UBUNTU: SAUCE: Synchronize MDS mitigations with upstream

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / kernel / cpu / bugs.c

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 0229f3fb43333b14c6edf3b99743ad274f5a53a8..9ad7faa33c587c7b3c3e879a500f035aad874412 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -229,7 +229,7 @@ static const char * const mds_strings[] = {
        [MDS_MITIGATION_VMWERV] = "Vulnerable: Clear CPU buffers attempted, no microcode",
 };
 
-static void mds_select_mitigation(void)
+static void __init mds_select_mitigation(void)
 {
        if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) {
                mds_mitigation = MDS_MITIGATION_OFF;
@@ -678,12 +678,14 @@ static void update_indir_branch_cond(void)
 static void update_mds_branch_idle(void)
 {
        /*
-        * Enable the idle clearing on CPUs which are affected only by
-        * MDBDS and not any other MDS variant. The other variants cannot
-        * be mitigated when SMT is enabled, so clearing the buffers on
-        * idle would be a window dressing exercise.
+        * Enable the idle clearing if SMT is active on CPUs which are
+        * affected only by MSBDS and not any other MDS variant.
+        *
+        * The other variants cannot be mitigated when SMT is enabled, so
+        * clearing the buffers on idle just to prevent the Store Buffer
+        * repartitioning leak would be a window dressing exercise.
         */
-       if (!boot_cpu_has(X86_BUG_MSBDS_ONLY))
+       if (!boot_cpu_has_bug(X86_BUG_MSBDS_ONLY))
                return;
 
        if (sched_smt_active())
@@ -715,7 +717,7 @@ void arch_smt_update(void)
                break;
        }
 
-       switch(mds_mitigation) {
+       switch (mds_mitigation) {
        case MDS_MITIGATION_FULL:
        case MDS_MITIGATION_VMWERV:
                if (sched_smt_active() && !boot_cpu_has(X86_BUG_MSBDS_ONLY))
@@ -1125,7 +1127,7 @@ static void __init l1tf_select_mitigation(void)
                pr_info("You may make it effective by booting the kernel with mem=%llu parameter.\n",
                                half_pa);
                pr_info("However, doing so will make a part of your RAM unusable.\n");
-               pr_info("Reading https://www.kernel.org/doc/html/latest/admin-guide/l1tf.html might help you decide.\n");
+               pr_info("Reading https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html might help you decide.\n");
                return;
        }