This series enhances the current host KVM model with capability to
set writable ID reg fields.
Since v6.7 kernel, KVM/arm allows the userspace to overwrite the values
of a subset of ID regs. The list of writable fields continues to grow.
The feature ID range is defined as the AArch64 System register space
with op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}.
The end goal is to get more flexibility when migrating guests
between different host hardware.
QEMU retrieves the writable ID fields from KVM UAPI [1] and
match them against a generated description of ID regs and their
named fields that stem from AARCHMRS Registers.json file.
Current description is based on latest 2026-03 edition.
The content of the generated files was compared against kernel
linux/arch/arm64/tools/sysreg file. It is not straightforward
to have unit tests for python scripts as there are many cases for
field extraction.
For each writable named field a uint64 property is created
following the "SYSREG_<REG>_<FIELD>" naming convention. REG and
FIELD names are those described in ARM ARM Reference manual.
The list of SYSREG_ID properties can be retrieved through the qmp
monitor using query-cpu-model-expansion.
Connie & Eric
This series can be found at:
https://github.com/eauger/qemu/tree/arm-cpu-model-v8
History:
--------
v7 -> v8:
- fixed make check errors
- removed demux regs from cpu-sysregs.h.inc
- Proper handling of ValueRange messed up on v7
- removed ArmIdRegArchVal
- introduced kvm_arm_create_scratch_max_host_vcpu and pass
error handle to kvm_arm_create_scratch_host_vcpu()
Cornelia Huck (3):
target/arm/kvm: Retrieve writable ID reg map
arm/cpu-features: document ID reg properties
arm-qmp-cmds: introspection for ID register props
Eric Auger (16):
scripts: introduce scripts/update-aarch64-cpu-sysregs-header.py
target/arm/cpu-sysregs.h.inc: Sort by name alphabetical order
target/arm/cpu-sysregs.h.inc: Update with automatic generation
arm/cpu: Add infra to handle generated ID register definitions
scripts: Introduce scripts/aarch64_sysreg_helpers module
scripts: Introduce scripts/update-aarch64-cpu-sysreg-properties.py
target/arm/cpu-idregs.h.inc: generate with script
target/arm/cpu-idregs.h.inc: Generate enum values
arm/kvm: Initialize all writable ID registers from host
target/arm/kvm: Introduce kvm_arm_expose_idreg_properties
target/arm/cpu: Expose writable ID reg field properties on the kvm
host vcpu model
target/arm/cpu-idregs.h.inc: Generate reserved fields
target/arm/kvm: Ignore and trace unexpected writable reserved fields
target/arm/kvm: add utility to write idregs in scratch vcpu
target/arm/kvm: Add an error handle to
kvm_arm_create_scratch_host_vcpu
kvm: Introduce kvm_arm_create_scratch_max_host_vcpu
Shaju Abraham (1):
target/arm/cpu_idregs: generate tables for Arm64 ID registers and
fields
docs/system/arm/cpu-features.rst | 106 +-
target/arm/cpu-idregs.h | 36 +
target/arm/kvm_arm.h | 36 +-
target/arm/cpu-idregs.h.inc | 2512 +++++++++++++++++
target/arm/cpu-sysregs.h.inc | 55 +-
target/arm/arm-qmp-cmds.c | 73 +
target/arm/cpu-idregs.c | 96 +
target/arm/cpu64.c | 5 +
target/arm/kvm-stub.c | 18 +
target/arm/kvm.c | 480 +++-
scripts/aarch64_sysreg_helpers.py | 121 +
.../update-aarch64-cpu-sysreg-properties.py | 299 ++
scripts/update-aarch64-cpu-sysregs-header.py | 51 +
target/arm/meson.build | 1 +
target/arm/trace-events | 8 +
15 files changed, 3813 insertions(+), 84 deletions(-)
create mode 100644 target/arm/cpu-idregs.h
create mode 100644 target/arm/cpu-idregs.h.inc
create mode 100644 target/arm/cpu-idregs.c
create mode 100644 scripts/aarch64_sysreg_helpers.py
create mode 100644 scripts/update-aarch64-cpu-sysreg-properties.py
create mode 100755 scripts/update-aarch64-cpu-sysregs-header.py
--
2.53.0
