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78 lines
3.6 KiB
78 lines
3.6 KiB
Intel Broadwell-EP/EX (BDX-ML B/M/R0, family 6, model 79, stepping 1) has issues |
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with microcode update that may lead to a system hang; while some changes |
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to the Linux kernel have been made in an attempt to address these issues, |
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they were not eliminated, so a possibility of unstable system behaviour |
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after a microcode update performed on a running system is still present even |
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on a kernels that contain aforementioned changes. As a result, microcode update |
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for this CPU model has been disabled by default. |
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For the reference, kernel versions for the respective RHEL minor versions |
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that contain the aforementioned changes, are listed below: |
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* Upstream/RHEL 8: kernel-4.17.0 or newer; |
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* RHEL 7.6 onwards: kernel-3.10.0-894 or newer; |
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* RHEL 7.5.z: kernel-3.10.0-862.6.1 or newer; |
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* RHEL 7.4.z: kernel-3.10.0-693.35.1 or newer; |
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* RHEL 7.3.z: kernel-3.10.0-514.52.1 or newer; |
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* RHEL 7.2.z: kernel-3.10.0-327.70.1 or newer. |
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Please contact you system vendor for a BIOS/firmware update that contains |
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the latest microcode version. For the information regarding microcode versions |
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required for mitigating specific side-channel cache attacks, please refer |
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to the following knowledge base articles: |
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* CVE-2017-5715 ("Spectre"): |
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https://access.redhat.com/articles/3436091 |
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* CVE-2018-3639 ("Speculative Store Bypass"): |
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https://access.redhat.com/articles/3540901 |
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* CVE-2018-3620, CVE-2018-3646 ("L1 Terminal Fault Attack"): |
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https://access.redhat.com/articles/3562741 |
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* CVE-2018-12130, CVE-2018-12126, CVE-2018-12127, and CVE-2019-11091 |
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("Microarchitectural Data Sampling"): |
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https://access.redhat.com/articles/4138151 |
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The information regarding enforcing microcode load is provided below. |
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For enforcing addition of this microcode to the firmware directory |
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for a specific kernel, where it is available for a late microcode update, |
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please create a file "force-late-intel-06-4f-01" inside |
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/lib/firmware/<kernel_version> directory and run |
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"/usr/libexec/microcode_ctl/update_ucode": |
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touch /lib/firmware/3.10.0-862.9.1/force-late-intel-06-4f-01 |
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/usr/libexec/microcode_ctl/update_ucode |
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After that, it is possible to perform a late microcode update by executing |
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"/usr/libexec/microcode_ctl/reload_microcode" or by writing value "1" to |
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"/sys/devices/system/cpu/microcode/reload" directly. |
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For enforcing addition of this microcode to firmware directories for all |
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kernels, please create a file |
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"/etc/microcode_ctl/ucode_with_caveats/force-late-intel-06-4f-01" |
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and run "/usr/libexec/microcode_ctl/update_ucode": |
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mkdir -p /etc/microcode_ctl/ucode_with_caveats |
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touch /etc/microcode_ctl/ucode_with_caveats/force-late-intel-06-4f-01 |
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/usr/libexec/microcode_ctl/update_ucode |
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For enforcing early load of this microcode for a specific kernel, please |
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create a file "force-early-intel-06-4f-01" inside |
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"/lib/firmware/<kernel_version>" directory and run |
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"dracut -f --kver <kernel_version>": |
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touch /lib/firmware/3.10.0-862.9.1/force-early-intel-06-4f-01 |
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dracut -f --kver 3.10.0-862.9.1 |
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For enforcing early load of this microcode for all kernels, please |
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create a file "/etc/microcode_ctl/ucode_with_caveats/force-early-intel-06-4f-01" |
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and run dracut -f --regenerate-all: |
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mkdir -p /etc/microcode_ctl/ucode_with_caveats |
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touch /etc/microcode_ctl/ucode_with_caveats/force-early-intel-06-4f-01 |
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dracut -f --regenerate-all |
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If you want to avoid removal of the microcode file during cleanup performed by |
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/usr/libexec/microcode_ctl/update_ucode, please remove the corresponding readme |
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file (/lib/firmware/<kernel_version>/readme-intel-06-4f-01). |
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Please refer to /usr/share/doc/microcode_ctl/README.caveats for additional |
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information.
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