** Description changed: + ## Qemu SRU ## + + [Impact] + + * CPU definitions are added to qemu as these CPUs are known. + And due to that over time are missing in former releases. + + * To really benefit from the new features of these chips + they have to be known, therefore new type additions done by + upstream should be backported if they generally apply and do + not depend on SRU-critical changes. + + * This backports two upstream fixes that just add definitions (no + control flow changes) + + [Test Case] + + * Probe qemu for the known CPU types (works on all HW) + $ qemu-system-x86_64 -cpu ? | grep EPYC + Focal without fix: + x86 EPYC (alias configured by machine type) + x86 EPYC-IBPB (alias of EPYC-v2) + x86 EPYC-v1 AMD EPYC Processor + x86 EPYC-v2 AMD EPYC Processor (with IBPB) + Focal with fix also adds: + x86 EPYC-Rome (alias configured by machine type) + x86 EPYC-Rome-v1 AMD EPYC-Rome Processor + x86 EPYC-v3 AMD EPYC Processor + + * Given such HW is available start a KVM guest using those new types + Since we don't have libvirt support (yet) do so directly in qemu + commandline like (bootloader is enough) + $ qemu-system-x86_64 -cpu EPYC-Rome -machine pc-q35-focal,accel=kvm -nographic + $ qemu-system-x86_64 -cpu EPYC-v3 -machine pc-q35-focal,accel=kvm -nographic + + [Regression Potential] + + * This adds new CPU types to the list of known CPUs defining their name + and features. Generally the changes are contained to those new types + and only active when selected - and usually only selectable on such new + machines. Therefore not a lot should change for other users. + One thing thou, if a user selected an unversioned type (which in this + case only can be "EPYC") by default it will pick the latest subversion + that applies. In this case the behavior will change and pick EPYC-v3 + after the fix. But this is the whole purpose of versioned (stay as is) + and unversioned (move with updates) CPU types - so that should be ok. + The EPYC-Rome type didn't exist in Focal before, so it can't "change" + for users. + + + [Other Info] + + * Depends on the new kernel 5.4.0-49 or later (Currently in + focal-proposed) + + --- + Qemu in focal has already support for most (except amd-stibp) flags of this model. Please backport the following patches: https://github.com/qemu/qemu/commit/a16e8dbc043720abcb37fc7dca313e720b4e0f0c https://github.com/qemu/qemu/commit/143c30d4d346831a09e59e9af45afdca0331e819
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1887490 Title: Add/Backport EPYC-v3 and EPYC-Rome CPU model To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1887490/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs