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https://github.com/speed47/spectre-meltdown-checker
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Check MSR in each CPU/Thread (#136)
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Alex
Stéphane Lesimple
parent
12ea49fe0c
commit
ecdc448531
@ -1059,6 +1059,38 @@ sys_interface_check()
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return 0
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}
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number_of_cpus()
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{
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n=$(grep -c ^processor /proc/cpuinfo)
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return "$n"
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}
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# $1 - msr number
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# $2 - cpu index
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check_msr_enable()
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{
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dd if=/dev/cpu/"$2"/msr of=/dev/null bs=8 count=1 skip="$1" iflag=skip_bytes 2>/dev/null; ret=$?
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return $ret
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}
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# $1 - msr number
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# $2 - cpu index
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# $3 - value
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write_to_msr()
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{
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$echo_cmd -ne "$3" | dd of=/dev/cpu/"$2"/msr bs=8 count=1 seek="$1" oflag=seek_bytes 2>/dev/null; ret=$?
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return $ret
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}
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# $1 - msr number
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# $2 - cpu index
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read_msr()
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{
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msr=$(dd if=/dev/cpu/"$2"/msr bs=8 count=1 skip="$1" iflag=skip_bytes 2>/dev/null | od -t u1 -A n | awk '{print $8}');
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return "$msr"
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}
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check_cpu()
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{
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_info "\033[1;34mHardware check\033[0m"
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@ -1066,6 +1098,9 @@ check_cpu()
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_info "* Hardware support (CPU microcode) for mitigation techniques"
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_info " * Indirect Branch Restricted Speculation (IBRS)"
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_info_nol " * SPEC_CTRL MSR is available: "
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number_of_cpus
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ncpus=$?
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idx_max_cpu=$((ncpus-1))
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if [ ! -e /dev/cpu/0/msr ]; then
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# try to load the module ourselves (and remember it so we can rmmod it afterwards)
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load_msr
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@ -1078,10 +1113,30 @@ check_cpu()
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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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dd if=/dev/cpu/0/msr of=/dev/null bs=8 count=1 skip=9 2>/dev/null; ret=$?
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if [ $ret -eq 0 ]; then
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spec_ctrl_msr=1
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pstatus green YES
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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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do
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check_msr_enable 72 "$i"
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ret=$?
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if [ "$i" -eq 0 ]; then
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val=$ret
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else
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if [ "$ret" -eq $val ]; then
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continue
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else
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cpu_mismatch=1
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fi
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fi
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done
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if [ $val -eq 0 ]; then
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if [ $cpu_mismatch -eq 0 ]; then
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spec_ctrl_msr=1
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pstatus green YES
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else
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spec_ctrl_msr=1
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pstatus green YES "But not in all CPUs"
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fi
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else
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spec_ctrl_msr=0
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pstatus red NO
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@ -1126,15 +1181,34 @@ check_cpu()
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# the new MSR 'PRED_CTRL' is at offset 0x49, write-only
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# here we use dd, it's the same as using 'wrmsr 0x49 0' but without needing the wrmsr tool
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# if we get a write error, the MSR is not there
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$echo_cmd -ne "\0\0\0\0\0\0\0\0" | dd of=/dev/cpu/0/msr bs=8 count=1 seek=73 oflag=seek_bytes 2>/dev/null; ret=$?
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if [ $ret -eq 0 ]; then
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pstatus green YES
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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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do
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write_to_msr 73 "$i" "\0\0\0\0\0\0\0\0"
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ret=$?
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if [ "$i" -eq 0 ]; then
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val=$ret
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else
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if [ "$ret" -eq $val ]; then
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continue
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else
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cpu_mismatch=1
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fi
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fi
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done
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if [ $val -eq 0 ]; then
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if [ $cpu_mismatch -eq 0 ]; then
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pstatus green YES
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else
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pstatus green YES "But not in all CPUs"
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fi
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else
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pstatus red NO
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fi
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fi
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_info_nol " * CPU indicates IBPB capability: "
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# CPUID EAX=0x80000008, ECX=0x00 return EBX[12] indicates support for just IBPB.
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read_cpuid 2147483656 5 16; ret=$?
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@ -1201,16 +1275,40 @@ check_cpu()
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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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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 $8}'); ret=$?
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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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for i in $(seq 0 "$idx_max_cpu")
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do
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check_msr_enable 266 "$i"
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ret=$?
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read_msr 266 "$i"
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capabilities=$?
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if [ "$i" -eq 0 ]; then
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val=$ret
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val_cap_msr=$capabilities
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else
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if [ "$ret" -eq "$val" -a "$capabilities" -eq "$val_cap_msr" ]; then
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continue
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else
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cpu_mismatch=1
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fi
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fi
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done
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capabilities=$val_cap_msr
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capabilities_rdcl_no=0
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capabilities_ibrs_all=0
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if [ $ret -eq 0 ]; then
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if [ $val -eq 0 ]; then
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_debug "capabilities MSR lower byte is $capabilities (decimal)"
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[ $(( capabilities & 1 )) -eq 1 ] && capabilities_rdcl_no=1
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[ $(( capabilities & 2 )) -eq 2 ] && capabilities_ibrs_all=1
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_debug "capabilities says rdcl_no=$capabilities_rdcl_no ibrs_all=$capabilities_ibrs_all"
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if [ "$capabilities_ibrs_all" = 1 ]; then
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pstatus green YES
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if [ $cpu_mismatch -eq 0 ]; then
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pstatus green YES
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else:
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pstatus green YES "But not in all CPUs"
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fi
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else
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pstatus red NO
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fi
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