[Bug 2153159] Re: [Ubuntu 26.04] KVM: IBM Test Accelerator for Z (TAZ) not working properly

Thanks for reporting. Patchset sent to KTML: https://lists.ubuntu.com/archives/kernel-team/2026-May/168102.html -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2153159 Title: [Ubuntu 26.04] KVM: IBM Test Accelerator for Z (TAZ) not working properly Status in linux package in Ubuntu: Invalid Status in linux source package in Resolute: In Progress Bug description: [ Impact ] Enable IBM Test Accelerator for Z. [ Fix ] Backport the following patches from upstream: - 2623c96f1172 KVM: s390: only deliver service interrupt with payload - b0ad874d9852 KVM: s390: vsie: Allow non-zarch guests - a9640e2eb711 KVM: s390: vsie: Disable some bits when in ESA mode - c0dcada088ff KVM: s390: vsie: Accommodate ESA prefix pages - 4aebd7d5c72f KVM: s390: Add KVM capability for ESA mode guests [ Test Plan ] Launch a TAZ instance and confirm it can start and run ESA mode nested guests without generating program exceptions in either the TAZ instance or its guests. [ Regression Potential] While the ESA mode enablement is fully opt-in and poses no risk to existing workloads, the prefix bitfield adjustment and the suppression of zero-payload SCLP interrupts are global changes affecting all KVM/s390 guests. Either could impact existing z/Architecture guests. --- On Ubuntu 26.04, the IBM Test Accelerator for Z (TAZ) is not working, i.e. it results in program exceptions within the TAZ instance and/or the guests within it. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2153159/+subscriptions