Scripts to extract data from a QEMU binary and compare machine- type compatibility between different QEMU binaries.
To validate a qemu-system-x86_64 binary in your system against reference
dumps, you can run:
./compat_check.py /usr/bin/qemu-system-x86_64 -O dump.json
./validate.sh dump.json
The first command will extract all info from the QEMU binary using QMP commands and GDB. The second command will compare the extracted dump against the existing reference dumps in this repository.
The scripts in this repository use GDB to extract information that is not provided through QMP commands. In other words, this is a workaround to limitations in the QMP introspection interfaces provided by QEMU.
There are a few errors reported on the x86 CPU min-*level properties that are
likely to be false positives. This needs to be investigated.
The scripts doesn't know what to expect on properties that were not present
in older QEMU versions, and prints "I don't know the default value of ..."
warnings. This can be addressed by adding new entires to OMITTED_PROP_VALUES.
To collect data from a single QEMU binary and save it in a JSON
dump, use the -O option. e.g.:
$ ./compat_checker.py /usr/bin/qemu-system-x86_64 -O qemu-raw-data.json
After you collected data from different QEMU versions, you can compare all machine-types in both dumps. e.g.:
$ ./compat_checker.py dump1.json dump2.json
You can also compare multiple QEMU binaries directly. e.g.:
$ ./compat_checker.py /path/to/build1/qemu-system-x86_64 /path/to/build2/qemu-system-x86_64
Or you can compare raw JSON dumps with QEMU binaries. e.g.:
$ ./compat_checker.py dump-from-another-host.json /usr/bin/qemu-system-x86_64
If you want to test the gdb-extract-qemu-info.py gdb script, run
the script using gdb -P. e.g.:
$ gdb -q -P gdb-extract-qemu-info.py ~/rh/proj/virt/qemu/x86-kvm-build/x86_64-softmmu/qemu-system-x86_64 --device x86_64-cpu --machine pc
[{"result": {"fw_name": null, "vmsd": null, "unrealize": "0x555555686125 <device_unrealize>", "reset": null, "unplug": null, "realize": "0x555555869867 <x86_cpu_realizefn>", "exit": null, "cannot_instantiate_with_device_add_yet": true, "props": [{"arrayoffset": 0, "qtype": 6, "arrayfieldsize": 0, "name": "pmu", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "boolean"}, "bitnr": 0, "arrayinfo": null, "offset": 69576, "defval": false}, {"arrayoffset": 0, "qtype": 0, "arrayfieldsize": 0, "name": "hv-spinlocks", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "int"}, "bitnr": 0, "arrayinfo": null, "offset": 0}, {"arrayoffset": 0, "qtype": 6, "arrayfieldsize": 0, "name": "hv-relaxed", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "boolean"}, "bitnr": 0, "arrayinfo": null, "offset": 69521, "defval": false}, {"arrayoffset": 0, "qtype": 6, "arrayfieldsize": 0, "name": "hv-vapic", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "boolean"}, "bitnr": 0, "arrayinfo": null, "offset": 69520, "defval": false}, {"arrayoffset": 0, "qtype": 6, "arrayfieldsize": 0, "name": "hv-time", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "boolean"}, "bitnr": 0, "arrayinfo": null, "offset": 69528, "defval": false}, {"arrayoffset": 0, "qtype": 6, "arrayfieldsize": 0, "name": "check", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "boolean"}, "bitnr": 0, "arrayinfo": null, "offset": 69529, "defval": false}, {"arrayoffset": 0, "qtype": 6, "arrayfieldsize": 0, "name": "enforce", "info": {"enum_table": null, "parse": null, "print": null, "release": null, "legacy_name": null, "name": "boolean"}, "bitnr": 0, "arrayinfo": null, "offset": 69530, "defval": false}], "bus_type": "icc-bus", "init": null, "desc": null}, "request": ["query-device-type", "x86_64-cpu"]}, {"result": {"boot_order": "cad", "no_parallel": 0, "default_machine_opts": "firmware=bios-256k.bin", "use_virtcon": 0, "desc": "RHEL 7.0.0 PC (i440FX + PIIX, 1996)", "no_cdrom": 0, "max_cpus": 240, "no_floppy": 0, "no_sdcard": 0, "reset": null, "name": "pc-i440fx-rhel7.0.0", "no_serial": 0, "is_default": 1, "alias": "pc", "use_sclp": 0, "hw_version": null, "compat_props": []}, "request": ["query-machine", "pc"]}]
$
Running ./compat_checker.py A B checks if B can emulate A properly (for
example, limits like max_cpus can be larger on B).