linux.git/include/uapi/xen, branch v6.6.131

xen: irqfd: Use _IOW instead of the internal _IOC() macro

2023-11-20T10:59:12+00:00

[ Upstream commit 767e33ca47dd8ace7769e0b0c19d7b0c38b2f72d ]

_IOC() an internal helper that we should not use in driver code.  In
particular, we got the data direction wrong here, which breaks a number
of tools, as having "_IOC_NONE" should never be paired with a nonzero
size.

Use _IOW() instead.

Fixes: f8941e6c4c71 ("xen: privcmd: Add support for irqfd")
Reported-by: Arnd Bergmann 
Closes: https://lore.kernel.org/all/268a2031-63b8-4c7d-b1e5-8ab83ca80b4a@app.fastmail.com/
Signed-off-by: Viresh Kumar 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/599ca6f1b9dd2f0e6247ea37bee3ea6827404b6d.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen: Make struct privcmd_irqfd's layout architecture independent

2023-11-20T10:59:12+00:00

[ Upstream commit 8dd765a5d769c521d73931850d1c8708fbc490cb ]

Using indirect pointers in an ioctl command argument means that the
layout is architecture specific, in particular we can't use the same one
from 32-bit compat tasks. The general recommendation is to have __u64
members and use u64_to_user_ptr() to access it from the kernel if we are
unable to avoid the pointers altogether.

Fixes: f8941e6c4c71 ("xen: privcmd: Add support for irqfd")
Reported-by: Arnd Bergmann 
Closes: https://lore.kernel.org/all/268a2031-63b8-4c7d-b1e5-8ab83ca80b4a@app.fastmail.com/
Signed-off-by: Viresh Kumar 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/a4ef0d4a68fc858b34a81fd3f9877d9b6898eb77.1697439990.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross 
Signed-off-by: Sasha Levin

xen: privcmd: Add support for irqfd

2023-08-22T10:12:50+00:00

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 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/8e724ac1f50c2bc1eb8da9b3ff6166f1372570aa.1692697321.git.viresh.kumar@linaro.org
Signed-off-by: Juergen Gross

xen/evtchn: Introduce new IOCTL to bind static evtchn

2023-07-26T06:42:34+00:00

Xen 4.17 supports the creation of static evtchns. To allow user space
application to bind static evtchns introduce new ioctl
"IOCTL_EVTCHN_BIND_STATIC". Existing IOCTL doing more than binding
that’s why we need to introduce the new IOCTL to only bind the static
event channels.

Static evtchns to be available for use during the lifetime of the
guest. When the application exits, __unbind_from_irq() ends up being
called from release() file operations because of that static evtchns
are getting closed. To avoid closing the static event channel, add the
new bool variable "is_static" in "struct irq_info" to mark the event
channel static when creating the event channel to avoid closing the
static evtchn.

Also, take this opportunity to remove the open-coded version of the
evtchn close in drivers/xen/evtchn.c file and use xen_evtchn_close().

Signed-off-by: Rahul Singh 
Reviewed-by: Oleksandr Tyshchenko 
Acked-by: Stefano Stabellini 
Link: https://lore.kernel.org/r/ae7329bf1713f83e4aad4f3fa0f316258c40a3e9.1689677042.git.rahul.singh@arm.com
Signed-off-by: Juergen Gross

Improve docs for IOCTL_GNTDEV_MAP_GRANT_REF

2022-02-03T07:23:32+00:00

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Content-Type: multipart/mixed; boundary="------------g0T69ASidFiPhh4eOY4XzIg1"

--------------g0T69ASidFiPhh4eOY4XzIg1
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

The current implementation of gntdev guarantees that the first call to
IOCTL_GNTDEV_MAP_GRANT_REF will set @index to 0.  This is required to
use gntdev for Wayland, which is a future desire of Qubes OS.
Additionally, requesting zero grants results in an error, but this was
not documented either.  Document both of these.

Signed-off-by: Demi Marie Obenour 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/f66c5a4e-2034-00b5-a635-6983bd999c07@gmail.com
Signed-off-by: Juergen Gross

xen/gntdev: gntdev.h: drop a duplicated word

2020-08-03T05:46:42+00:00

Drop the repeated word "of" in a comment.

Signed-off-by: Randy Dunlap 
Reviewed-by: Juergen Gross 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: xen-devel@lists.xenproject.org
Link: https://lore.kernel.org/r/20200719003317.21454-1-rdunlap@infradead.org
Signed-off-by: Juergen Gross

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

2018-07-27T03:05:14+00:00

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 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen/gntdev: Allow mappings for DMA buffers

2018-07-27T03:05:14+00:00

Allow mappings for DMA backed  buffers if grant table module
supports such: this extends grant device to not only map buffers
made of balloon pages, but also from buffers allocated with
dma_alloc_xxx.

Signed-off-by: Oleksandr Andrushchenko 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE

2018-05-14T13:25:37+00:00

My recent Xen patch series introduces a new HYPERVISOR_memory_op to
support direct priv-mapping of certain guest resources (such as ioreq
pages, used by emulators) by a tools domain, rather than having to access
such resources via the guest P2M.

This patch adds the necessary infrastructure to the privcmd driver and
Xen MMU code to support direct resource mapping.

NOTE: The adjustment in the MMU code is partially cosmetic. Xen will now
      allow a PV tools domain to map guest pages either by GFN or MFN, thus
      the term 'mfn' has been swapped for 'pfn' in the lower layers of the
      remap code.

Signed-off-by: Paul Durrant 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Juergen Gross

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11+00:00

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be.  This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier.  The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

   NOTE! This copyright does *not* cover user programs that use kernel
   services by normal system calls - this is merely considered normal use
   of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier.  The format
is:
        ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text.  The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.  See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman