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Abhishek Sahu 385ecfdfb5 vfio: Add the device features for the low power entry and exit
This patch adds the following new device features for the low
power entry and exit in the header file. The implementation for the
same will be added in the subsequent patches.

- VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY
- VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY_WITH_WAKEUP
- VFIO_DEVICE_FEATURE_LOW_POWER_EXIT

For vfio-pci based devices, with the standard PCI PM registers,
all power states cannot be achieved. The platform-based power management
needs to be involved to go into the lowest power state. For doing low
power entry and exit with platform-based power management,
these device features can be used.

The entry device feature has two variants. These two variants are mainly
to support the different behaviour for the low power entry.
If there is any access for the VFIO device on the host side, then the
device will be moved out of the low power state without the user's
guest driver involvement. Some devices (for example NVIDIA VGA or
3D controller) require the user's guest driver involvement for
each low-power entry. In the first variant, the host can return the
device to low power automatically. The device will continue to
attempt to reach low power until the low power exit feature is called.
In the second variant, if the device exits low power due to an access,
the host kernel will signal the user via the provided eventfd and will
not return the device to low power without a subsequent call to one of
the low power entry features. A call to the low power exit feature is
optional if the user provided eventfd is signaled.

These device features only support VFIO_DEVICE_FEATURE_SET and
VFIO_DEVICE_FEATURE_PROBE operations.

Signed-off-by: Abhishek Sahu <abhsahu@nvidia.com>
Link: https://lore.kernel.org/r/20220829114850.4341-2-abhsahu@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-09-01 15:29:11 -06:00
arch Misc fixes: 2022-08-28 10:10:23 -07:00
block block-6.0-2022-08-26 2022-08-26 11:05:54 -07:00
certs Kbuild updates for v5.20 2022-08-10 10:40:41 -07:00
crypto crypto: blake2b: effectively disable frame size warning 2022-08-10 17:59:11 -07:00
Documentation Misc fixes: 2022-08-28 10:10:23 -07:00
drivers vfio: Split VFIO_GROUP_GET_STATUS into a function 2022-09-01 15:29:11 -06:00
fs Seventeen hotfixes. Mostly memory management things. Ten patches are 2022-08-28 14:49:59 -07:00
include vfio: Add the device features for the low power entry and exit 2022-09-01 15:29:11 -06:00
init arm64 fixes for -rc3 2022-08-26 11:32:53 -07:00
io_uring io_uring/net: save address for sendzc async execution 2022-08-25 07:52:30 -06:00
ipc Updates to various subsystems which I help look after. lib, ocfs2, 2022-08-07 10:03:24 -07:00
kernel Seventeen hotfixes. Mostly memory management things. Ten patches are 2022-08-28 14:49:59 -07:00
lib bitmap fixes for v6.0-rc3 2022-08-28 14:36:27 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/mprotect: only reference swap pfn page if type match 2022-08-28 14:02:46 -07:00
net Including fixes from ipsec and netfilter (with one broken Fixes tag). 2022-08-25 14:03:58 -07:00
samples Tracing updates for 5.20 / 6.0 2022-08-05 09:41:12 -07:00
scripts asm goto: eradicate CC_HAS_ASM_GOTO 2022-08-21 10:06:28 -07:00
security hardening fixes for v6.0-rc2 2022-08-19 13:56:14 -07:00
sound sound fixes for 6.0-rc2 2022-08-19 09:46:11 -07:00
tools Misc fixes: 2022-08-28 10:10:23 -07:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Drop unnecessary initialization of "ops" in kvm_ioctl_create_device() 2022-08-19 04:05:43 -04:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
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COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS bitmap fixes for v6.0-rc3 2022-08-28 14:36:27 -07:00
Makefile Linux 6.0-rc3 2022-08-28 15:05:29 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.