peter/spectre-meltdown-checker
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spectre-meltdown-checker
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L1TF/Linux: detect SMT via sysfs 

We can figure out whether SMT is enabled or not, by checking the
topology of the CPUs, as it is exposed in /sys.

This means the information is available also when we are running
in `--sysfs-only` mode.
This commit is contained in:
Dario Faggioli 2019-04-19 14:30:10 +02:00
parent 26a5fe018a
commit e1a2cae2c0
1 changed files with 17 additions and 8 deletions
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25
spectre-meltdown-checker.sh
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@ -3932,16 +3932,25 @@ check_CVE_2018_3646_linux()
fi
smt_enabled=-1
if [ "$opt_sysfs_only" != 1 ]; then
_info_nol " * Hyper-Threading (SMT) is enabled: "
is_cpu_smt_enabled; smt_enabled=$?
if [ "$smt_enabled" = 0 ]; then
pstatus yellow YES
elif [ "$smt_enabled" = 1 ]; then
pstatus green NO
_info_nol " * Hyper-Threading (SMT) is enabled: "
if [ "$opt_sysfs_only" = 1 ]; then
# if SMT is on, `siblings_list` has more than one element,
# separated by ','. Also, it is safe enough to assume that
# cpu0 (1) always exists, and (2) is always online.
if ! grep -q ',' /sys/devices/system/cpu/cpu0/topology/thread_siblings_list ; then
smt_enabled=1 # means disabled!
else
pstatus yellow UNKNOWN
smt_enabled=0
fi
else
is_cpu_smt_enabled; smt_enabled=$?
fi
if [ "$smt_enabled" = 0 ]; then
pstatus yellow YES
elif [ "$smt_enabled" = 1 ]; then
pstatus green NO
else
pstatus yellow UNKNOWN
fi
if ! is_cpu_vulnerable "$cve"; then