Description

GICv4.1 (Generic Interrupt Controller v4.1) is an enhanced feature of the interrupt controller under the ARM architecture, supporting features such as DirectLPI (Direct Local Peripheral Interrupt) and RVPEID (Revocable Virtual Physical Event ID) in the NVIDIA Grace-Hopper platform. This feature can significantly improve the performance of the virtual machine (KVM) in high-load MSI (Message Signaled Interrupts) scenarios (such as VFIO device transparent transmission) by optimizing the interrupt forwarding mechanism.Hardware support: 

Physical hardware support for GICv4.1 has been implemented on the Grace-Hopper platform, and kernel logs show that GICv4 features have been activated (such as DirectLPI RVPEID Valid+Dirty), but the KVM layer LPI forwarding function is currently disabled by default.

Historical technical obstacles: Due to hardware errata of GICv4 on the Grace platform in 3+ CPU systems, the kvm-arm.vgic_v4_enable=1 configuration was temporarily removed; the upstream has fixed this problem through the quirk patch, allowing the option to be safely enabled.

Current bottleneck: The maturity of the function needs to be verified through systematic testing, and it has not yet been enabled in the production environment kernel.

Goal: Verify the stability of GICv4, include relevant tests in the 10.2 test scope, and decide whether to announce the support of this feature in 10.2 based on the specific test results.