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x86/speculation/mds: Print SMT vulnerable on MSBDS with mitigations off

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This code is only for CPUs which are affected by MSBDS, but are *not*
affected by the other two MDS issues.

For such CPUs, enabling the mds_idle_clear mitigation is enough to
mitigate SMT.

However if user boots with 'mds=off' and still has SMT enabled, we should
not report that SMT is mitigated:

$cat /sys//devices/system/cpu/vulnerabilities/mds
Vulnerable; SMT mitigated

But rather:
Vulnerable; SMT vulnerable

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20190412215118.294906495@localhost.localdomain
This commit is contained in:
Konrad Rzeszutek Wilk 2019-04-12 17:50:58 -04:00 committed by Thomas Gleixner
parent cae5ec3426
commit e2c3c94788
1 changed files with 2 additions and 1 deletions
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3
arch/x86/kernel/cpu/bugs.c
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@ -1204,7 +1204,8 @@ static ssize_t mds_show_state(char *buf)
if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) { if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) {
return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation], return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],
sched_smt_active() ? "mitigated" : "disabled"); (mds_mitigation == MDS_MITIGATION_OFF ? "vulnerable" :
sched_smt_active() ? "mitigated" : "disabled"));
} }
return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation], return sprintf(buf, "%s; SMT %s\n", mds_strings[mds_mitigation],