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Marc Zyngier 2a5f1b67ec KVM: arm64: Don't access PMCR_EL0 when no PMU is available
We reset the guest's view of PMCR_EL0 unconditionally, based on
the host's view of this register. It is however legal for an
implementation not to provide any PMU, resulting in an UNDEF.

The obvious fix is to skip the reset of this shadow register
when no PMU is available, sidestepping the issue entirely.
If no PMU is available, the guest is not able to request
a virtual PMU anyway, so not doing nothing is the right thing
to do!

It is unlikely that this bug can hit any HW implementation
though, as they all provide a PMU. It has been found using nested
virt with the host KVM not implementing the PMU itself.

Fixes: ab9468340d ("arm64: KVM: Add access handler for PMCR register")
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201210083059.1277162-1-maz@kernel.org
2020-12-22 10:47:09 +00:00
arch KVM: arm64: Don't access PMCR_EL0 when no PMU is available 2020-12-22 10:47:09 +00:00
block block: add a return value to set_capacity_revalidate_and_notify 2020-11-12 13:59:04 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
Documentation Merge remote-tracking branch 'origin/kvm-arm64/psci-relay' into kvmarm-master/next 2020-12-09 10:00:24 +00:00
drivers Merge remote-tracking branch 'origin/kvm-arm64/psci-relay' into kvmarm-master/next 2020-12-09 10:00:24 +00:00
fs Merge branch 'akpm' (patches from Andrew) 2020-11-14 12:35:11 -08:00
include Merge remote-tracking branch 'origin/kvm-arm64/psci-relay' into kvmarm-master/next 2020-12-09 10:00:24 +00:00
init bootconfig: Extend the magic check range to the preceding 3 bytes 2020-11-12 20:36:52 -05:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel A set of fixes for perf: 2020-11-15 09:46:36 -08:00
lib drm fixes for 5.10-rc3 2020-11-06 12:54:00 -08:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm Merge branch 'for-5.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu 2020-11-15 08:57:19 -08:00
net Networking fixes for 5.10-rc4, including fixes from the bpf subtree. 2020-11-12 14:02:04 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-11-06 17:49:34 -08:00
scripts Networking fixes for 5.10-rc4, including fixes from the bpf subtree. 2020-11-12 14:02:04 -08:00
security selinux/stable-5.10 PR 20201113 2020-11-14 12:04:02 -08:00
sound ASoC: Fixes for v5.10 2020-11-05 18:19:32 +01:00
tools KVM: arm64: selftests: Filter out DEMUX registers 2020-11-27 19:46:47 +00:00
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: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.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: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: fix entry for Dmitry Baryshkov/Eremin-Solenikov 2020-11-14 11:26:03 -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 Sangbeom Kim to credits 2020-10-26 10:11:18 +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 USB/Thunderbolt fixes for 5.10-rc4 2020-11-15 10:02:41 -08:00
Makefile Linux 5.10-rc4 2020-11-15 16:44:31 -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.