GICv4.1 Overcommitment Optimization

Generic interrupt controller v4.1 (GICv4.1) is an advanced interrupt controller architecture for Arm servers. It supports virtual locality-specific peripheral interrupts (vLPIs), hardware-accelerated virtual machine (VM) interrupt injection, and interrupt priority management, significantly improving interrupt processing efficiency and scalability in virtualization scenarios. When physical machine (PM) resources are limited and VM overcommitment is used, the GIC needs to use the VMOVP instructions to maintain the mapping between vCPUs and physical CPUs. The VMOVP instructions are executed on the GIC hardware in serial mode, which deteriorates the VM service performance. The GICv4.1 overcommitment optimization feature allows the GIC to skip VMOVP instructions when vCPUs are migrated between CPUs that share the same virtual processing element (vPE) table, thus improving VM service performance in overcommitment scenarios.