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On Thursday, 7 June 2018 08:37:41 BST zless wrote: |
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> Hello, |
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> |
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> I just finished installing kernel 4.14.48 on two |
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> Intel laptops and I have different results for |
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> |
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> /sys/devices/system/cpu/vulnerabilities/spec_store_bypass |
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> |
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> On one of them it looks nice: |
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> "Mitigation: Speculative Store Bypass disabled via prctl and seccomp" |
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> but on the other it still says "Vulnerable". |
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> |
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> Any idea on what might influence this? The kernel configs are fairly |
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> similar, the only thing that's different is the microcode, which is from |
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> 2017 for the "vulnerable" one. |
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> |
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> Thanks |
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I would think it is cause by the microcode. |
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I have two really old Intel laptops and despite announcements to the contrary |
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I noticed the latest (stable) sys-firmware/intel-microcode-20180527-r1 changed |
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the Intel microcode version being loaded on both PCs, after I rebuilt the |
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kernel (4.9.95) to incorporate it (no initrd on either of them). |
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I see this for Spectre V2 which now includes IBPB and IBRS_FW: |
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$ dmesg | grep Spectre |
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[ 0.011385] Spectre V2 : Mitigation: Full generic retpoline |
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[ 0.011507] Spectre V2 : Spectre v2 mitigation: Enabling Indirect Branch |
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Prediction Barrier |
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[ 0.011645] Spectre V2 : Enabling Restricted Speculation for firmware calls |
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After you updated sys-firmware/intel-microcode did you rebuild and reboot the |
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*rebuilt* kernel on both PCs? |
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PS. For good measure I ran make clean first, but I'm not sure if this affects |
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the firmware. |
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-- |
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Regards, |
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Mick |
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