Some Dell systems that use some models of Intel CPUs are susceptible to hangs and system instability during or after microcode update to revision 0xc6/0xca (included as part of microcode-20191113/microcode-20191115 update that addressed CVE-2019-0117, CVE-2019-0123, CVE-2019-11135, and CVE-2019-11139) and/or revision 0xd6 (included as part of microcode-20200609 update that addressed CVE-2020-0543, CVE-2020-0548, and CVE-2020-0549) [1][2][3][4][5][6]. In order to address this, microcode update to the newer revision has been disabled by default on these systems, and the previously published microcode revisions 0xae/0xb4/0xb8 are used by default for the OS-driven microcode update. [1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/23 [2] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/24 [3] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/33 [4] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/34 [5] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/35 [6] https://bugzilla.redhat.com/show_bug.cgi?id=1846097 This caveat contains revision 0xca of 06-[89]e-0x microcode publicly released by Intel; for the latest revision of the microcode files, please refer to caveat 06-8e-9e-0x-dell. For the reference, microarchitectures of the affected CPU models: * Amber Lake-Y * Kaby Lake-G/H/S/U/Y/Xeon E3 * Coffee Lake-H/S/U/Xeon E * Comet Lake-U 4+2 * Whiskey Lake-U Family names of the affected CPU models: * 7th Generation Intel® Core™ Processor Family * 8th Generation Intel® Core™ Processor Family * 9th Generation Intel® Core™ Processor Family * 10th Generation Intel® Core™ Processor Family (selected models) * Intel® Celeron® Processor G Series * Intel® Celeron® Processor 5000 Series * Intel® Core™ X-series Processors (i7-7740X, i5-7640X only) * Intel® Pentium® Gold Processor Series * Intel® Pentium® Processor Series (selected models) * Intel® Xeon® Processor E Family * Intel® Xeon® Processor E3 v6 Family SHA1 checksums of the microcode files containing microcode revisions in question: * 06-8e-09, revision 0xb4: e253c95c29c3eef6576db851dfa069d82a91256f * 06-8e-0a, revision 0xb4: 45bcba494be07df9eeccff9627578095a97fba4d * 06-8e-0b, revision 0xb8: 3e54bf91d642ad81ff07fe274d0cfb5d10d09c43 * 06-8e-0c, revision 0xb8: bf635c87177d6dc4e067ec11e1caeb19d3c325f0 * 06-9e-09, revision 0xb4: 42f68eec4ddb79dd6be0c95c4ce60e514e4504b1 * 06-9e-0a, revision 0xb4: 37c7cb394dd36610b57943578343723da67d50f0 * 06-9e-0b, revision 0xb4: b5399109d0a5ce8f5fb623ff942da0322b438b95 * 06-9e-0c, revision 0xae: 131bce89e4d210de8322ffbc6bd787f1af66a7df * 06-9e-0d, revision 0xb8: 22511b007d1df55558d115abb13a1c23ea398317 * 06-8e-09, revision 0xca: 9afa1bae40995207afef13247f114be042d88083 * 06-8e-0a, revision 0xca: 1d90291cc25e17dc6c36c764cf8c06b41fed4c16 * 06-8e-0b, revision 0xca: 3fb1246a6594eff5e2c2076c63c600d734f10777 * 06-8e-0c, revision 0xca: e871540671f59b4fa5d0d454798f09a4d412aace * 06-9e-09, revision 0xca: b5eed11108ab7ac1e675fe75d0e7454a400ddd35 * 06-9e-0a, revision 0xca: e472304aaa2f3815a32822cb111ab3f43bf3dfe4 * 06-9e-0b, revision 0xca: 78f47c5162da680878ed057dc7c853f9737c524b * 06-9e-0c, revision 0xca: f23848a009928796a153cb9e8f44522136969408 * 06-9e-0d, revision 0xca: c7a3d469469ee828ba9faf91b67af881fceec3b7 * 06-8e-09, revision 0xd6: 2272c621768437d20e602207752201e0966e5a8c * 06-8e-0a, revision 0xd6: 0b145afb88e028e612f04c2a86385e7d7c3fefc4 * 06-8e-0b, revision 0xd6: c3831b05da83be54f3acc451a1bce90f75e2e9e5 * 06-8e-0c, revision 0xd6: 4b8938a93e23f4b5a2d9de40b87f6afcfdc27c05 * 06-9e-09, revision 0xd6: 4bacba8c598508e7dd4e87e179586abe7a1a987f * 06-9e-0a, revision 0xd6: 4c236afeef9f80ff3a286698fe7cef72926722f0 * 06-9e-0b, revision 0xd6: 2f9ab9b2ba29559ce177632281d7290a24fed2ef * 06-9e-0c, revision 0xd6: 4b9059e519bcab6085b6c103f5d99e509fe0b2bb * 06-9e-0d, revision 0xd6: 3a3b7edfd8126bb34b761b46a32102a622047899 Please contact your system vendor for a BIOS/firmware update that contains the latest microcode version. For the information regarding microcode versions required for mitigating specific side-channel cache attacks, please refer to the following knowledge base articles: * CVE-2017-5715 ("Spectre"): https://access.redhat.com/articles/3436091 * CVE-2018-3639 ("Speculative Store Bypass"): https://access.redhat.com/articles/3540901 * CVE-2018-3620, CVE-2018-3646 ("L1 Terminal Fault Attack"): https://access.redhat.com/articles/3562741 * CVE-2018-12130, CVE-2018-12126, CVE-2018-12127, and CVE-2019-11091 ("Microarchitectural Data Sampling"): https://access.redhat.com/articles/4138151 * CVE-2019-0117 (Intel SGX Information Leak), CVE-2019-0123 (Intel SGX Privilege Escalation), CVE-2019-11135 (TSX Asynchronous Abort), CVE-2019-11139 (Voltage Setting Modulation): https://access.redhat.com/solutions/2019-microcode-nov * CVE-2020-0543 (Special Register Buffer Data Sampling), CVE-2020-0548 (Vector Register Data Sampling), CVE-2020-0549 (L1D Cache Eviction Sampling): https://access.redhat.com/solutions/5142751 The information regarding disabling microcode update is provided below. To disable usage of the newer microcode revision for a specific kernel version, please create a file "disallow-intel-06-8e-9e-0x-0xca" inside /lib/firmware/ directory, run "/usr/libexec/microcode_ctl/update_ucode" to update firmware directory used for late microcode updates, and run "dracut -f --kver " so initramfs for this kernel version is regenerated, for example: touch /lib/firmware/3.10.0-862.9.1/disallow-intel-06-8e-9e-0x-0xca /usr/libexec/microcode_ctl/update_ucode dracut -f --kver 3.10.0-862.9.1 To disable usage of the newer microcode revision for all kernels, please create file "/etc/microcode_ctl/ucode_with_caveats/disallow-intel-06-8e-9e-0x-0xca", run "/usr/libexec/microcode_ctl/update_ucode" to update firmware directories used for late microcode updates, and run "dracut -f --regenerate-all" so initramfs images get regenerated, for example: mkdir -p /etc/microcode_ctl/ucode_with_caveats touch /etc/microcode_ctl/ucode_with_caveats/disallow-intel-06-8e-9e-0xca /usr/libexec/microcode_ctl/update_ucode dracut -f --regenerate-all Please refer to /usr/share/doc/microcode_ctl/README.caveats for additional information.