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

Oliver Upton
2025-06-13T20:53:22Z

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