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Hou Wenlong 29da8c823a KVM: SVM: Re-load current, not host, TSC_AUX on #VMEXIT from SEV-ES guest
Prior to running an SEV-ES guest, set TSC_AUX in the host save area to the
current value in hardware, as tracked by the user return infrastructure,
instead of always loading the host's desired value for the CPU.  If the
pCPU is also running a non-SEV-ES vCPU, loading the host's value on #VMEXIT
could clobber the other vCPU's value, e.g. if the SEV-ES vCPU preempted
the non-SEV-ES vCPU, in which case KVM expects the other vCPU's TSC_AUX
value to be resident in hardware.

Note, unlike TDX, which blindly _zeroes_ TSC_AUX on TD-Exit, SEV-ES CPUs
can load an arbitrary value.  Stuff the current value in the host save
area instead of refreshing the user return cache so that KVM doesn't need
to track whether or not the vCPU actually enterred the guest and thus
loaded TSC_AUX from the host save area.

Opportunistically tag tsc_aux_uret_slot as read-only after init to guard
against unexpected modifications, and to make it obvious that using the
variable in sev_es_prepare_switch_to_guest() is safe.

Fixes: 916e3e5f26 ("KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX")
Cc: stable@vger.kernel.org
Suggested-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
[sean: handle the SEV-ES case in sev_es_prepare_switch_to_guest()]
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250923153738.1875174-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
History 2025-09-23 08:55:21 -07:00
arch
block block: restore default wbt enablement 2025-08-13 05:33:48 -06:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Documentation - Remove a transitional asm/cpuid.h header which was added only as 2025-08-17 06:53:15 -07:00
drivers - Remove a transitional asm/cpuid.h header which was added only as 2025-08-17 06:53:15 -07:00
fs xfs: Fixes for 6.17-rc2 2025-08-15 12:50:12 -07:00
include - Make sure sanity checks down in the mutex lock path happen on the correct 2025-08-17 05:57:47 -07:00
init Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
io_uring io_uring/io-wq: add check free worker before create new worker 2025-08-13 06:31:10 -06:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel - Make sure sanity checks down in the mutex lock path happen on the correct 2025-08-17 05:57:47 -07:00
lib Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/mremap: avoid expensive folio lookup on mremap folio pte batch 2025-08-11 23:00:59 -07:00
net Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
rust rust: kbuild: clean output before running rustdoc 2025-08-12 21:10:50 +02:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/tas2781: Normalize the volume kcontrol name 2025-08-14 11:17:12 +02:00
tools Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt KVM: SEV: Reject non-positive effective lengths during LAUNCH_UPDATE 2025-09-23 08:55:20 -07:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.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 Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
Makefile Linux 6.17-rc2 2025-08-17 15:22:10 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.