From ff2aa6495d4beafa84cfdd8c61fc00785fee3d9a Mon Sep 17 00:00:00 2001 From: Sascha Bischoff Date: Fri, 27 Jun 2025 10:09:02 +0000 Subject: [PATCH] KVM: arm64: gic-v5: Probe for GICv5 Add in a probe function for GICv5 which enables support for GICv3 guests on a GICv5 host, if FEAT_GCIE_LEGACY is supported by the hardware. Co-authored-by: Timothy Hayes Signed-off-by: Timothy Hayes Signed-off-by: Sascha Bischoff Link: https://lore.kernel.org/r/20250627100847.1022515-6-sascha.bischoff@arm.com Signed-off-by: Oliver Upton --- arch/arm64/kvm/Makefile | 3 +- arch/arm64/kvm/vgic/vgic-init.c | 3 ++ arch/arm64/kvm/vgic/vgic-v5.c | 52 +++++++++++++++++++++++++++++++++ arch/arm64/kvm/vgic/vgic.h | 2 ++ 4 files changed, 59 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/kvm/vgic/vgic-v5.c diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 7c329e01c557a..3ebc0570345cc 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -23,7 +23,8 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \ vgic/vgic-v3.o vgic/vgic-v4.o \ vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \ vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \ - vgic/vgic-its.o vgic/vgic-debug.o vgic/vgic-v3-nested.o + vgic/vgic-its.o vgic/vgic-debug.o vgic/vgic-v3-nested.o \ + vgic/vgic-v5.o kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o kvm-$(CONFIG_ARM64_PTR_AUTH) += pauth.o diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index 1f1f0c9ce64fa..72442c825d199 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -724,6 +724,9 @@ int kvm_vgic_hyp_init(void) kvm_info("GIC system register CPU interface enabled\n"); } break; + case GIC_V5: + ret = vgic_v5_probe(gic_kvm_info); + break; default: ret = -ENODEV; } diff --git a/arch/arm64/kvm/vgic/vgic-v5.c b/arch/arm64/kvm/vgic/vgic-v5.c new file mode 100644 index 0000000000000..6bdbb221bcde7 --- /dev/null +++ b/arch/arm64/kvm/vgic/vgic-v5.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include + +#include "vgic.h" + +/* + * Probe for a vGICv5 compatible interrupt controller, returning 0 on success. + * Currently only supports GICv3-based VMs on a GICv5 host, and hence only + * registers a VGIC_V3 device. + */ +int vgic_v5_probe(const struct gic_kvm_info *info) +{ + u64 ich_vtr_el2; + int ret; + + if (!info->has_gcie_v3_compat) + return -ENODEV; + + kvm_vgic_global_state.type = VGIC_V5; + kvm_vgic_global_state.has_gcie_v3_compat = true; + + /* We only support v3 compat mode - use vGICv3 limits */ + kvm_vgic_global_state.max_gic_vcpus = VGIC_V3_MAX_CPUS; + + kvm_vgic_global_state.vcpu_base = 0; + kvm_vgic_global_state.vctrl_base = NULL; + kvm_vgic_global_state.can_emulate_gicv2 = false; + kvm_vgic_global_state.has_gicv4 = false; + kvm_vgic_global_state.has_gicv4_1 = false; + + ich_vtr_el2 = kvm_call_hyp_ret(__vgic_v3_get_gic_config); + kvm_vgic_global_state.ich_vtr_el2 = (u32)ich_vtr_el2; + + /* + * The ListRegs field is 5 bits, but there is an architectural + * maximum of 16 list registers. Just ignore bit 4... + */ + kvm_vgic_global_state.nr_lr = (ich_vtr_el2 & 0xf) + 1; + + ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V3); + if (ret) { + kvm_err("Cannot register GICv3-legacy KVM device.\n"); + return ret; + } + + static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif); + kvm_info("GCIE legacy system register CPU interface\n"); + + return 0; +} diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index 23d3939980856..4f1e123b063e2 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -308,6 +308,8 @@ int vgic_init(struct kvm *kvm); void vgic_debug_init(struct kvm *kvm); void vgic_debug_destroy(struct kvm *kvm); +int vgic_v5_probe(const struct gic_kvm_info *info); + static inline int vgic_v3_max_apr_idx(struct kvm_vcpu *vcpu) { struct vgic_cpu *cpu_if = &vcpu->arch.vgic_cpu; -- 2.47.2