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authorJosh Poimboeuf <jpoimboe@redhat.com>2019-04-02 09:59:33 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-14 19:19:41 +0200
commitf02eee68e2fc2ded5d620684599826d10392d055 (patch)
tree0b42ce29a4bf2f6f30b67a30e39b6e8222fe18b4 /Documentation
parent3880bc168f2188b7e039a9b16a13dbff7b80d462 (diff)
x86/speculation/mds: Add mds=full,nosmt cmdline option
commit d71eb0ce109a124b0fa714832823b9452f2762cf upstream. Add the mds=full,nosmt cmdline option. This is like mds=full, but with SMT disabled if the CPU is vulnerable. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Acked-by: Jiri Kosina <jkosina@suse.cz> [bwh: Backported to 4.9: adjust filenames] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/hw-vuln/mds.rst3
-rw-r--r--Documentation/kernel-parameters.txt6
2 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/hw-vuln/mds.rst b/Documentation/hw-vuln/mds.rst
index ff6bfdb97eee..aec9e49256b5 100644
--- a/Documentation/hw-vuln/mds.rst
+++ b/Documentation/hw-vuln/mds.rst
@@ -260,6 +260,9 @@ time with the option "mds=". The valid arguments for this option are:
It does not automatically disable SMT.
+ full,nosmt The same as mds=full, with SMT disabled on vulnerable
+ CPUs. This is the complete mitigation.
+
off Disables MDS mitigations completely.
============ =============================================================
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7164790b82c0..4c134700c120 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2341,8 +2341,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
This parameter controls the MDS mitigation. The
options are:
- full - Enable MDS mitigation on vulnerable CPUs
- off - Unconditionally disable MDS mitigation
+ full - Enable MDS mitigation on vulnerable CPUs
+ full,nosmt - Enable MDS mitigation and disable
+ SMT on vulnerable CPUs
+ off - Unconditionally disable MDS mitigation
Not specifying this option is equivalent to
mds=full.