KVM: arm64: vgic: Allow registration of a non-maskable maintenance interrupt

Our Apple M1/M2 friends do have a per-CPU maintenance interrupt,
but no mask to make use of it in the standard Linux framework.

Given that KVM directly drives the *source* of the interrupt and
leaves the GIC interrupt always enabled, there is no harm in tolerating
such a setup. It will become useful once we enable NV on M2 HW.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230103095022.3230946-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index f6d4f40..e61d9ca 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -572,7 +572,7 @@ int kvm_vgic_hyp_init(void)
        if (ret)
                return ret;
 
-       if (!has_mask)
+       if (!has_mask && !kvm_vgic_global_state.maint_irq)
                return 0;
 
        ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,