KVM: arm64: vgic-debug: Don't put unmarked LPIs

If there were LPIs being mapped behind our back (i.e., between .start() and
.stop()), we would put them at iter_unmark_lpis() without checking if they
were actually *marked*, which is obviously not good.

Switch to use the xa_for_each_marked() iterator to fix it.

Cc: stable@vger.kernel.org
Fixes: 85d3ccc8 ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240817101541.1664-1-yuzenghui@huawei.comSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/kvm/vgic/vgic-debug.c

@@ -85,7 +85,7 @@ static void iter_unmark_lpis(struct kvm *kvm)
 	struct vgic_irq *irq;
 	unsigned long intid;
 
-	xa_for_each(&dist->lpi_xa, intid, irq) {
+	xa_for_each_marked(&dist->lpi_xa, intid, irq, LPI_XA_MARK_DEBUG_ITER) {
 		xa_clear_mark(&dist->lpi_xa, intid, LPI_XA_MARK_DEBUG_ITER);
 		vgic_put_irq(kvm, irq);
 	}