[PATCH v3 0/4] KVM: arm64: Add attribute to control GICD_TYPER2.nASSGIcap

Oliver Upton oliver.upton at linux.dev
Fri Jun 13 13:53:07 PDT 2025


On Fri, Jun 13, 2025 at 03:52:34PM +0000, Raghavendra Rao Ananta wrote:
> A shortcoming of the GIC architecture is that there's an absolute limit on
> the number of vPEs that can be tracked by the ITS. It is possible that
> an operator is running a mix of VMs on a system, only wanting to provide
> a specific class of VMs with hardware interrupt injection support.
> 
> The series introduces KVM_DEV_ARM_VGIC_FEATURE_nASSGIcap vGIC attribute to allow
> the userspace to control GICD_TYPER2.nASSGIcap (GICv4.1) on a per-VM basis.
> 
> v1: https://lore.kernel.org/kvmarm/20250514192159.1751538-1-rananta@google.com/
> 
> v1 -> v2: https://lore.kernel.org/all/20250531012545.709887-1-oliver.upton@linux.dev/
>  - Drop all use of GICv4 in the UAPI and KVM-internal helpers in favor
>    of nASSGIcap. This changes things around to model a guest feature,
>    not a host feature.
> 
>  - Consolidate UAPI into a single attribute and expect userspace to use
>    to read the attribute for discovery, much like we do with the ID
>    registers
> 
>  - Squash documentation together with implementation
> 
>  - Clean up maintenance IRQ attribute handling, which I ran into as part
>    of reviewing this series
> 
> v2 -> v3:
>  - Update checks in vgic-v3.c and vgic-v4.c to also include nASSGIcap (via
>    vgic_supports_direct_sgis()) that's configured by the userspace. (Oliver)
> 
> Oliver Upton (2):
>   KVM: arm64: Disambiguate support for vSGIs v. vLPIs
>   KVM: arm64: vgic-v3: Consolidate MAINT_IRQ handling

Make sure you run checkpatch next time before sending out, it should've
warned you about sending patches w/o including your SOB.

Thanks,
Oliver



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