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fix: report arch_capabilities as NO when no MSR

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When the arch_capabilities MSR is not there, it means
that all the features it might advertise can be considered
as NO instead of UNKNOWN
This commit is contained in:
Stéphane Lesimple
2018-01-26 14:55:01 +01:00
parent 42094c4f8b
commit 0798bd4c5b
1 changed files with 4 additions and 2 deletions
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6
spectre-meltdown-checker.sh
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@@ -1059,6 +1059,8 @@ check_cpu()
if [ "$cpuid_arch_capabilities" = -1 ]; then
pstatus yellow UNKNOWN
elif [ "$cpuid_arch_capabilities" != 1 ]; then
capabilities_rdcl_no=0
capabilities_ibrs_all=0
pstatus red NO
elif [ ! -e /dev/cpu/0/msr ]; then
spec_ctrl_msr=-1
@@ -1068,10 +1070,10 @@ check_cpu()
# here we use dd, it's the same as using 'rdmsr 0x10a' but without needing the rdmsr tool
# if we get a read error, the MSR is not there. bs has to be 8 for msr
capabilities=$(dd if=/dev/cpu/0/msr bs=8 count=1 skip=266 iflag=skip_bytes 2>/dev/null | od -t u1 -A n | awk '{print $8}')
capabilities_rdcl_no=0
capabilities_ibrs_all=0
if [ $? -eq 0 ]; then
_debug "capabilities MSR lower byte is $capabilities (decimal)"
capabilities_rdcl_no=0
capabilities_ibrs_all=0
[ $(( capabilities & 1 )) -eq 1 ] && capabilities_rdcl_no=1
[ $(( capabilities & 2 )) -eq 2 ] && capabilities_ibrs_all=1
_debug "capabilities says rdcl_no=$capabilities_rdcl_no ibrs_all=$capabilities_ibrs_all"