On Wed, Jun 24, 2026 at 09:17:05 +0000, sandesh.patel--- via Devel wrote:
> From: Sandesh Patel <[email protected]>
>
> Unlike x86 boolean CPU features, ARM CPU features are exposed by QEMU
> as multi-bit properties whose accepted values depend on the host; only
> a subset of the possible values are valid on any given host.
>
> A pending QEMU patch series [1] introduces a new QMP command,
> 'query-arm-cpu-props-info', which returns, for each ARM CPU property,
> its type and the set of values supported on the host.
>
> Add support to query feature supported values
>
> [1]
> https://lore.kernel.org/qemu-arm/[email protected]/
>
> Signed-off-by: Sandesh Patel <[email protected]>
> ---
Couple points about capability changes:
> src/qemu/qemu_capabilities.c | 13 +++
> src/qemu/qemu_capabilities.h | 1 +
> src/qemu/qemu_monitor.c | 51 +++++++++++
> src/qemu/qemu_monitor.h | 26 ++++++
> src/qemu/qemu_monitor_json.c | 66 ++++++++++++++
> src/qemu/qemu_monitor_json.h | 5 +
> .../caps_11.1.0_aarch64.replies | 69 ++++++++++++++
> .../caps_11.1.0_aarch64.xml | 1 +
> tests/qemumonitorjsontest.c | 91 +++++++++++++++++++
> 9 files changed, 323 insertions(+)
>
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index a28f87ad2b..cb933aa630 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -767,6 +767,7 @@ VIR_ENUM_IMPL(virQEMUCaps,
>
> /* 495 */
> "blockdev-mirror.target-is-zero", /*
> QEMU_CAPS_BLOCKDEV_MIRROR_TARGET_IS_ZERO */
> + "query-arm-cpu-props-info", /*
> QEMU_CAPS_QUERY_ARM_CPU_PROPS_INFO */
Generally new capability goes in a separate patch to show what it
influences.
> );
>
>
> @@ -812,6 +813,7 @@ struct _virQEMUCapsAccel {
> virQEMUCapsMachineType *machineTypes;
> virQEMUCapsHostCPUData hostCPU;
> qemuMonitorCPUDefs *cpuModels;
> + qemuMonitorCPUPropsInfoList *cpuProps; /* currently only populated on
> ARM + KVM */
> };
>
>
[...]
> diff --git a/tests/qemucapabilitiesdata/caps_11.1.0_aarch64.replies
> b/tests/qemucapabilitiesdata/caps_11.1.0_aarch64.replies
> index 41cd5496c6..40fd157680 100644
> --- a/tests/qemucapabilitiesdata/caps_11.1.0_aarch64.replies
> +++ b/tests/qemucapabilitiesdata/caps_11.1.0_aarch64.replies
> @@ -24932,6 +24932,40 @@
> "in-use",
> "auto"
> ]
> + },
> + {
> + "name": "query-arm-cpu-props-info",
> + "ret-type": "[999]",
> + "meta-type": "command",
> + "arg-type": "0"
> + },
> + {
> + "name": "[999]",
> + "element-type": "999",
> + "meta-type": "array"
> + },
> + {
> + "name": "999",
> + "members": [
> + {
> + "name": "name",
> + "type": "str"
> + },
> + {
> + "name": "type",
> + "type": "str"
> + },
> + {
> + "name": "supported-values",
> + "type": "[str]"
> + },
> + {
> + "name": "composite",
> + "default": null,
> + "type": "str"
> + }
> + ],
> + "meta-type": "object"
> }
> ],
> "id": "libvirt-4"
> @@ -37945,6 +37979,41 @@
> }
> }
>
> +{
> + "execute": "query-arm-cpu-props-info",
> + "id": "libvirt-46"
> +}
> +
> +{
> + "return": [
> + {
> + "name": "hw_prop_WRPs",
> + "supported-values": [
> + "0-3"
> + ],
> + "type": "number"
> + },
> + {
> + "name": "hw_prop_API",
> + "composite": "pauth",
> + "supported-values": [
> + "off"
> + ],
> + "type": "string"
> + },
> + {
> + "name": "feat_RAS",
> + "supported-values": [
> + "0.0",
> + "1.0",
> + "1.1_base"
> + ],
> + "type": "string"
> + }
> + ],
> + "id": "libvirt-46"
> +}
> +
> {
> "execute": "qmp_capabilities",
> "id": "libvirt-1"
Changes to this file *must* be generated from a real qemu using the
dumping tool. Manual change like this are not acceptable.
Also changes to the capability dumps *must* be a separate patch.
The change will also only be accepted once the qemu code hits the
upstream repo. I'm taking care of re-generating this one so once the
corresponding code is upstream feel free to ping me to do a refresh.
In case the CPU I'm generating this on (a raspberry pi 5) doesn't
support what you need you can add another variant of the caps (see the
README in tests/qemucapabilitiesdata). In case you generate that on a
non-released qemu version you'll be also responsible to updating it once
qemu-11.1 is released. Further updates will happen only when you then
contribute another version of said variant once next qemu version is
released.
