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Juergen Gross 5f7f77400a xen/events: block rogue events for some time
In order to avoid high dom0 load due to rogue guests sending events at
high frequency, block those events in case there was no action needed
in dom0 to handle the events.

This is done by adding a per-event counter, which set to zero in case
an EOI without the XEN_EOI_FLAG_SPURIOUS is received from a backend
driver, and incremented when this flag has been set. In case the
counter is 2 or higher delay the EOI by 1 << (cnt - 2) jiffies, but
not more than 1 second.

In order not to waste memory shorten the per-event refcnt to two bytes
(it should normally never exceed a value of 2). Add an overflow check
to evtchn_get() to make sure the 2 bytes really won't overflow.

This is part of XSA-332.

Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Wei Liu <wl@xen.org>
2020-10-20 10:22:19 +02:00
arch x86/xen: Fix typo in xen_pagetable_p2m_free() 2020-10-04 18:41:34 -05:00
block block-5.9-2020-10-02 2020-10-02 14:34:52 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation xen/events: defer eoi in case of excessive number of events 2020-10-20 10:22:16 +02:00
drivers xen/events: block rogue events for some time 2020-10-20 10:22:19 +02:00
fs io_uring-5.9-2020-10-02 2020-10-02 14:38:10 -07:00
include xen/events: add a new "late EOI" evtchn framework 2020-10-20 10:21:59 +02:00
init bootconfig: init: make xbc_namebuf static 2020-09-18 22:17:05 -04:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Two tracing fixes: 2020-10-01 09:41:02 -07:00
lib random32: Restore __latent_entropy attribute on net_rand_state 2020-10-02 09:31:54 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/page_alloc: handle a missing case for memalloc_nocma_{save/restore} APIs 2020-10-03 11:28:12 -07:00
net Fixes: 2020-09-25 10:46:11 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts scripts/spelling.txt: fix malformed entry 2020-10-03 11:28:12 -07:00
security device_cgroup RCU warning fix from Amol Grover <frextrite@gmail.com> 2020-09-15 16:26:57 -07:00
sound sound fixes for 5.9-rc7 2020-09-24 09:00:05 -07:00
tools Five small fixes. The nested migration bug will be fixed 2020-09-25 17:15:19 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +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: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap mailmap: add older email addresses for Kees Cook 2020-09-19 13:13:38 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
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 pci-v5.9-fixes-2 2020-10-02 14:48:25 -07:00
Makefile Linux 5.9-rc8 2020-10-04 16:04:34 -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.