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02791a5c36
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Like Xu 02791a5c36 KVM: x86/pmu: Use PERF_TYPE_RAW to merge reprogram_{gp,fixed}counter() 
The code sketch for reprogram_{gp, fixed}_counter() is similar, while the
fixed counter using the PERF_TYPE_HARDWAR type and the gp being
able to use either PERF_TYPE_HARDWAR or PERF_TYPE_RAW type
depending on the pmc->eventsel value.

After 'commit 761875634a ("KVM: x86/pmu: Setup pmc->eventsel
for fixed PMCs")', the pmc->eventsel of the fixed counter will also have
been setup with the same semantic value and will not be changed during
the guest runtime.

The original story of using the PERF_TYPE_HARDWARE type is to emulate
guest architecture PMU on a host without architecture PMU (the Pentium 4),
for which the guest vPMC needs to be reprogrammed using the kernel
generic perf_hw_id. But essentially, "the HARDWARE is just a convenience
wrapper over RAW IIRC", quoated from Peterz. So it could be pretty safe
to use the PERF_TYPE_RAW type only in practice to program both gp and
fixed counters naturally in the reprogram_counter().

To make the gp and fixed counters more semantically symmetrical,
the selection of EVENTSEL_{USER, OS, INT} bits is temporarily translated
via fixed_ctr_ctrl before the pmc_reprogram_counter() call.

Cc: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20220518132512.37864-9-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-08 04:48:58 -04:00
arch KVM: x86/pmu: Use PERF_TYPE_RAW to merge reprogram_{gp,fixed}counter() 2022-06-08 04:48:58 -04:00
block for-5.19/drivers-2022-06-02 2022-06-03 10:25:56 -07:00
certs Kbuild updates for v5.19 2022-05-26 12:09:50 -07:00
crypto This update includes the following changes: 2022-05-27 18:06:49 -07:00
Documentation KVM: x86: Allow userspace to set maximum VCPU id for VM 2022-06-08 04:47:31 -04:00
drivers fix for breakage in #work.fd this window 2022-06-05 17:14:03 -07:00
fs fix for breakage in #work.fd this window 2022-06-05 17:14:03 -07:00
include KVM: s390: pvdump and selftest improvements 2022-06-07 12:28:53 -04:00
init This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
ipc These changes update the ipc sysctls so that they are fundamentally 2022-06-03 15:54:57 -07:00
kernel Merge branch 'kvm-5.19-early-fixes' into HEAD 2022-06-07 12:06:02 -04:00
lib Bitmap patches for 5.19-rc1 2022-06-04 14:04:27 -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 Hot fixes for 5.19-rc1. 2022-06-05 17:05:38 -07:00
net bluetooth: don't use bitmaps for random flag accesses 2022-06-05 16:28:41 -07:00
samples drm for 5.19-rc1 2022-05-25 16:18:27 -07:00
scripts A set of objtool fixes: 2022-06-05 09:45:27 -07:00
security Cleanups (and one fix) around struct mount handling. 2022-06-04 19:00:05 -07:00
sound USB / Thunderbolt changes for 5.19-rc1 2022-06-03 11:17:49 -07:00
tools selftests: kvm: replace ternary operator with min() 2022-06-08 04:48:24 -04:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Move kvm_arch_vcpu_precreate() under kvm->lock 2022-06-08 04:47:28 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +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 kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap Hot fixes for 5.19-rc1. 2022-06-05 17:05:38 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
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 Hot fixes for 5.19-rc1. 2022-06-05 17:05:38 -07:00
Makefile Linux 5.19-rc1 2022-06-05 17:18:54 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.