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| author | Stéphane Lesimple <speed47_github@speed47.net> | 2018-01-14 17:18:34 +0100 |
|---|---|---|
| committer | Stéphane Lesimple <speed47_github@speed47.net> | 2018-01-14 17:18:34 +0100 |
| commit | d96093171a6e6e3decab08b868abd533223eed37 (patch) | |
| tree | 1f3dbd98c39c5b3c0a9d7825a9a1d97d9cc7c000 | |
| parent | dcc4488340790645cf21d28aca06331a1b7b0e79 (diff) | |
| download | spectre-meltdown-checker-d96093171a6e6e3decab08b868abd533223eed37.tar.lz spectre-meltdown-checker-d96093171a6e6e3decab08b868abd533223eed37.tar.xz spectre-meltdown-checker-d96093171a6e6e3decab08b868abd533223eed37.zip | |
verbose: add PCID check for performance impact of PTI
| -rwxr-xr-x | spectre-meltdown-checker.sh | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh index 464c352..45e70f5 100755 --- a/spectre-meltdown-checker.sh +++ b/spectre-meltdown-checker.sh @@ -730,7 +730,7 @@ check_variant2() if [ "$opt_verbose" -ge 2 ]; then _verbose_nol "* The kernel has set the spec_ctrl flag in cpuinfo: " if [ "$opt_live" = 1 ]; then - if grep -qw spec_ctrl /proc/cpuinfo; then + if grep ^flags /proc/cpuinfo | grep -qw spec_ctrl; then pstatus green YES else pstatus red NO @@ -766,7 +766,7 @@ check_variant2() # which in that case means ibrs is supported *and* enabled for kernel & user # as per the ibrs patch series v3 if [ "$ibrs_supported" = 0 ]; then - if grep -qw spec_ctrl_ibrs /proc/cpuinfo; then + if grep ^flags /proc/cpuinfo | grep -qw spec_ctrl_ibrs; then _debug "ibrs: found spec_ctrl_ibrs flag in /proc/cpuinfo" ibrs_supported=1 # enabled=2 -> kernel & user @@ -982,6 +982,28 @@ check_variant3() else pstatus blue N/A "can't verify if PTI is enabled in offline mode" fi + + # no security impact but give a hint to the user in verbose mode + # about PCID/INVPCID cpuid features that must be present to avoid + # too big a performance impact with PTI + # refs: + # https://marc.info/?t=151532047900001&r=1&w=2 + # https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU + if [ "$opt_verbose" -ge 2 ]; then + _info "* Performance impact if PTI is enabled" + _info_nol "* CPU supports PCID: " + if grep ^flags /proc/cpuinfo | grep -qw pcid; then + pstatus green YES 'performance degradation with PTI will be limited' + else + pstatus blue NO 'no security impact but performance will be degraded with PTI' + fi + _info_nol "* CPU supports INVPCID: " + if grep ^flags /proc/cpuinfo | grep -qw invpcid; then + pstatus green YES 'performance degradation with PTI will be limited' + else + pstatus blue NO 'no security impact but performance will be degraded with PTI' + fi + fi fi # if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it |