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https://github.com/speed47/spectre-meltdown-checker
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feat: read/write msr now supports msr-tools or perl as dd fallback
This commit is contained in:
Stéphane Lesimple
parent
f4592bf3a8
commit
ab67a9221d
@ -1499,18 +1499,39 @@ number_of_cpus()
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# $2 - cpu index
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write_msr()
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{
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# _msr must be in hex, in the form 0x1234:
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_msr="$1"
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# cpu index, starting from 0:
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_cpu="$2"
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if [ "$os" != Linux ]; then
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cpucontrol -m "$1=0" "/dev/cpuctl$2" >/dev/null 2>&1; ret=$?
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cpucontrol -m "$_msr=0" "/dev/cpuctl$_cpu" >/dev/null 2>&1; ret=$?
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else
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# for Linux
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# convert to decimal
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_msrindex=$(( $1 ))
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if [ ! -w /dev/cpu/"$2"/msr ]; then
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_msr=$(( _msr ))
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if [ ! -w /dev/cpu/"$_cpu"/msr ]; then
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ret=200 # permission error
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# if wrmsr is available, use it
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elif which wrmsr >/dev/null 2>&1 && [ "$SMC_NO_WRMSR" != 1 ]; then
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_debug "write_msr: using wrmsr"
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wrmsr $_msr 0 2>/dev/null; ret=$?
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# or if we have perl, use it, any 5.x version will work
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elif which perl >/dev/null 2>&1 && [ "$SMC_NO_PERL" != 1 ]; then
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_debug "write_msr: using perl"
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ret=1
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perl -e "open(M,'>','/dev/cpu/$_cpu/msr') and seek(M,$_msr,0) and exit(syswrite(M,pack('H16',0)))"; [ $? -eq 8 ] && ret=0
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# fallback to dd if it supports seek_bytes
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elif dd if=/dev/null of=/dev/null bs=8 count=1 seek="$_msr" oflag=seek_bytes 2>/dev/null; then
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_debug "write_msr: using dd"
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dd if=/dev/zero of=/dev/cpu/"$_cpu"/msr bs=8 count=1 seek="$_msr" oflag=seek_bytes 2>/dev/null; ret=$?
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else
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dd if=/dev/zero of=/dev/cpu/"$2"/msr bs=8 count=1 seek="$_msrindex" oflag=seek_bytes 2>/dev/null; ret=$?
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_debug "write_msr: got no wrmsr, perl or recent enough dd!"
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return 201 # missing tool error
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fi
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fi
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_debug "write_msr: for cpu $2 on msr $1 ($_msrindex), ret=$ret"
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# normalize ret
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[ "$ret" != 0 ] && ret=1
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_debug "write_msr: for cpu $_cpu on msr $_msr, ret=$ret"
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return $ret
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}
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@ -1531,12 +1552,27 @@ read_msr()
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_msr_l="$(( _msr_l >> 24 & 0xFF )) $(( _msr_l >> 16 & 0xFF )) $(( _msr_l >> 8 & 0xFF )) $(( _msr_l & 0xFF ))"
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read_msr_value="$_msr_h $_msr_l"
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else
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# for Linux
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# convert to decimal
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_msr=$(( _msr ))
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if [ ! -r /dev/cpu/"$_cpu"/msr ]; then
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return 200 # permission error
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fi
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# if rdmsr is available, use it
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elif which rdmsr >/dev/null 2>&1 && [ "$SMC_NO_RDMSR" != 1 ]; then
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_debug "read_msr: using rdmsr"
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read_msr_value=$(rdmsr -r $_msr 2>/dev/null | od -t u1 -A n)
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# or if we have perl, use it, any 5.x version will work
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elif which perl >/dev/null 2>&1 && [ "$SMC_NO_PERL" != 1 ]; then
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_debug "read_msr: using perl"
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read_msr_value=$(perl -e "open(M,'<','/dev/cpu/$_cpu/msr') and seek(M,$_msr,0) and read(M,\$_,8) and print" | od -An -t u1)
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# fallback to dd if it supports skip_bytes
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elif dd if=/dev/null of=/dev/null bs=8 count=1 skip="$_msr" iflag=skip_bytes 2>/dev/null; then
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_debug "read_msr: using dd"
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read_msr_value=$(dd if=/dev/cpu/"$_cpu"/msr bs=8 count=1 skip="$_msr" iflag=skip_bytes 2>/dev/null | od -t u1 -A n)
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else
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_debug "read_msr: got no rdmsr, perl or recent enough dd!"
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return 201 # missing tool error
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fi
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if [ -z "$read_msr_value" ]; then
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# MSR doesn't exist, don't check for $? because some versions of dd still return 0!
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return 1
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@ -1569,9 +1605,7 @@ check_cpu()
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pstatus yellow UNKNOWN "is msr kernel module available?"
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else
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# the new MSR 'SPEC_CTRL' is at offset 0x48
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# here we use dd, it's the same as using 'rdmsr 0x48' but without needing the rdmsr tool
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# if we get a read error, the MSR is not there. bs has to be 8 for msr
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# skip=9 because 8*9=72=0x48
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# we check if we have it for all cpus
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val=0
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cpu_mismatch=0
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for i in $(seq 0 "$idx_max_cpu")
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@ -1598,6 +1632,9 @@ check_cpu()
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elif [ $val -eq 200 ]; then
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pstatus yellow UNKNOWN "is msr kernel module available?"
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spec_ctrl_msr=-1
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elif [ $val -eq 201 ]; then
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pstatus yellow UNKNOWN "missing tool, install either msr-tools or perl"
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spec_ctrl_msr=-1
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else
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spec_ctrl_msr=0
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pstatus yellow NO
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@ -1659,8 +1696,7 @@ check_cpu()
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pstatus yellow UNKNOWN "is msr kernel module available?"
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else
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# the new MSR 'PRED_CTRL' is at offset 0x49, write-only
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# here we use dd, it's the same as using 'wrmsr 0x49 0' but without needing the wrmsr tool
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# if we get a write error, the MSR is not there
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# we test if of all cpus
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val=0
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cpu_mismatch=0
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for i in $(seq 0 "$idx_max_cpu")
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@ -1833,8 +1869,7 @@ check_cpu()
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pstatus yellow UNKNOWN "is msr kernel module available?"
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else
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# the new MSR 'ARCH_CAPABILITIES' is at offset 0x10a
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# here we use dd, it's the same as using 'rdmsr 0x10a' but without needing the rdmsr tool
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# if we get a read error, the MSR is not there. bs has to be 8 for msr
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# we check if we have it for all cpus
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val=0
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val_cap_msr=0
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cpu_mismatch=0
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@ -1874,6 +1909,8 @@ check_cpu()
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fi
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elif [ $val -eq 200 ]; then
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pstatus yellow UNKNOWN "is msr kernel module available?"
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elif [ $val -eq 201 ]; then
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pstatus yellow UNKNOWN "missing tool, install either msr-tools or perl"
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else
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pstatus yellow NO
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fi
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