[PATCH v4 39/49] KVM: arm64: GICv2: Always trap GICV_DIR register

Marc Zyngier maz at kernel.org
Thu Nov 20 09:25:29 PST 2025


Since we can't decide to trap the DIR register on a per-vcpu basis,
always trap the second page of the GIC CPU interface. Yes, this is
costly. On the bright side, no sane SW should use EOImode==1 on
GICv2...

Tested-by: Fuad Tabba <tabba at google.com>
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c | 4 ++++
 arch/arm64/kvm/vgic/vgic-v2.c            | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c b/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c
index 78579b31a4205..5fd99763b54de 100644
--- a/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c
+++ b/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c
@@ -63,6 +63,10 @@ int __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu)
 		return -1;
 	}
 
+	/* Handle deactivation as a normal exit */
+	if ((fault_ipa - vgic->vgic_cpu_base) >= GIC_CPU_DEACTIVATE)
+		return 0;
+
 	rd = kvm_vcpu_dabt_get_rd(vcpu);
 	addr  = kvm_vgic_global_state.vcpu_hyp_va;
 	addr += fault_ipa - vgic->vgic_cpu_base;
diff --git a/arch/arm64/kvm/vgic/vgic-v2.c b/arch/arm64/kvm/vgic/vgic-v2.c
index bc52d44a573d5..585491fbda807 100644
--- a/arch/arm64/kvm/vgic/vgic-v2.c
+++ b/arch/arm64/kvm/vgic/vgic-v2.c
@@ -457,7 +457,7 @@ int vgic_v2_map_resources(struct kvm *kvm)
 	if (!static_branch_unlikely(&vgic_v2_cpuif_trap)) {
 		ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
 					    kvm_vgic_global_state.vcpu_base,
-					    KVM_VGIC_V2_CPU_SIZE, true);
+					    KVM_VGIC_V2_CPU_SIZE - SZ_4K, true);
 		if (ret) {
 			kvm_err("Unable to remap VGIC CPU to VCPU\n");
 			return ret;
-- 
2.47.3




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