The new qemu version works as expected together with 5.4.0-49 kernel required for xsaves
# grep -e 'model name' -e 'flags' /proc/cpuinfo model name : AMD EPYC-Rome Processor flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm rep_good nopl cpuid extd_apicid tsc_known_freq pni pclmulqdq ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm cmp_legacy svm cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw topoext perfctr_core ssbd ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves clzero xsaveerptr wbnoinvd arat npt nrip_save umip rdpid Patches for libvirt are submitted upstream https://www.redhat.com/archives/libvir-list/2020-October/msg00008.html A version fitting for the focal version is attached ** Patch added: "Add-EPYC-ROME-x86-CPU-model.patch" https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1887490/+attachment/5416509/+files/Add-EPYC-ROME-x86-CPU-model.patch -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1887490 Title: Add/Backport EPYC-v3 and EPYC-Rome CPU model Status in libvirt package in Ubuntu: Incomplete Status in linux package in Ubuntu: Invalid Status in qemu package in Ubuntu: Fix Released Status in libvirt source package in Focal: Incomplete Status in linux source package in Focal: Fix Committed Status in qemu source package in Focal: Fix Committed Bug description: ## 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 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1887490/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
