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author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-03-12 09:31:39 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-03-12 09:31:39 -0700 |
commit | 0e33cf955f07e3991e45109cb3e29fbc9ca51d06 (patch) | |
tree | 334a882eb66f2a0402afee1e0cb7e31c4f40cd77 /Documentation/admin-guide/kernel-parameters.txt | |
parent | 855684c7d938c2442f07eabc154e7532b4c1fbf9 (diff) | |
parent | 2a0180129d726a4b953232175857d442651b55a0 (diff) | |
download | linux-0e33cf955f07e3991e45109cb3e29fbc9ca51d06.tar.gz linux-0e33cf955f07e3991e45109cb3e29fbc9ca51d06.tar.bz2 linux-0e33cf955f07e3991e45109cb3e29fbc9ca51d06.zip |
Merge tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 RFDS mitigation from Dave Hansen:
"RFDS is a CPU vulnerability that may allow a malicious userspace to
infer stale register values from kernel space. Kernel registers can
have all kinds of secrets in them so the mitigation is basically to
wait until the kernel is about to return to userspace and has user
values in the registers. At that point there is little chance of
kernel secrets ending up in the registers and the microarchitectural
state can be cleared.
This leverages some recent robustness fixes for the existing MDS
vulnerability. Both MDS and RFDS use the VERW instruction for
mitigation"
* tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests
x86/rfds: Mitigate Register File Data Sampling (RFDS)
Documentation/hw-vuln: Add documentation for RFDS
x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
-rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 77c3d1a7f116..825398d66c69 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1136,6 +1136,26 @@ The filter can be disabled or changed to another driver later using sysfs. + reg_file_data_sampling= + [X86] Controls mitigation for Register File Data + Sampling (RFDS) vulnerability. RFDS is a CPU + vulnerability which may allow userspace to infer + kernel data values previously stored in floating point + registers, vector registers, or integer registers. + RFDS only affects Intel Atom processors. + + on: Turns ON the mitigation. + off: Turns OFF the mitigation. + + This parameter overrides the compile time default set + by CONFIG_MITIGATION_RFDS. Mitigation cannot be + disabled when other VERW based mitigations (like MDS) + are enabled. In order to disable RFDS mitigation all + VERW based mitigations need to be disabled. + + For details see: + Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst + driver_async_probe= [KNL] List of driver names to be probed asynchronously. * matches with all driver names. If * is specified, the @@ -3394,6 +3414,7 @@ nospectre_bhb [ARM64] nospectre_v1 [X86,PPC] nospectre_v2 [X86,PPC,S390,ARM64] + reg_file_data_sampling=off [X86] retbleed=off [X86] spec_rstack_overflow=off [X86] spec_store_bypass_disable=off [X86,PPC] |