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Dave Jiang 56fc39f5a3 dmaengine: idxd: handle interrupt handle revoked event
"Interrupt handle revoked" is an event that happens when the driver is
running on a guest kernel and the VM is migrated to a new machine.
The device will trigger an interrupt that signals to the guest driver
that the interrupt handles need to be replaced.

The misc irq thread function calls a helper function to handle the
event. The function uses the WQ percpu_ref to quiesce the kernel
submissions. It then replaces the interrupt handles by requesting
interrupt handle command for each I/O MSIX vector. Once the handle is
updated, the driver will unblock the submission path to allow new
submissions.

The submitter will attempt to acquire a percpu_ref before submission. When
the request fails, it will wait on the wq_resurrect 'completion'.

The driver does anticipate the possibility of descriptors being submitted
before the WQ percpu_ref is killed. If a descriptor has already been
submitted, it will return with incorrect interrupt handle status. The
descriptor will be re-submitted with the new interrupt handle on the
completion path. For descriptors with incorrect interrupt handles,
completion interrupt won't be triggered.

At the completion of the interrupt handle refresh, the handling function
will call idxd_int_handle_refresh_drain() to issue drain descriptors to
each of the wq with associated interrupt handle. The drain descriptor will have
interrupt request set but without completion record. This will ensure all
descriptors with incorrect interrupt completion handle get drained and
a completion interrupt is triggered for the guest driver to process them.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Co-Developed-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163528420189.3925689.18212568593220415551.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2021-11-22 11:21:26 +05:30
arch parisc architecture build-, trace-, backtrace- and page table fixes 2021-11-14 11:53:59 -08:00
block blk-mq: fix filesystem I/O request allocation 2021-11-12 09:31:13 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
Documentation Devicetree fixes for v5.16, take 1: 2021-11-14 11:11:51 -08:00
drivers dmaengine: idxd: handle interrupt handle revoked event 2021-11-22 11:21:26 +05:30
fs Minor tweaks for 5.16: 2021-11-14 12:18:22 -08:00
include Devicetree fixes for v5.16, take 1: 2021-11-14 11:11:51 -08:00
init kconfig: Add support for -Wimplicit-fallthrough 2021-11-14 13:27:30 -08:00
ipc ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL 2021-11-09 10:02:53 -08:00
kernel A single fix for POSIX CPU timers to address a problem where POSIX CPU 2021-11-14 10:43:38 -08:00
lib Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm Revert "mm: shmem: don't truncate page if memory failure happens" 2021-11-13 12:03:03 -08:00
net One notable change here is that async creates and unlinks introduced 2021-11-13 11:31:07 -08:00
samples Add gitignore file for samples/fanotify/ subdirectory 2021-11-07 11:19:24 -08:00
scripts coccinelle patches for 5.16-rc1 2021-11-13 10:45:17 -08:00
security net,lsm,selinux: revert the security_sctp_assoc_established() hook 2021-11-12 12:07:02 -05:00
sound sound fixes for 5.16-rc1 2021-11-12 12:17:30 -08:00
tools A single fix for static calls to make the trampoline patching more robust 2021-11-14 10:30:17 -08:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt KVM: generalize "bugged" VM to "dead" VM 2021-11-11 10:35:26 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 - Add the model number of a new, Raptor Lake CPU, to intel-family.h 2021-11-14 09:29:03 -08:00
Makefile Linux 5.16-rc1 2021-11-14 13:56:52 -08:00
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.