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Mon, 31 Aug 2026 14:48:02 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 31 Aug 2026 14:48:02 +0000 (GMT) From: Steffen Eiden To: kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Cc: Alexander Gordeev , Andreas Grapentin , Arnd Bergmann , Catalin Marinas , Christian Borntraeger , Claudio Imbrenda , David Hildenbrand , Friedrich Welter , Fuad Tabba , Gautam Gala , Hariharan Mari , Heiko Carstens , Hendrik Brueckner , Ilya Leoshkevich , Janosch Frank , Joey Gouly , Marc Zyngier , Nico Boehr , Nina Schoetterl-Glausch , Oliver Upton , Paolo Bonzini , Sean Christopherson , Suzuki K Poulose , Sven Schnelle , Ulrich Weigand , Vasily Gorbik , Will Deacon , Zenghui Yu Subject: [PATCH v7 00/23] KVM: s390: Introduce arm64 KVM Date: Mon, 31 Aug 2026 16:47:37 +0200 Message-ID: <20260831144802.834315-1-seiden@linux.ibm.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: U9iJH5GpMZBhyDvSZcQOu3zNqpv-EbEi X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODMxMDEyNSBTYWx0ZWRfX2FdZg+mmmiW8 1snSfJnACyLd5gKBb7kWThHNPzwNLVG3DGiuS95hqW4+GRei3HzpArUI2SeLlKGvasW1x+PjuQG 2OibgMEINbr++bxNoFXJ3kgxzmH3Tih/91+HrJbMsGQfb6guU9VVt9FuzVLVA6NClH5D9970HWe 5jICdm7o/trAZEn6HH/v5SS14JUEjTO+Aak5hkb5YvGB9Kekys25bDjv06e+jlNGdbWeoh9+5CP 8WiYz6dFHcmW2Bc/McOXXCWyX3DRibqkhtUobzz+0iOBFcesNu8smghmxjI+RA0L78AC+TDg4Ba VAYKMnjzpbCFnfb1eWzMELxW+PWytFxuzUJIarHTehVIGoNfllCwGkSo6Rj/jsTz0nEgoICgWEk LT9YfcIPLOSlLrfR2MBznOtJHC/rNK4WEd1OTw9spwOFuXh9Ssnz7YldhvnTzw+YivPbRBeO2Hs YjC49iL9ETpAst4NYhw== X-Authority-Analysis: v=2.4 cv=Osl/DS/t c=1 sm=1 tr=0 ts=6a959428 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=vZ1yADyhxQgHX5qgNpMA:9 a=O8hF6Hzn-FEA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwODMxMDEyNSBTYWx0ZWRfXxrVmN6qQC9cN qGOnwMP+wbYlgofqW/paHEm1i926paylyw1LBguIDBc0RVbcShvrSnVOq3nE5Gm+PWtx4uumXQr KBoVXBxFw3XO19TmZTm3X03U+hzR9sc= X-Proofpoint-ORIG-GUID: HlFFv_tgqKYXt2H3wDLZie587wPR3J42 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-31_05,2026-08-27_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 malwarescore=0 suspectscore=0 bulkscore=0 lowpriorityscore=0 adultscore=0 impostorscore=0 phishscore=0 clxscore=1015 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608310125 Introduce arm-on-s390. Enable KVM-accelerated ARM CPU virtualisation on s390. For the original, now partially outdated, cover letter, have a look at versions one to three [1]. To share arm64 code with arm-on-s390 KVM, s390 extracts relevant parts of arm64 definitions and implementation and uses them locally. This results in minimal changes to existing arm64 code and headers. To enable s390 to selectively extract relevant definitions while skipping architecture-specific code (e.g., arm64 assembly), a shared marker is introduced. The ARM64_S390_COMMON macro marks regions of arm64 code that are shared with s390: in arch/arm64/kvm/.c #ifdef ARM64_S390_COMMON #endif /* ARM64_S390_COMMON */ ARM64_S390_COMMON is defined for all arm64 compilation units. During the s390 build, an allow-list of arm64 headers is extracted into arch/s390/include/generated/arm64/. If a header contains at least one shared region, only those regions are copied along with the include guard. If no shared region is found, s390 uses the full header, which is copied in its entirety. In such cases, a comment is added at the top of the header to notify arm64 developers that the file is shared with s390 and changes may impact s390. For C files, the process is similar. Selected KVM/arm64 C files are partially extracted into arch/s390/kvm/arm64/generated/code.inc. The s390 arm64 KVM implementation includes these snippets to reuse arm64 code without changing linkage. The goal is to share as much functionality as possible. Userspace tools requiring KVM/arm64 uapi on s390 must use a vendored KVM API, as s390 will not ship nor install arm64 KVM uapi headers. This approach reduces the churn, especially for arm64 while keeping the maintenance burden low. Series structure A) KVM symbol cleanup and refactoring (patches 1-3): Prepare KVM to support two KVM modules in parallel (spin-off: [5]). Clean up KVM module symbol exports, making it possible to load two KVM modules side by side. Make the KVM device name configurable and allow KVM implementations to disable MMIO regardless of CONFIG_KVM_MMIO. B) Arm64 header and code sharing preparation (patches 4-11): Mark shareable parts with ARM64_S390_COMMON. But first perform minor refactoring to ease integration into s390. All the refactoring/cleanup/fix patches could be picked before the actual share-marker commits (10/11) C) Code sharing infrastructure for s390 (patches 12 & 13): Add Makefile and scripts to extract and build arm64 headers and code for use by s390. D) KVM on s390 (patches 14-23): Introduce the SAE (Start Arm Execution) instruction as the s390 mechanism for running arm64 guests. Build up the new kvm-arm64 module incrementally. A, B, and C could be picked individually without requiring the others so they could go through different trees if required. D obviously requires A-C. Based on v7.3-rc1. Steffen Changes from v6 [4]: - Fix vfio <-> kvm keepalive - add Reviewed-bys and ACKs arm64: - fix SPSR_ELx description - use kvm_arch_flag_bits enum instead of multiple defines - minor requested changes s390: - fix various smaller issues - removed picked s390 refactoring patches (thanks Christian) Changes from v5 [3]: - fix multiple rcu and use after free issues in vfio - multiple smaller mostly cosmetic improvements arm64: - fixed regression in compat enum & cleaned up - fixed SPSR_ELx definitions - removed reset_core_reg extracting which is now is already done (thanks Fuad) - renamed and moved register access function to vcpu_ to kvm_emulate.h they are now at the same position and naming scheme like the preexisting ones - fix resetting reserved field in fpsimd s390: - gmap: Guard and not move s390-guest only gmap-code - split refactoring into more patches to ease review - fixed minor bugs in header/code shared code generation - Kconfig reorganization: - removed KVM_S390, the KVM for s390 guests keeps using by CONFIG_KVM - KVM_ARM64 now depends on KVM - KVM is selectable (as it was before this series) - All (s390) KVM configs are in arch/s390/kvm/Kconfig Changes from v4 [2]: - do not remove CONFIG_KVM_MMIO but let KVM/s390 opt out of MMIO - use kstrdup_const for copying the kvm-device name - use file based vfio tracking instead of inlining struct kvm refcounting arm64: - reorganized arm64 code share & refactoring - first refactoring then sharing - add arm64 refactoring to reduce shared regions - shared a bit more function (definitions) to reduce no of shared regions (which would be shared in later series anyways) - add patch to generate SPSR sysreg definitions - add patch which defines an enum for the arm32 compat registers s390: - fix arm64 header generation wiring - awk scripts are more robust and error out if an end marker is missing - postfix combined headers with -gen instead of -part - removed pre-fault-memory implementation - implemented system supported feature sanitisation - removed some unnecessary functions - moved prefix, cmma, and storage key code from gmap to kvm/s390 - properly reset vxregs Changes from v3 - Complete rework of the code sharing approach - Introduced ARM64_S390_COMMON marker for selective extraction - Build-time extraction instead of development-time sharing - Minimal impact on arm64 codebase - Improved gmap refactoring and integration [1] Previous versions: v1 https://lore.kernel.org/all/20260402042125.3948963-1-seiden@linux.ibm.com/ v2 https://lore.kernel.org/all/20260428155622.1361364-1-seiden@linux.ibm.com/ v3 https://lore.kernel.org/all/20260529155050.2902245-1-seiden@linux.ibm.com/ [2] https://lore.kernel.org/all/20260706085229.979525-1-seiden@linux.ibm.com/ [3] https://lore.kernel.org/all/20260731130902.654679-1-seiden@linux.ibm.com/ [4] https://lore.kernel.org/all/20260812153631.3376090-1-seiden@linux.ibm.com/ [5] https://lore.kernel.org/all/20260812-vfio-v1-1-5cfe0b1fa4e7@linux.ibm.com Hendrik Brueckner (1): s390/hwcaps: Report SAE support as hwcap Steffen Eiden (22): vfio: Use file-based reference counting for KVM KVM: Make device name configurable KVM: Allow KVM implementations to switch off MMIO independent of Kconfig arm64: Use proper include variant arm64: ptrace: Use constants for compat register numbers arm64: sysreg: Convert SPSR_ELx to automatic register generation KVM: arm64: Access elements of vcpu_gp_regs individually KVM: arm64: Use accessor functions for core regs arm64: Prepare sharing arm64 headers with s390 arm64: Share arm64 headers with s390 KVM: arm64: Share arm64 code with s390 s390/tools: Use arm64 headers KVM: s390: Use arm64 code KVM: s390: Prepare KVM/s390 for a second KVM module s390: Introduce Start Arm Execution instruction KVM: s390: arm64: Introduce host definitions KVM: s390: Add basic arm64 kvm module KVM: s390: arm64: Implement required functions KVM: s390: arm64: Implement vm/vcpu create destroy. KVM: s390: arm64: Implement vCPU IOCTLs KVM: s390: arm64: Implement basic page fault handler KVM: s390: arm64: Add KVM_S390_ARM64 Kconfig and Makefile MAINTAINERS | 1 + arch/arm64/Makefile | 5 + arch/arm64/include/asm/brk-imm.h | 1 + arch/arm64/include/asm/esr.h | 5 +- arch/arm64/include/asm/kvm_arm.h | 6 +- arch/arm64/include/asm/kvm_emulate.h | 69 +- arch/arm64/include/asm/kvm_host.h | 117 +-- arch/arm64/include/asm/ptrace.h | 64 +- arch/arm64/include/asm/sysreg.h | 22 +- arch/arm64/kvm/arm.c | 3 + arch/arm64/kvm/guest.c | 22 +- arch/arm64/kvm/handle_exit.c | 6 + arch/arm64/kvm/hyp/exception.c | 4 +- arch/arm64/kvm/hyp/include/hyp/adjust_pc.h | 4 +- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 +- arch/arm64/kvm/mmio.c | 2 + arch/arm64/tools/sysreg | 51 ++ arch/s390/configs/debug_defconfig | 1 + arch/s390/configs/defconfig | 1 + arch/s390/include/arm64/kvm_emulate.h | 130 ++++ arch/s390/include/arm64/kvm_nested.h | 11 + arch/s390/include/arm64/ptrace.h | 11 + arch/s390/include/arm64/sysreg.h | 13 + arch/s390/include/asm/Kbuild | 3 + arch/s390/include/asm/asm-prototypes.h | 1 + arch/s390/include/asm/elf.h | 2 + arch/s390/include/asm/kvm.h | 6 + arch/s390/include/asm/kvm_host.h | 9 + arch/s390/include/asm/kvm_host_arm64.h | 211 ++++++ arch/s390/include/asm/kvm_host_arm64_types.h | 118 +++ arch/s390/include/asm/kvm_host_s390.h | 1 + arch/s390/include/asm/kvm_host_types.h | 4 + arch/s390/include/asm/sae.h | 57 ++ arch/s390/include/asm/sclp.h | 5 +- arch/s390/include/asm/stacktrace.h | 5 + arch/s390/kernel/asm-offsets.c | 1 + arch/s390/kernel/entry.S | 22 + arch/s390/kernel/processor.c | 3 + arch/s390/kvm/Kconfig | 29 + arch/s390/kvm/Makefile | 1 + arch/s390/kvm/arm64/.gitignore | 2 + arch/s390/kvm/arm64/Makefile | 91 +++ arch/s390/kvm/arm64/Makefile.gen | 27 + arch/s390/kvm/arm64/arm.c | 758 +++++++++++++++++++ arch/s390/kvm/arm64/arm.h | 61 ++ arch/s390/kvm/arm64/copy-arm64c.awk | 72 ++ arch/s390/kvm/arm64/guest.c | 135 ++++ arch/s390/kvm/arm64/handle_exit.c | 131 ++++ arch/s390/kvm/arm64/handle_exit.h | 9 + arch/s390/kvm/arm64/inject_fault.c | 21 + arch/s390/kvm/arm64/mmio.c | 15 + arch/s390/kvm/arm64/mmu.c | 177 +++++ arch/s390/kvm/arm64/reset.c | 71 ++ arch/s390/kvm/arm64/trace.h | 42 + arch/s390/kvm/gmap/faultin.c | 5 + arch/s390/kvm/gmap/gmap.c | 4 + arch/s390/kvm/gmap/kvm_mmu.c | 4 + arch/s390/kvm/gmap/trace_gmap.h | 17 + arch/s390/kvm/s390/s390.c | 8 + arch/s390/tools/Makefile | 9 +- arch/s390/tools/Makefile.arm64h | 56 ++ arch/s390/tools/copy-arm64h-full.awk | 47 ++ arch/s390/tools/copy-arm64h.awk | 72 ++ arch/s390/tools/opcodes.txt | 3 + arch/x86/include/asm/kvm_page_track.h | 8 +- arch/x86/kvm/Makefile | 5 +- arch/x86/kvm/mmu/page_track.c | 20 +- drivers/s390/char/sclp_early.c | 1 + drivers/s390/crypto/vfio_ap_ops.c | 20 +- drivers/vfio/group.c | 11 +- drivers/vfio/pci/vfio_pci_zdev.c | 8 +- drivers/vfio/vfio.h | 10 +- drivers/vfio/vfio_main.c | 57 +- include/linux/kvm_host.h | 12 +- include/linux/vfio.h | 5 +- virt/kvm/async_pf.c | 13 +- virt/kvm/async_pf.h | 4 +- virt/kvm/coalesced_mmio.c | 4 + virt/kvm/coalesced_mmio.h | 2 +- virt/kvm/kvm_main.c | 70 +- virt/kvm/vfio.c | 13 +- 81 files changed, 2930 insertions(+), 201 deletions(-) create mode 100644 arch/s390/include/arm64/kvm_emulate.h create mode 100644 arch/s390/include/arm64/kvm_nested.h create mode 100644 arch/s390/include/arm64/ptrace.h create mode 100644 arch/s390/include/arm64/sysreg.h create mode 100644 arch/s390/include/asm/kvm.h create mode 100644 arch/s390/include/asm/kvm_host_arm64.h create mode 100644 arch/s390/include/asm/kvm_host_arm64_types.h create mode 100644 arch/s390/include/asm/sae.h create mode 100644 arch/s390/kvm/arm64/.gitignore create mode 100644 arch/s390/kvm/arm64/Makefile create mode 100644 arch/s390/kvm/arm64/Makefile.gen create mode 100644 arch/s390/kvm/arm64/arm.c create mode 100644 arch/s390/kvm/arm64/arm.h create mode 100644 arch/s390/kvm/arm64/copy-arm64c.awk create mode 100644 arch/s390/kvm/arm64/guest.c create mode 100644 arch/s390/kvm/arm64/handle_exit.c create mode 100644 arch/s390/kvm/arm64/handle_exit.h create mode 100644 arch/s390/kvm/arm64/inject_fault.c create mode 100644 arch/s390/kvm/arm64/mmio.c create mode 100644 arch/s390/kvm/arm64/mmu.c create mode 100644 arch/s390/kvm/arm64/reset.c create mode 100644 arch/s390/kvm/arm64/trace.h create mode 100644 arch/s390/tools/Makefile.arm64h create mode 100644 arch/s390/tools/copy-arm64h-full.awk create mode 100644 arch/s390/tools/copy-arm64h.awk base-commit: cee9395acd8043be0644b25c34bfa86623f2b935 -- 2.53.0