KVM needs to interact with the host IRS in order to, for example, make VMs or VPEs valid. There are two potential approaches here. Either the host irqchip driver can provide an interface, or KVM can interact directly with the host IRS. The latter of these two is chosen as the set of MMIO registers that KVM needs to interact with is orthogonal to the set used by the host irqchip driver (with the exception of some of the read-only IRS_IDRx registers). Pass KVM a pointer to an IRS config frame - the config frame belonging to ANY IRS is fine as long as one IRS's config frame is used consistently - in struct gic_kvm_info. Additionally, include a flag telling KVM whether the IRS is coherent or non-coherent in order to make sure that KVM can do the correct cache state management, if required. Only OF (Device Tree) is supported with this change. ACPI is not. Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com> Link: https://patch.msgid.link/20260904113404.4051341-3-sascha.bischoff@arm.com Signed-off-by: Marc Zyngier <maz@kernel.org>