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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt2
-rw-r--r--arch/x86/kernel/cpu/bugs.c5
2 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6fa7895885c9..9240b2caa0b1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2405,6 +2405,7 @@
spectre_v2_user=off [X86]
spec_store_bypass_disable=off [X86,PPC]
l1tf=off [X86]
+ mds=off [X86]
auto (default)
Mitigate all CPU vulnerabilities, but leave SMT
@@ -2419,6 +2420,7 @@
if needed. This is for users who always want to
be fully mitigated, even if it means losing SMT.
Equivalent to: l1tf=flush,nosmt [X86]
+ mds=full,nosmt [X86]
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 4891101cf990..2769e0f5c686 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -231,7 +231,7 @@ static const char * const mds_strings[] = {
static void __init mds_select_mitigation(void)
{
- if (!boot_cpu_has_bug(X86_BUG_MDS)) {
+ if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) {
mds_mitigation = MDS_MITIGATION_OFF;
return;
}
@@ -242,7 +242,8 @@ static void __init mds_select_mitigation(void)
static_branch_enable(&mds_user_clear);
- if (mds_nosmt && !boot_cpu_has(X86_BUG_MSBDS_ONLY))
+ if (!boot_cpu_has(X86_BUG_MSBDS_ONLY) &&
+ (mds_nosmt || cpu_mitigations_auto_nosmt()))
cpu_smt_disable(false);
}