KVM: arm64: Set ID_{AA64PFR0,PFR1}_EL1.GIC when GICv3 is configured

Drive the idreg fields indicating the presence of GICv3 directly from
the vgic code. This avoids having to do any sort of runtime clearing
of the idreg.

Fixes: 5cb57a1aff755 ("KVM: arm64: Zero ID_AA64PFR0_EL1.GIC when no GICv3 is presented to the guest")
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20251030122707.2033690-3-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 1796b1a22a72a1f7b351f1518c76d62ef3954017..ca411cce41409d3edf52be54707b52f3f5a879a3 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -71,6 +71,7 @@ static int vgic_allocate_private_irqs_locked(struct kvm_vcpu *vcpu, u32 type);
 int kvm_vgic_create(struct kvm *kvm, u32 type)
 {
        struct kvm_vcpu *vcpu;
+       u64 aa64pfr0, pfr1;
        unsigned long i;
        int ret;
 
@@ -161,10 +162,19 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 
        kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 
-       if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
+       aa64pfr0 = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;
+       pfr1 = kvm_read_vm_id_reg(kvm, SYS_ID_PFR1_EL1) & ~ID_PFR1_EL1_GIC;
+
+       if (type == KVM_DEV_TYPE_ARM_VGIC_V2) {
                kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
-       else
+       } else {
                INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
+               aa64pfr0 |= SYS_FIELD_PREP_ENUM(ID_AA64PFR0_EL1, GIC, IMP);
+               pfr1 |= SYS_FIELD_PREP_ENUM(ID_PFR1_EL1, GIC, GICv3);
+       }
+
+       kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1, aa64pfr0);
+       kvm_set_vm_id_reg(kvm, SYS_ID_PFR1_EL1, pfr1);
 
        if (type == KVM_DEV_TYPE_ARM_VGIC_V3)
                kvm->arch.vgic.nassgicap = system_supports_direct_sgis();