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Marc Zyngier 88430130cc KVM: arm64: timers: Use CNTHCTL_EL2 when setting non-CNTKCTL_EL1 bits
commit fe769e6c1f upstream.

It recently appeared that, when running VHE, there is a notable
difference between using CNTKCTL_EL1 and CNTHCTL_EL2, despite what
the architecture documents:

- When accessed from EL2, bits [19:18] and [16:10] of CNTKCTL_EL1 have
  the same assignment as CNTHCTL_EL2
- When accessed from EL1, bits [19:18] and [16:10] are RES0

It is all OK, until you factor in NV, where the EL2 guest runs at EL1.
In this configuration, CNTKCTL_EL11 doesn't trap, nor ends up in
the VNCR page. This means that any write from the guest affecting
CNTHCTL_EL2 using CNTKCTL_EL1 ends up losing some state. Not good.

The fix it obvious: don't use CNTKCTL_EL1 if you want to change bits
that are not part of the EL1 definition of CNTKCTL_EL1, and use
CNTHCTL_EL2 instead. This doesn't change anything for a bare-metal OS,
and fixes it when running under NV. The NV hypervisor will itself
have to work harder to merge the two accessors.

Note that there is a pending update to the architecture to address
this issue by making the affected bits UNKNOWN when CNTKCTL_EL1 is
used from EL2 with VHE enabled.

Fixes: c605ee2450 ("KVM: arm64: timers: Allow physical offset without CNTPOFF_EL2")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org # v6.4
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20230627140557.544885-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:56:42 +02:00
arch KVM: arm64: timers: Use CNTHCTL_EL2 when setting non-CNTKCTL_EL1 bits 2023-07-27 08:56:42 +02:00
block blk-crypto: use dynamic lock class for blk_crypto_profile::lock 2023-07-23 13:53:39 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
Documentation media: uapi: Fix [GS]_ROUTING ACTIVE flag value 2023-07-23 13:54:08 +02:00
drivers drm/amd/display: Keep PHY active for DP displays on DCN31 2023-07-27 08:56:40 +02:00
fs btrfs: fix race between balance and cancel/pause 2023-07-27 08:56:35 +02:00
include fuse: add feature flag for expire-only 2023-07-27 08:56:34 +02:00
init kbuild: Fix CFI failures with GCOV 2023-07-19 16:36:23 +02:00
io_uring io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area() 2023-07-27 08:56:31 +02:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel prctl: move PR_GET_AUXV out of PR_MCE_KILL 2023-07-27 08:56:33 +02:00
lib maple_tree: set the node limit when creating a new root node 2023-07-27 08:56:32 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/mlock: fix vma iterator conversion of apply_vma_lock_flags() 2023-07-27 08:56:32 +02:00
net can: bcm: Fix UAF in bcm_proc_show() 2023-07-27 08:56:36 +02:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:54:09 +02:00
scripts kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS 2023-07-19 16:37:00 +02:00
security keys: Fix linking a duplicate key to a keyring's assoc_array 2023-07-27 08:56:32 +02:00
sound ASoC: codecs: wcd938x: fix soundwire initialisation race 2023-07-27 08:56:42 +02:00
tools selftests: tc: add ConnTrack procfs kconfig 2023-07-27 08:56:37 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.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 *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.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: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
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 Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.6 2023-07-24 18:56:41 +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.