** Description changed: SRU Justification: [Impact] Google has requested these upstream commits be applied in order to fix bugs preventing the boot of 5.15 kernel instances on their Intel TDX enabled infrastructure. These patches aim to resolve problems with incorrect assessment of the CPU's address width in bits on x86, mostly during boot. [Fix] Google recommended the patchset: 6890cb1ace35 x86/cpu/intel: Detect TME keyid bits before setting MTRR mask registers 9a458198eba9 x86/cpu: Allow reducing x86_phys_bits during early_identify_cpu() f6b980646b93 x86/mtrr: Remove physical address size calculation And of these, only the first is already present in the Jammy 5.15 kernel. [Test Plan] Google reported inability to boot Focal images (which use this kernel) on a specific configuration in a deployment zone where Intel TDX was enabled. This patchset can be tested by booting a Jammy image on one such machine (which uses the 6.8 kernel), installing this patched kernel, and booting into it. [Where problems could occur] As these changes affect booting and the kernel's understanding of the cpu, an error in the backporting of these patches could cause the user to be unable to boot the kernel. Risk of an error is relatively low due to the first patch applying cleanly and the second patch only needing modification in the MTRR cleanup feature, which could be disabled with a kernel command line parameter. If the fixes don't work, we would see the kernel continue to not be bootable on TDX-enabled hosts. + + [Other] + + SF: #00406009
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2097811 Title: Fix bugs preventing boot on Intel TDX-enabled hosts To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2097811/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
