[PATCH v5 02/36] KVM: arm64: vgic: Rework vgic_is_v3() and add vgic_host_has_gicvX()
From: Sascha Bischoff <hidden>
Date: 2026-02-26 15:57:16
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
The GIC version checks used to determine host capabilities and guest configuration have become somewhat conflated (in part due to the addition of GICv5 support). vgic_is_v3() is a prime example, which prior to this change has been a combination of guest configuration and host cabability. Split out the host capability check from vgic_is_v3(), which now only checks if the vgic model itself is GICv3. Add two new functions: vgic_host_has_gicv3() and vgic_host_has_gicv5(). These explicitly check the host capabilities, i.e., can the host system run a GICvX guest or not. The vgic_is_v3() check in vcpu_set_ich_hcr() has been replaced with vgic_host_has_gicv3() as this only applies on GICv3-capable hardware, and isn't strictly only applicable for a GICv3 guest (it is actually vital for vGICv2 on GICv3 hosts). Signed-off-by: Sascha Bischoff <redacted> --- arch/arm64/kvm/sys_regs.c | 2 +- arch/arm64/kvm/vgic/vgic-v3.c | 2 +- arch/arm64/kvm/vgic/vgic.h | 17 +++++++++++++---- 3 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b4e78958ede12..270f1c927c35b 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c@@ -1982,7 +1982,7 @@ static u64 sanitise_id_aa64pfr0_el1(const struct kvm_vcpu *vcpu, u64 val) val |= SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, CSV3, IMP); } - if (vgic_is_v3(vcpu->kvm)) { + if (vgic_host_has_gicv3()) { val &= ~ID_AA64PFR0_EL1_GIC_MASK; val |= SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, GIC, IMP); }
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 386ddf69a9c51..7fc2e0deccff2 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c@@ -499,7 +499,7 @@ void vcpu_set_ich_hcr(struct kvm_vcpu *vcpu) { struct vgic_v3_cpu_if *vgic_v3 = &vcpu->arch.vgic_cpu.vgic_v3; - if (!vgic_is_v3(vcpu->kvm)) + if (!vgic_host_has_gicv3()) return; /* Hide GICv3 sysreg if necessary */
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index c9b3bb07e483c..0bb8fa10bb4ef 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h@@ -454,15 +454,24 @@ void vgic_v3_put_nested(struct kvm_vcpu *vcpu); void vgic_v3_handle_nested_maint_irq(struct kvm_vcpu *vcpu); void vgic_v3_nested_update_mi(struct kvm_vcpu *vcpu); -static inline bool vgic_is_v3_compat(struct kvm *kvm) +static inline bool vgic_is_v3(struct kvm *kvm) +{ + return kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3; +} + +static inline bool vgic_host_has_gicv3(void) { - return cpus_have_final_cap(ARM64_HAS_GICV5_CPUIF) && + /* + * Either the host is a native GICv3, or it is GICv5 with + * FEAT_GCIE_LEGACY. + */ + return kvm_vgic_global_state.type == VGIC_V3 || kvm_vgic_global_state.has_gcie_v3_compat; } -static inline bool vgic_is_v3(struct kvm *kvm) +static inline bool vgic_host_has_gicv5(void) { - return kvm_vgic_global_state.type == VGIC_V3 || vgic_is_v3_compat(kvm); + return kvm_vgic_global_state.type == VGIC_V5; } int vgic_its_debug_init(struct kvm_device *dev);
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2.34.1