed through
it reads that from the relevant sysfs entries of the pciback.
2. It is used to hold the unbound PCI devices list, e.g. when passing
through a PCI device it needs to be unbound from the relevant device
driver and bound to pciback (strictly speaking it is not required
that the device is bound to pciback, but pciback is again used as a
database of the passed through PCI devices, so we can re-bind the
devices back to their original drivers when guest domain shuts down)
3. Device reset for the devices being passed through
4. Para-virtualised use-cases support

The para-virtualised part of the driver is not always needed as some
architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
model for PCI device passthrough.

For such use-cases make the very first step in splitting the
xen-pciback driver into two parts: Xen PCI stub and PCI PV backend
drivers.

For that add new configuration options CONFIG_XEN_PCI_STUB and
CONFIG_XEN_PCIDEV_STUB, so the driver can be limited in its
functionality, e.g. no support for para-virtualised scenario.
x86 platform will continue using CONFIG_XEN_PCIDEV_BACKEND for the
fully featured backend driver.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211028143620.144936-1-andr2000@gmail.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen/x86: allow PVH Dom0 without XEN_PV=y

Decouple XEN_DOM0 from XEN_PV, converting some existing uses of XEN_DOM0
to a new XEN_PV_DOM0. (I'm not convinced all are really / should really
be PV-specific, but for starters I've tried to be conservative.)

For PVH Dom0 the hypervisor populates MADT with only x2APIC entries, so
without x2APIC support enabled in the kernel things aren't going to work
very well. (As opposed, DomU-s would only ever see LAPIC entries in MADT
as of now.) Note that this then requires PVH Dom0 to be 64-bit, as
X86_X2APIC depends on X86_64.

In the course of this xen_running_on_version_or_later() needs to be
available more broadly. Move it from a PV-specific to a generic file,
considering that what it does isn't really PV-specific at all anyway.

Note that xen/interface/version.h cannot be included on its own; in
enlighten.c, which uses SCHEDOP_* anyway, include xen/interface/sched.h
first to resolve the apparently sole missing type (xen_ulong_t).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

Link: https://lore.kernel.org/r/983bb72f-53df-b6af-14bd-5e088bd06a08@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

swiotlb-xen: this is PV-only on x86

The code is unreachable for HVM or PVH, and it also makes little sense
in auto-translated environments. On Arm, with
xen_{create,destroy}_contiguous_region() both being stubs, I have a hard
time seeing what good the Xen specific variant does - the generic one
ought to be fine for all purposes there. Still Arm code explicitly
references symbols here, so the code will continue to be included there.

Instead of making PCI_XEN's "select" conditional, simply drop it -
SWIOTLB_XEN will be available unconditionally in the PV case anyway, and
is - as explained above - dead code in non-PV environments.

This in turn allows dropping the stubs for
xen_{create,destroy}_contiguous_region(), the former of which was broken
anyway - it failed to set the DMA handle output.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

Link: https://lore.kernel.org/r/5947b8ae-fdc7-225c-4838-84712265fc1e@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/pvcalls: backend can be a module

It's not clear to me why only the frontend has been tristate. Switch the
backend to be, too.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

Link: https://lore.kernel.org/r/54a6070c-92bb-36a3-2fc0-de9ccca438c5@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: Remove support for PV ACPI cpu/memory hotplug

Commit 76fc253723ad ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (which
is required for xen-acpi-{cpu|memory}-hotplug) and suggested that this
is temporary and will be soon fixed. This was in March 2013.

Further, commit cfafae940381 ("xen: rename dom0_op to platform_op")
renamed an interface used by memory hotplug code without updating that
code (as it was BROKEN and therefore not compiled). This was
in November 2015 and has gone unnoticed for over 5 year.

It is now clear that this code is of no interest to anyone and therefore
should be removed.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/1618336344-3162-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/x86: make XEN_BALLOON_MEMORY_HOTPLUG_LIMIT depend on MEMORY_HOTPLUG

The Xen memory hotplug limit should depend on the memory hotplug
generic option, rather than the Xen balloon configuration. It's
possible to have a kernel with generic memory hotplug enabled, but
without Xen balloon enabled, at which point memory hotplug won't work
correctly due to the size limitation of the p2m.

Rename the option to XEN_MEMORY_HOTPLUG_LIMIT since it's no longer
tied to ballooning.

Fixes: 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210324122424.58685-2-roger.pau@citrix.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: add helpers to allocate unpopulated memory

To be used in order to create foreign mappings. This is based on the
ZONE_DEVICE facility which is used by persistent memory devices in
order to create struct pages and kernel virtual mappings for the IOMEM
areas of such devices. Note that on kernels without support for
ZONE_DEVICE Xen will fallback to use ballooned pages in order to
create foreign mappings.

The newly added helpers use the same parameters as the existing
{alloc/free}_xenballooned_pages functions, which allows for in-place
replacement of the callers. Once a memory region has been added to be
used as scratch mapping space it will no longer be released, and pages
returned are kept in a linked list. This allows to have a buffer of
pages and prevents resorting to frequent additions and removals of
regions.

If enabled (because ZONE_DEVICE is supported) the usage of the new
functionality untangles Xen balloon and RAM hotplug from the usage of
unpopulated physical memory ranges to map foreign pages, which is the
correct thing to do in order to avoid mappings of foreign pages depend
on memory hotplug.

Note the driver is currently not enabled on Arm platforms because it
would interfere with the identity mapping required on some platforms.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20200901083326.21264-4-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>

x86/xen: remove 32-bit Xen PV guest support

Xen is requiring 64-bit machines today and since Xen 4.14 it can be
built without 32-bit PV guest support. There is no need to carry the
burden of 32-bit PV guest support in the kernel any longer, as new
guests can be either HVM or PVH, or they can use a 64 bit kernel.

Remove the 32-bit Xen PV support from the kernel.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

dma-mapping: make support for dma ops optional

Avoid the overhead of the dma ops support for tiny builds that only
use the direct mapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>

xen: enable BALLOON_MEMORY_HOTPLUG by default

Without it a PVH dom0 is mostly useless, as it would balloon down huge
amounts of RAM in order get physical address space to map foreign
memory and grants, ultimately leading to an out of memory situation.

Such option is also needed for HVM or PVH driver domains, since they
also require mapping grants into physical memory regions.

Suggested-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20200324150015.50496-2-roger.pau@citrix.com
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: expand BALLOON_MEMORY_HOTPLUG description

To mention it's also useful for PVH or HVM domains that require
mapping foreign memory or grants.

[boris: "non PV" instead of "translated" at Juergen's request]

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20200324150015.50496-1-roger.pau@citrix.com
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: Fix Kconfig indentation

Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
$ sed -e 's/^ /\t/' -i */Kconfig

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/mcelog: also allow building for 32-bit kernels

There's no apparent reason why it can be used on 64-bit only.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/gntdev: Use select for DMA_SHARED_BUFFER

DMA_SHARED_BUFFER can not be enabled by the user (it represents a library
set in the kernel). The kconfig convention is to use select for such
symbols so they are turned on implicitly when the user enables a kconfig
that needs them.

Otherwise the XEN_GNTDEV_DMABUF kconfig is overly difficult to enable.

Fixes: 932d6562179e ("xen/gntdev: Add initial support for dma-buf UAPI")
Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: remove tmem driver

The Xen tmem (transcendent memory) driver can be removed, as the
related Xen hypervisor feature never made it past the "experimental"
state and will be removed in future Xen versions (>= 4.13).

The xen-selfballoon driver depends on tmem, so it can be removed, too.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xen: Introduce shared buffer helpers for page directory...

based frontends. Currently the frontends which implement
similar code for sharing big buffers between frontend and
backend are para-virtualized DRM and sound drivers.
Both define the same way to share grant references of a
data buffer with the corresponding backend with little
differences.

Move shared code into a helper module, so there is a single
implementation of the same functionality for all.

This patch introduces code which is used by sound and display
frontend drivers without functional changes with the intention
to remove shared code from the corresponding drivers.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: remove redundant 'default n' from Kconfig

'default n' is the default value for any bool or tristate Kconfig
setting so there is no need to write it explicitly.

Also since commit f467c5640c29 ("kconfig: only write '# CONFIG_FOO
is not set' for visible symbols") the Kconfig behavior is the same
regardless of 'default n' being present or not:

...
One side effect of (and the main motivation for) this change is making
the following two definitions behave exactly the same:

config FOO
bool

config FOO
bool
default n

With this change, neither of these will generate a
'# CONFIG_FOO is not set' line (assuming FOO isn't selected/implied).
That might make it clearer to people that a bare 'default n' is
redundant.
...

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/balloon: Grammar s/Is it/It is/

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen: Make XEN_BACKEND selectable by DomU

XEN_BACKEND doesn't actually depend on XEN_DOM0. DomUs can serve
backends to other DomUs. One example is a service VM providing network
backends.

The original Kconfig defaulted Dom0 to y and it could be disabled. DomU
could not select the option. With the new Kconfig, we default y for
Dom0 and n for DomU. Either can then toggle the selection.

Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

xen/balloon: add runtime control for scrubbing ballooned out pages

Scrubbing pages on initial balloon down can take some time, especially
in nested virtualization case (nested EPT is slow). When HVM/PVH guest is
started with memory= significantly lower than maxmem=, all the extra
pages will be scrubbed before returning to Xen. But since most of them
weren't used at all at that point, Xen needs to populate them first
(from populate-on-demand pool). In nested virt case (Xen inside KVM)
this slows down the guest boot by 15-30s with just 1.5GB needed to be
returned to Xen.

Add runtime parameter to enable/disable it, to allow initially disabling
scrubbing, then enable it back during boot (for example in initramfs).
Such usage relies on assumption that a) most pages ballooned out during
initial boot weren't used at all, and b) even if they were, very few
secrets are in the guest at that time (before any serious userspace
kicks in).
Convert CONFIG_XEN_SCRUB_PAGES to CONFIG_XEN_SCRUB_PAGES_DEFAULT (also
enabled by default), controlling default value for the new runtime
switch.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen/gntdev: Add initial support for dma-buf UAPI

Add UAPI and IOCTLs for dma-buf grant device driver extension:
the extension allows userspace processes and kernel modules to
use Xen backed dma-buf implementation. With this extension grant
references to the pages of an imported dma-buf can be exported
for other domain use and grant references coming from a foreign
domain can be converted into a local dma-buf for local export.
Implement basic initialization and stubs for Xen DMA buffers'
support.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen/grant-table: Allow allocating buffers suitable for DMA

Extend grant table module API to allow allocating buffers that can
be used for DMA operations and mapping foreign grant references
on top of those.
The resulting buffer is similar to the one allocated by the balloon
driver in that proper memory reservation is made by
({increase|decrease}_reservation and VA mappings are updated if
needed).
This is useful for sharing foreign buffers with HW drivers which
cannot work with scattered buffers provided by the balloon driver,
but require DMAable memory instead.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: XEN_ACPI_PROCESSOR is Dom0-only

Add a respective dependency.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: introduce a Kconfig option to enable the pvcalls frontend

Also add pvcalls-front to the Makefile.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

xen: introduce a Kconfig option to enable the pvcalls backend

Also add pvcalls-back to the Makefile.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services

When running on Xen hypervisor, runtime services are supported through
hypercall. Add a Xen specific function to initialize runtime services.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Julien Grall <julien.grall@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>

xen_balloon: support memory auto onlining policy

Add support for the newly added kernel memory auto onlining policy to
Xen ballon driver.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Suggested-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

xen/PMU: Sysfs interface for setting Xen PMU mode

Set Xen's PMU mode via /sys/hypervisor/pmu/pmu_mode. Add XENPMU hypercall.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen: xensyms support

Export Xen symbols to dom0 via /proc/xen/xensyms (similar to
/proc/kallsyms).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

XEN / ACPI: Make XEN ACPI depend on X86

When ACPI is enabled on ARM64, XEN ACPI will also compiled
into the kernel, but XEN ACPI is x86 dependent, so introduce
CONFIG_XEN_ACPI to make it depend on x86 before XEN ACPI is
functional on ARM64.

CC: Julien Grall <julien.grall@linaro.org>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

x86/xen: prepare p2m list for memory hotplug

Commit 054954eb051f35e74b75a566a96fe756015352c8 ("xen: switch to linear
virtual mapped sparse p2m list") introduced a regression regarding to
memory hotplug for a pv-domain: as the virtual space for the p2m list
is allocated for the to be expected memory size of the domain only,
hotplugged memory above that size will not be usable by the domain.

Correct this by using a configurable size for the p2m list in case of
memory hotplug enabled (default supported memory size is 512 GB for
64 bit domains and 4 GB for 32 bit domains).

Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: <stable@vger.kernel.org> # 3.19+
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen: unify foreign GFN map/unmap for auto-xlated physmap guests

Auto-translated physmap guests (arm, arm64 and x86 PVHVM/PVH) map and
unmap foreign GFNs using the same method (updating the physmap).
Unify the two arm and x86 implementations into one commont one.

Note that on arm and arm64, the correct error code will be returned
(instead of always -EFAULT) and map/unmap failure warnings are no
longer printed. These changes are required if the foreign domain is
paging (-ENOENT failures are expected and must be propagated up to the
caller).

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

xen-scsiback: Add Xen PV SCSI backend driver

Introduces the Xen pvSCSI backend. With pvSCSI it is possible for a
Xen domU to issue SCSI commands to a SCSI LUN assigned to that
domU. The SCSI commands are passed to the pvSCSI backend in a driver
domain (usually Dom0) which is owner of the physical device. This
allows e.g. to use SCSI tape drives in a Xen domU.

The code is taken from the pvSCSI implementation in Xen done by
Fujitsu based on Linux kernel 2.6.18.

Changes from the original version are:
- port to upstream kernel
- put all code in just one source file
- adapt to Linux style guide
- use target core infrastructure instead doing pure pass-through
- enable module unloading
- support SG-list in grant page(s)
- support task abort
- remove redundant struct backend
- allocate resources dynamically
- correct minor error in scsiback_fast_flush_area
- free allocated resources in case of error during I/O preparation
- remove CDB emulation, now handled by target core infrastructure

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

xen: Put EFI machinery in place

This patch enables EFI usage under Xen dom0. Standard EFI Linux
Kernel infrastructure cannot be used because it requires direct
access to EFI data and code. However, in dom0 case it is not possible
because above mentioned EFI stuff is fully owned and controlled
by Xen hypervisor. In this case all calls from dom0 to EFI must
be requested via special hypercall which in turn executes relevant
EFI code in behalf of dom0.

When dom0 kernel boots it checks for EFI availability on a machine.
If it is detected then artificial EFI system table is filled.
Native EFI callas are replaced by functions which mimics them
by calling relevant hypercall. Later pointer to EFI system table
is passed to standard EFI machinery and it continues EFI subsystem
initialization taking into account that there is no direct access
to EFI boot services, runtime, tables, structures, etc. After that
system runs as usual.

This patch is based on Jan Beulich and Tang Liang work.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Tang Liang <liang.tang@oracle.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

xen: balloon: enable for ARM

Since c275a57f5ec3 "xen/balloon: Set balloon's initial state to number of
existing RAM pages" the balloon driver appears to work fine on ARM as far as I
can tell. Prior to that commit it was broken because on ARM RAM doesn't
typically start at zero, effectively leaving a big MMIO hole at the start.
This would cause the balloon driver to give away all of RAM at start of day,
which is rather inconvenient.

It was already enabled (or rather not excluded) on ARM64. The
c1d15f5c8bc1170dafe16e988e55437245966dfe
"xen/balloon: Seperate the auto-translate logic properly (v2)"
added in the proper plumbing to work with ARM and PVH type guests.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[v2: Added the bit about PVH]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

treewide: Fix typo in Kconfig

Correct spelling typo in Kconfig.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

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.

xen/tmem: do not allow XEN_TMEM on ARM64

tmem is not supported on arm or arm64 yet. Will revert this
once the Xen hypervisor supports it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/tmem: Remove the usage of '[no|]selfballoon' and use 'tmem.selfballooning' bool instead.

As the 'tmem' driver is the one that actually sets whether
it will use it (or not) so might as well make tmem responsible
for this knob.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.

As the 'tmem' driver is the one that actually sets whether
it will use it or not so might as well make tmem responsible
for this knob.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: SWIOTLB is only used on x86

Enabling SWIOTLB_XEN on ARM results in build errors because the
underlying SWIOTLB is only available on X86:

drivers/xen/swiotlb-xen.c: In function 'is_xen_swiotlb_buffer':
drivers/xen/swiotlb-xen.c:105:2: error: implicit declaration of function 'mfn_to_local_pfn

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: tmem: enable Xen tmem shim to be built/loaded as a module

Allow Xen tmem shim to be built/loaded as a module. Xen self-ballooning
and frontswap-selfshrinking are now also "lazily" initialized when the
Xen tmem shim is loaded as a module, unless explicitly disabled by
module parameters.

Note runtime dependency disallows loading if cleancache/frontswap lazy
initialization patches are not present.

If built-in (not built as a module), the original mechanism of enabling
via a kernel boot parameter is retained, but this should be considered
deprecated.

Note that module unload is explicitly not yet supported.

[v1: Removed the [CLEANCACHE|FRONTSWAP]_HAS_LAZY_INIT ifdef]
[v2: Squashed the xen/tmem: Remove the subsys call patch in]
[akpm@linux-foundation.org: fix build (disable_frontswap_selfshrinking undeclared)]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

xen/acpi-stub: Disable it b/c the acpi_processor_add is no longer called.

With the Xen ACPI stub code (CONFIG_XEN_STUB=y) enabled, the power
C and P states are no longer uploaded to the hypervisor.

The reason is that the Xen CPU hotplug code: xen-acpi-cpuhotplug.c
and the xen-acpi-stub.c register themselves as the "processor" type object.

That means the generic processor (processor_driver.c) stops
working and it does not call (acpi_processor_add) which populates the

per_cpu(processors, pr->id) = pr;

structure. The 'pr' is gathered from the acpi_processor_get_info function
which does the job of finding the C-states and figuring out PBLK address.

The 'processors->pr' is then later used by xen-acpi-processor.c (the one that
uploads C and P states to the hypervisor). Since it is NULL, we end
skip the gathering of _PSD, _PSS, _PCT, etc and never upload the power
management data.

The end result is that enabling the CONFIG_XEN_STUB in the build means that
xen-acpi-processor is not working anymore.

This temporary patch fixes it by marking the XEN_STUB driver as
BROKEN until this can be properly fixed.

CC: jinsong.liu@intel.com
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/acpi: ACPI cpu hotplug

This patch implement real Xen ACPI cpu hotplug driver as module.
When loaded, it replaces Xen stub driver.

For booting existed cpus, the driver enumerates them.
For hotadded cpus, which added at runtime and notify OS via
device or container event, the driver is invoked to add them,
parsing cpu information, hypercalling to Xen hypervisor to add
them, and finally setting up new /sys interface for them.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/acpi: ACPI memory hotplug

This patch implements real Xen acpi memory hotplug driver as module.
When loaded, it replaces Xen stub driver.

When an acpi memory device hotadd event occurs, it notifies OS and
invokes notification callback, adding related memory device and parsing
memory information, finally hypercall to xen hypervisor to add memory.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/stub: driver for memory hotplug

This patch create a file (xen-stub.c) for Xen stub drivers.
Xen stub drivers are used 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 and loaded on demand.

This patch is specific for Xen memory hotplug (other Xen logic
can add stub drivers on their own). The xen stub driver will
occupied earlier via subsys_initcall (than native memory hotplug
driver via module_init and so blocking native). Later real Xen
memory hotplug logic will unregister the stub driver and register
itself to take effect on demand.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: balloon: allow PVMMU interfaces to be compiled out

The ARM platform has no concept of PVMMU and therefor no
HYPERVISOR_update_va_mapping et al. Allow this code to be compiled out
when not required.

In some similar situations (e.g. P2M) we have defined dummy functions
to avoid this, however I think we can/should draw the line at dummying
out actual hypercalls.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

ARM: Xen: fix initial build problems

* The XEN_BALLOON code requires the balloon infrastructure that is not
getting built on ARM.

* The tmem hypercall is not available on ARM

* ARMv6 does not support cmpxchg on 16-bit words that are used in the
Xen grant table code, so we must ensure that Xen support is only
built on ARMv7-only kernels not combined ARMv6/v7 kernels.

* sys-hypervisor.c needs to include linux/err.h in order to use the
IS_ERR/PTR_ERR/ERR_PTR family of functions.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: xen-devel@lists.xensource.com

xen/mce: Add mcelog support for Xen platform

When MCA error occurs, it would be handled by Xen hypervisor first,
and then the error information would be sent to initial domain for logging.

This patch gets error information from Xen hypervisor and convert
Xen format error into Linux format mcelog. This logic is basically
self-contained, not touching other kernel components.

By using tools like mcelog tool users could read specific error information,
like what they did under native Linux.

To test follow directions outlined in Documentation/acpi/apei/einj.txt

Acked-and-tested-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Ke, Liping <liping.ke@intel.com>
Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/Kconfig: fix Kconfig layout

Fit it into 80 columns so that it is readable in menuconfig.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Fix typo in various Kconfig file

Correct spelling typo in various Kconfig file.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

xen/acpi: Fix Kconfig dependency on CPU_FREQ

The functions: "acpi_processor_*" sound like they depend on CONFIG_ACPI_PROCESSOR
but in reality they are exposed when CONFIG_CPU_FREQ=[y|m]. As such
update the Kconfig to have this dependency and fix compile issues:

ERROR: "acpi_processor_unregister_performance" [drivers/xen/xen-acpi-processor.ko] undefined!
ERROR: "acpi_processor_notify_smm" [drivers/xen/xen-acpi-processor.ko] undefined!
ERROR: "acpi_processor_register_performance" [drivers/xen/xen-acpi-processor.ko] undefined!
ERROR: "acpi_processor_preregister_performance" [drivers/xen/xen-acpi-processor.ko] undefined!

Note: We still need the CONFIG_ACPI
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/acpi-processor: Do not depend on CPU frequency scaling drivers.

With patch "xen/cpufreq: Disable the cpu frequency scaling drivers
from loading." we do not have to worry about said drivers loading
themselves before the xen-acpi-processor driver. Hence we can remove
the default selection (=y if CPU frequency drivers were built-in, or
=m if CPU frequency drivers were built as modules), and just
select =m for the default case.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/acpi-processor: C and P-state driver that uploads said data to hypervisor.

This driver solves three problems:
1). Parse and upload ACPI0007 (or PROCESSOR_TYPE) information to the
hypervisor - aka P-states (cpufreq data).
2). Upload the the Cx state information (cpuidle data).
3). Inhibit CPU frequency scaling drivers from loading.

The reason for wanting to solve 1) and 2) is such that the Xen hypervisor
is the only one that knows the CPU usage of different guests and can
make the proper decision of when to put CPUs and packages in proper states.
Unfortunately the hypervisor has no support to parse ACPI DSDT tables, hence it
needs help from the initial domain to provide this information. The reason
for 3) is that we do not want the initial domain to change P-states while the
hypervisor is doing it as well - it causes rather some funny cases of P-states
transitions.

For this to work, the driver parses the Power Management data and uploads said
information to the Xen hypervisor. It also calls acpi_processor_notify_smm()
to inhibit the other CPU frequency scaling drivers from being loaded.

Everything revolves around the 'struct acpi_processor' structure which
gets updated during the bootup cycle in different stages. At the startup, when
the ACPI parser starts, the C-state information is processed (processor_idle)
and saved in said structure as 'power' element. Later on, the CPU frequency
scaling driver (powernow-k8 or acpi_cpufreq), would call the the
acpi_processor_* (processor_perflib functions) to parse P-states information
and populate in the said structure the 'performance' element.

Since we do not want the CPU frequency scaling drivers from loading
we have to call the acpi_processor_* functions to parse the P-states and
call "acpi_processor_notify_smm" to stop them from loading.

There is also one oddity in this driver which is that under Xen, the
physical online CPU count can be different from the virtual online CPU count.
Meaning that the macros 'for_[online|possible]_cpu' would process only
up to virtual online CPU count. We on the other hand want to process
the full amount of physical CPUs. For that, the driver checks if the ACPI IDs
count is different from the APIC ID count - which can happen if the user
choose to use dom0_max_vcpu argument. In such a case a backup of the PM
structure is used and uploaded to the hypervisor.

[v1-v2: Initial RFC implementations that were posted]
[v3: Changed the name to passthru suggested by Pasi Kärkkäinen <pasik@iki.fi>]
[v4: Added vCPU != pCPU support - aka dom0_max_vcpus support]
[v5: Cleaned up the driver, fix bug under Athlon XP]
[v6: Changed the driver to a CPU frequency governor]
[v7: Jan Beulich <jbeulich@suse.com> suggestion to make it a cpufreq scaling driver
made me rework it as driver that inhibits cpufreq scaling driver]
[v8: Per Jan's review comments, fixed up the driver]
[v9: Allow to continue even if acpi_processor_preregister_perf.. fails]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: Add privcmd device driver

Access to arbitrary hypercalls is currently provided via xenfs. This
adds a standard character device to handle this. The support in xenfs
remains for backward compatibility and uses the device driver code.

Signed-off-by: Bastian Blank <waldi@debian.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: remove XEN_PLATFORM_PCI config option

Xen PVHVM needs xen-platform-pci, on the other hand xen-platform-pci is
useless in any other cases.
Therefore remove the XEN_PLATFORM_PCI config option and compile
xen-platform-pci built-in if XEN_PVHVM is selected.

Changes to v1:

- remove xen-platform-pci.o and just use platform-pci.o since it is not
externally visible anymore.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/self-balloon: Add dependency on tmem.

Without enabling CONFIG_XEN_TMEM we get this:

drivers/xen/xen-selfballoon.c:461: undefined reference to `tmem_enabled'

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/balloon: memory hotplug support for Xen balloon driver

Memory hotplug support for Xen balloon driver. It should be mentioned
that hotplugged memory is not onlined automatically. It should be onlined
by user through standard sysfs interface.

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.

Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

xen/pciback: Have 'passthrough' option instead of XEN_PCIDEV_BACKEND_PASS and XEN_PCIDEV_BACKEND_VPCI

.. compile options. This way the user can decide during runtime whether they
want the default 'vpci' (virtual pci passthrough) or where the PCI devices
are passed in without any BDF renumbering. The option 'passthrough' allows
the user to toggle the it from 0 (vpci) to 1 (passthrough).

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/pciback: Remove the DEBUG option.

The latter is easily fixed - by the developer compiling the
module with -DDEBUG. And during runtime - the loglvl provides
quite a lot of useful data.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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>

xen: tmem: self-ballooning and frontswap-selfshrinking

This patch introduces two in-kernel drivers for Xen transcendent memory
("tmem") functionality that complement cleancache and frontswap. Both
use control theory to dynamically adjust and optimize memory utilization.
Selfballooning controls the in-kernel Xen balloon driver, targeting a goal
value (vm_committed_as), thus pushing less frequently used clean
page cache pages (through the cleancache code) into Xen tmem where
Xen can balance needs across all VMs residing on the physical machine.
Frontswap-selfshrinking controls the number of pages in frontswap,
driving it towards zero (effectively doing a partial swapoff) when
in-kernel memory pressure subsides, freeing up RAM for other VMs.

More detail is provided in the header comment of xen-selfballooning.c.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>

[v8: konrad.wilk@oracle.com: set default enablement depending on frontswap]
[v7: konrad.wilk@oracle.com: fix capitalization and punctuation in comments]
[v6: fix frontswap-selfshrinking initialization]
[v6: konrad.wilk@oracle.com: fix init pr_infos; add comments about swap]
[v5: konrad.wilk@oracle.com: add NULL to attr list; move inits up to decls]
[v4: dkiper@net-space.pl: use strict_strtoul plus a few syntactic nits]
[v3: konrad.wilk@oracle.com: fix potential divides-by-zero]
[v3: konrad.wilk@oracle.com: add many more comments, fix nits]
[v2: rebased to linux-3.0-rc1]
[v2: Ian.Campbell@citrix.com: reorganize as new file (xen-selfballoon.c)]
[v2: dkiper@net-space.pl: proper access to vm_committed_as]
[v2: dkiper@net-space.pl: accounting fixes]
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: <xen-devel@lists.xensource.com>

xen: prepare tmem shim to handle frontswap

Provide the shim code for frontswap for Xen tmem even if the
frontswap patchset is not present yet. (The egg is before
the chicken.)

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Konrad Wilk <konrad.wilk@oracle.com>

xen/blkback: Move it from drivers/xen to drivers/block

.. and modify the Makefile and Kconfig files appropriately.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: add blkback support

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Conflicts:

drivers/xen/Makefile

xen: change xen/[gntdev/gntalloc] to default m

When CONFIG_XEN is enabled the gntdev and gntalloc driver will be
compiled as a module by default.

[v2: Added the fix for the gntalloc driver as well]

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen-gntalloc: Userspace grant allocation driver

This allows a userspace application to allocate a shared page for
implementing inter-domain communication or device drivers. These
shared pages can be mapped using the gntdev device or by the kernel
in another domain.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen-platform: Fix compile errors if CONFIG_PCI is not enabled.

drivers/xen/platform-pci.c:127: error: implicit declaration of function
'pci_request_region'
drivers/xen/platform-pci.c:165: error: implicit declaration of function
'pci_release_region'

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/gntdev: allow usermode to map granted pages

The gntdev driver allows usermode to map granted pages from other
domains. This is typically used to implement a Xen backend driver
in user mode.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/xenbus: making backend support modular is too complex

Impact: build fix

Making the xenbus backend support a separate module is needlessly complex
and causes build failures.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/xenbus: fixup checkpatch issues in xenbus_probe*

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: add backend driver support

Impact: backend device support

Add the basic machinery to support backend drivers.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[corresponds to 79727b851bac in git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen: separate out frontend xenbus

Impact: refactor

Make a distinct frontend xenbus, in preparation for adding a backend xenbus.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[corresponds to 2fd433a4188f in git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
with adjustments to reflect changes in the code which is moved]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

swiotlb-xen: On x86-32 builts, select SWIOTLB instead of depending on it.

We used to depend on CONFIG_SWIOTLB, but that is disabled by default.
So when compiling we get this compile error:

arch/x86/xen/pci-swiotlb-xen.c: In function 'pci_xen_swiotlb_detect':
arch/x86/xen/pci-swiotlb-xen.c:48: error: lvalue required as left operand of assignment

Fix it by actually activating the SWIOTLB library.

Reported-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/pci: Request ACS when Xen-SWIOTLB is activated.

It used to done in the Xen startup code but that is not really
appropiate.

[v2: Update Kconfig with PCI requirement]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Introduce CONFIG_XEN_PVHVM compile option

This patch introduce a CONFIG_XEN_PVHVM compile time option to
enable/disable Xen PV on HVM support.

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

swiotlb-xen: SWIOTLB library for Xen PV guest with PCI passthrough.

This patchset:

PV guests under Xen are running in an non-contiguous memory architecture.

When PCI pass-through is utilized, this necessitates an IOMMU for
translating bus (DMA) to virtual and vice-versa and also providing a
mechanism to have contiguous pages for device drivers operations (say DMA
operations).

Specifically, under Xen the Linux idea of pages is an illusion. It
assumes that pages start at zero and go up to the available memory. To
help with that, the Linux Xen MMU provides a lookup mechanism to
translate the page frame numbers (PFN) to machine frame numbers (MFN)
and vice-versa. The MFN are the "real" frame numbers. Furthermore
memory is not contiguous. Xen hypervisor stitches memory for guests
from different pools, which means there is no guarantee that PFN==MFN
and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
allocated in descending order (high to low), meaning the guest might
never get any MFN's under the 4GB mark.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Albert Herranz <albert_herranz@yahoo.es>
Cc: Ian Campbell <Ian.Campbell@citrix.com>

xen: Xen PCI platform device driver.

Add the xen pci platform device driver that is responsible
for initializing the grant table and xenbus in PV on HVM mode.
Few changes to xenbus and grant table are necessary to allow the delayed
initialization in HVM mode.
Grant table needs few additional modifications to work in HVM mode.

The Xen PCI platform device raises an irq every time an event has been
delivered to us. However these interrupts are only delivered to vcpu 0.
The Xen PCI platform interrupt handler calls xen_hvm_evtchn_do_upcall
that is a little wrapper around __xen_evtchn_do_upcall, the traditional
Xen upcall handler, the very same used with traditional PV guests.

When running on HVM the event channel upcall is never called while in
progress because it is a normal Linux irq handler (and we cannot switch
the irq chip wholesale to the Xen PV ones as we are running QEMU and
might have passed in PCI devices), therefore we cannot be sure that
evtchn_upcall_pending is 0 when returning.
For this reason if evtchn_upcall_pending is set by Xen we need to loop
again on the event channels set pending otherwise we might loose some
event channel deliveries.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

xen: add kconfig menu

Currently the xen support drivers are displayed in the main Device Drivers
menu of the config tools instead of in their own sub-menu, so move them to
their own sub-menu, like the rest of the driver world uses.

This keeps the main Device Drivers menu from becoming messy.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

xen: add /sys/hypervisor support

Adds support for Xen info under /sys/hypervisor. Taken from Novell 2.6.27
backport tree.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

xen: add /dev/xen/evtchn driver

This driver is used by application which wish to receive notifications
from the hypervisor or other guests via Xen's event channel
mechanism. In particular it is used by the xenstore daemon in domain
0.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

trivial: fix typos/grammar errors in Kconfig texts

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

xen: add xenfs to allow usermode <-> Xen interaction

The xenfs filesystem exports various interfaces to usermode. Initially
this exports a file to allow usermode to interact with xenbus/xenstore.

Traditionally this appeared in /proc/xen. Rather than extending procfs,
this patch adds a backward-compat mountpoint on /proc/xen, and provides
a xenfs filesystem which can be mounted there.

Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

xen: add balloon driver

The balloon driver allows memory to be dynamically added or removed from the domain,
in order to allow host memory to be balanced between multiple domains.

This patch introduces the Xen balloon driver, though it currently only
allows a domain to be shrunk from its initial size (and re-grown back to
that size). A later patch will add the ability to grow a domain beyond
its initial size.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>