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Tom Lendacky aed15fc08f x86/sev: Evict cache lines during SNP memory validation
Commit 7b306dfa32 upstream.

An SNP cache coherency vulnerability requires a cache line eviction
mitigation when validating memory after a page state change to private.
The specific mitigation is to touch the first and last byte of each 4K
page that is being validated. There is no need to perform the mitigation
when performing a page state change to shared and rescinding validation.

CPUID bit Fn8000001F_EBX[31] defines the COHERENCY_SFW_NO CPUID bit that,
when set, indicates that the software mitigation for this vulnerability is
not needed.

Implement the mitigation and invoke it when validating memory (making it
private) and the COHERENCY_SFW_NO bit is not set, indicating the SNP guest
is vulnerable.

Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-08-15 12:14:12 +02:00
arch x86/sev: Evict cache lines during SNP memory validation 2025-08-15 12:14:12 +02:00
block block: ensure discard_granularity is zero when discard is not supported 2025-08-15 12:14:05 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP() 2025-07-17 18:37:24 +02:00
Documentation netlink: specs: ethtool: fix module EEPROM input/output arguments 2025-08-15 12:14:05 +02:00
drivers net: usbnet: Fix the wrong netif_carrier_on() call 2025-08-15 12:14:12 +02:00
fs smb: server: Fix extension string in ksmbd_extract_shortname() 2025-08-15 12:14:11 +02:00
include net: usbnet: Avoid potential RCU stall on LINK_CHANGE event 2025-08-15 12:14:12 +02:00
init io_uring: fix breakage in EXPERT menu 2025-08-15 12:13:32 +02:00
io_uring io_uring/poll: fix POLLERR handling 2025-07-24 08:56:23 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel perf/core: Prevent VMA split of buffer mappings 2025-08-15 12:14:09 +02:00
lib lib/alloc_tag: do not acquire non-existent lock in alloc_tag_top_users() 2025-07-17 18:37:14 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: khugepaged: fix call hpage_collapse_scan_file() for anonymous vma 2025-08-01 09:48:47 +01:00
net vsock: Do not allow binding to VMADDR_PORT_ANY 2025-08-15 12:14:09 +02:00
rust rust: use #[used(compiler)] to fix build and modpost with Rust >= 1.89.0 2025-07-24 08:56:37 +02:00
samples samples: mei: Fix building on musl libc 2025-08-15 12:13:38 +02:00
scripts kconfig: qconf: fix ConfigList::updateListAllforAll() 2025-08-15 12:14:03 +02:00
security apparmor: Fix unaligned memory accesses in KUnit test 2025-08-15 12:13:59 +02:00
sound ALSA: hda/ca0132: Fix missing error handling in ca0132_alt_select_out() 2025-08-15 12:14:07 +02:00
tools selftests/bpf: Fix build error with llvm 19 2025-08-15 12:14:10 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Allow CPU to reschedule while setting per-page memory attributes 2025-07-17 18:37:08 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.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 Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.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: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
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 MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.41 2025-08-01 09:48:47 +01:00
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.