Merge tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-block.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 77c3d1a7f116f36284c4d27c5462f3c13abf85d2..825398d66c6963664cf34f3e4e64853e47d79211 100644 (file)
--- 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]