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Frank van der Linden 2ac44ab608 x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor
For F17h AMD CPUs, the CPB capability ('Core Performance Boost') is forcibly set,
because some versions of that chip incorrectly report that they do not have it.

However, a hypervisor may filter out the CPB capability, for good
reasons. For example, KVM currently does not emulate setting the CPB
bit in MSR_K7_HWCR, and unchecked MSR access errors will be thrown
when trying to set it as a guest:

	unchecked MSR access error: WRMSR to 0xc0010015 (tried to write 0x0000000001000011) at rIP: 0xffffffff890638f4 (native_write_msr+0x4/0x20)

	Call Trace:
	boost_set_msr+0x50/0x80 [acpi_cpufreq]
	cpuhp_invoke_callback+0x86/0x560
	sort_range+0x20/0x20
	cpuhp_thread_fun+0xb0/0x110
	smpboot_thread_fn+0xef/0x160
	kthread+0x113/0x130
	kthread_create_worker_on_cpu+0x70/0x70
	ret_from_fork+0x35/0x40

To avoid this issue, don't forcibly set the CPB capability for a CPU
when running under a hypervisor.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: jiaxun.yang@flygoat.com
Fixes: 0237199186 ("x86/CPU/AMD: Set the CPB bit unconditionally on F17h")
Link: http://lkml.kernel.org/r/20190522221745.GA15789@dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com
[ Minor edits to the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
History 2019-05-24 08:50:32 +02:00
arch x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor 2019-05-24 08:50:32 +02:00
block for-5.2/block-post-20190516 2019-05-16 19:08:15 -07:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-22 08:28:16 -07:00
drivers First round of arm64 fixes for -rc2 2019-05-22 08:36:16 -07:00
fs Fix a gfs2 sign extension bug introduced in v4.3. 2019-05-22 08:31:09 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-22 08:28:16 -07:00
init treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
ipc ipc: do cyclic id allocation for the ipc object. 2019-05-14 19:52:52 -07:00
kernel SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
lib SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-22 08:28:16 -07:00
samples treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
scripts SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
security selinux/stable-5.2 PR 20190521 2019-05-21 12:51:20 -07:00
sound treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-22 08:28:16 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-20 08:21:07 -07:00
Makefile Linux 5.2-rc1 2019-05-19 15:47:09 -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.