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{
    "id": 2232152,
    "url": "http://patchwork.ozlabs.org/api/1.2/covers/2232152/?format=api",
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    "msgid": "<20260503073541.790215-1-eric.auger@redhat.com>",
    "list_archive_url": null,
    "date": "2026-05-03T07:33:20",
    "name": "[v4,00/17] kvm/arm: Introduce a customizable aarch64 KVM host model",
    "submitter": {
        "id": 69187,
        "url": "http://patchwork.ozlabs.org/api/1.2/people/69187/?format=api",
        "name": "Eric Auger",
        "email": "eric.auger@redhat.com"
    },
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/cover/20260503073541.790215-1-eric.auger@redhat.com/mbox/",
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            "date": "2026-05-03T07:33:20",
            "name": "kvm/arm: Introduce a customizable aarch64 KVM host model",
            "version": 4,
            "mbox": "http://patchwork.ozlabs.org/series/502569/mbox/"
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        "From": "Eric Auger <eric.auger@redhat.com>",
        "To": "eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org,\n qemu-arm@nongnu.org, kvmarm@lists.linux.dev, peter.maydell@linaro.org,\n richard.henderson@linaro.org, cohuck@redhat.com, sebott@redhat.com,\n skolothumtho@nvidia.com, philmd@linaro.org",
        "Cc": "maz@kernel.org, oliver.upton@linux.dev, pbonzini@redhat.com,\n armbru@redhat.com, berrange@redhat.com, abologna@redhat.com,\n jdenemar@redhat.com",
        "Subject": "[PATCH v4 00/17] kvm/arm: Introduce a customizable aarch64 KVM host\n model",
        "Date": "Sun,  3 May 2026 09:33:20 +0200",
        "Message-ID": "<20260503073541.790215-1-eric.auger@redhat.com>",
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    },
    "content": "This series enhances the current host KVM model with capability to\nset writable ID reg fields.\n\nSince v6.7 kernel, KVM/arm allows the userspace to overwrite the values\nof a subset of ID regs. The list of writable fields continues to grow.\nThe feature ID range is defined as the AArch64 System register space\nwith op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}.\n\nThe end goal is to get more flexibility when migrating guests\nbetween different host hardware.\n\nQEMU retrieves the writable ID fields from KVM UAPI [1] and\nmatch them against a generated description of ID regs and their\nnamed fields that stem from AARCHMRS Registers.json file.\nCurrent description is based on latest 2026-03 edition.\nThe content of the generated files was compared against kernel\nlinux/arch/arm64/tools/sysreg file [3] . It is not straightforward\nto have unit tests for python scripts as there are many cases for\nfield extraction.\n\nFor each writable named field a uint64 property is created\nfollowing the \"SYSREG_<REG>_<FIELD>\" naming convention. REG and\nFIELD names are those described in ARM ARM Reference manual.\n\nThe list of SYSREG_ID properties can be retrieved through the qmp\nmonitor using query-cpu-model-expansion [2].\n\nConnie & Eric\n\nThis series can be found at:\nhttps://github.com/eauger/qemu/tree/arm-cpu-model-v4\n\nReferences:\n\n[1]\nKVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES\nKVM_ARM_GET_REG_WRITABLE_MASKS\nDocumentation/virt/kvm/api.rst\n\n[2]\nqemu-system-aarch64 -qmp unix:/home/augere/TEST/QEMU/qmp-sock,server,nowait -M virt --enable-kvm -cpu custom\nsudo build/run qmp-shell /home/augere/TEST/QEMU/qmp-sock\nWelcome to the QMP low-level shell!\nConnected to QEMU 11.0.50\n(QEMU) query-cpu-model-expansion type=full model={\"name\":\"host\"}\n\n[3]\nlinux/arch/arm64/tools/sysreg and gen-sysreg.awk\n./tools/include/generated/asm/sysreg-defs.h\n\n\nCornelia Huck (4):\n  target/arm/kvm: Introduce kvm_get_writable_id_regs\n  arm/cpu: accessors for writable id registers\n  arm-qmp-cmds: introspection for ID register props\n  arm/cpu-features: document ID reg properties\n\nEric Auger (13):\n  scripts: introduce scripts/update-aarch64-cpu-sysregs-header.py\n  target/arm/cpu-sysregs.h.inc: Sort by name alphabetical order\n  target/arm/cpu-sysregs.h.inc: Update with automatic generation\n  arm/cpu: Add infra to handle generated ID register definitions\n  scripts: Introduce scripts/aarch64_sysreg_helpers module\n  scripts: Introduce scripts/update-aarch64-cpu-sysreg-properties.py\n  target/arm/cpu-sysreg-properties.c: Generate code with new script\n  arm/kvm: Allow reading all the writable ID registers\n  arm/kvm: write back modified ID regs to KVM\n  target/arm/kvm: Introduce kvm_arm_expose_idreg_properties\n  target/arm/kvm: Special case REVIDR_EL1 and AIDR_EL1\n  target/arm/kvm: Special case ID_AA64ISAR0_EL1 RES0 [24, 27] bits\n  arm/cpu: Expose writable ID reg field properties on the kvm host vcpu\n    model\n\n docs/system/arm/cpu-features.rst              | 104 ++-\n scripts/aarch64_sysreg_helpers.py             | 109 +++\n .../update-aarch64-cpu-sysreg-properties.py   | 169 +++++\n scripts/update-aarch64-cpu-sysregs-header.py  |  51 ++\n target/arm/arm-qmp-cmds.c                     |  19 +\n target/arm/cpu-idregs.h                       |  59 ++\n target/arm/cpu-sysreg-properties.c            | 673 ++++++++++++++++++\n target/arm/cpu-sysregs.h.inc                  |  57 +-\n target/arm/cpu.c                              |  12 +\n target/arm/cpu.h                              |  36 +\n target/arm/cpu64.c                            |  26 +-\n target/arm/kvm-stub.c                         |   3 +-\n target/arm/kvm.c                              | 313 +++++++-\n target/arm/kvm_arm.h                          |  19 +-\n target/arm/meson.build                        |   3 +-\n target/arm/trace-events                       |   6 +\n 16 files changed, 1622 insertions(+), 37 deletions(-)\n create mode 100644 scripts/aarch64_sysreg_helpers.py\n create mode 100644 scripts/update-aarch64-cpu-sysreg-properties.py\n create mode 100755 scripts/update-aarch64-cpu-sysregs-header.py\n create mode 100644 target/arm/cpu-idregs.h\n create mode 100644 target/arm/cpu-sysreg-properties.c"
}