From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> commit e2c3c94788b08891dcf3dbe608f9880523ecd71b upstream. 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@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxx> Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lkml.kernel.org/r/20190412215118.294906495@localhost.localdomain Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/bugs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1091,7 +1091,8 @@ static ssize_t mds_show_state(char *buf) if (boot_cpu_has(X86_BUG_MSBDS_ONLY)) { 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],
