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Marc Zyngier eb3df96102 KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode
[ Upstream commit bead02204e ]

Ricardo recently pointed out that the PMU chained counter emulation
in KVM wasn't quite behaving like the one on actual hardware, in
the sense that a chained counter would expose an overflow on
both halves of a chained counter, while KVM would only expose the
overflow on the top half.

The difference is subtle, but significant. What does the architecture
say (DDI0087 H.a):

- Up to PMUv3p4, all counters but the cycle counter are 32bit

- A 32bit counter that overflows generates a CHAIN event on the
  adjacent counter after exposing its own overflow status

- The CHAIN event is accounted if the counter is correctly
  configured (CHAIN event selected and counter enabled)

This all means that our current implementation (which uses 64bit
perf events) prevents us from emulating this overflow on the lower half.

How to fix this? By implementing the above, to the letter.

This largely results in code deletion, removing the notions of
"counter pair", "chained counters", and "canonical counter".
The code is further restructured to make the CHAIN handling similar
to SWINC, as the two are now extremely similar in behaviour.

Reported-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Link: https://lore.kernel.org/r/20221113163832.3154370-3-maz@kernel.org
Stable-dep-of: f6da81f650 ("KVM: arm64: PMU: Don't save PMCR_EL0.{C,P} for the vCPU")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-13 16:55:17 +02:00
arch KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode 2023-04-13 16:55:17 +02:00
block block: do not reverse request order when flushing plug list 2023-03-22 13:33:46 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: rsa-pkcs1pad - Use akcipher_request_complete 2023-03-10 09:33:03 +01:00
Documentation dt-bindings: mtd: jedec,spi-nor: Document CPOL/CPHA support 2023-04-06 12:10:55 +02:00
drivers dm: fix improper splitting for abnormal bios 2023-04-13 16:55:17 +02:00
fs NFSv4: Fix hangs when recovering open state after a server reboot 2023-04-06 12:10:54 +02:00
include KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode 2023-04-13 16:55:17 +02:00
init gcc: disable -Warray-bounds for gcc-11 too 2023-01-14 10:33:43 +01:00
io_uring io_uring: fix poll/netmsg alloc caches 2023-04-06 12:10:52 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel tracing: Fix wrong return in kprobe_event_gen_test.c 2023-04-06 12:10:41 +02:00
lib zstd: Fix definition of assert() 2023-04-06 12:10:38 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/ksm: fix race with VMA iteration and mm_struct teardown 2023-03-30 12:49:29 +02:00
net hsr: ratelimit only when errors are printed 2023-04-06 12:10:58 +02:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-02-06 08:06:34 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-02-01 08:34:37 +01:00
scripts modpost: Fix processing of CRCs on 32-bit build machines 2023-04-06 12:10:53 +02:00
security keys: Do not cache key in task struct if key is requested from kernel thread 2023-03-30 12:49:07 +02:00
sound ALSA: hda/realtek: Add quirk for Lenovo ZhaoYang CF4620Z 2023-04-06 12:10:54 +02:00
tools libbpf: Fix btf_dump's packed struct determination 2023-04-06 12:10:58 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Register /dev/kvm as the _very_ last thing during initialization 2023-03-10 09:34:11 +01:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.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: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS audit: update the mailing list in MAINTAINERS 2023-02-25 11:25:42 +01:00
Makefile Linux 6.1.23 2023-04-06 12:10:58 +02:00
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.