Hi Andre,
On 28/09/16 19:24, Andre Przywara wrote:
+/*
+ * Holding struct pending_irq's for each possible virtual LPI in each domain
+ * requires too much Xen memory, also a malicious guest could potentially
+ * spam Xen with LPI map requests. We cannot cover those with (guest allocated)
+ * ITS memory, so we use a dynamic scheme of allocating struct pending_irq's
+ * on demand.
+ */
+struct pending_irq *lpi_to_pending(struct vcpu *v, unsigned int lpi,
+ bool allocate)
+{
+ struct lpi_pending_irq *lpi_irq, *empty = NULL;
+
+ /* TODO: locking! */
+ list_for_each_entry(lpi_irq, &v->arch.vgic.pending_lpi_list, entry)
+ {
+ if ( lpi_irq->pirq.irq == lpi )
+ return &lpi_irq->pirq;
+
+ if ( lpi_irq->pirq.irq == 0 && !empty )
+ empty = lpi_irq;
+ }
+
+ if ( !allocate )
+ return NULL;
+
+ if ( !empty )
+ {
+ empty = xzalloc(struct lpi_pending_irq);
xzalloc can return NULL if we fail to allocate memory.
+ vgic_init_pending_irq(&empty->pirq, lpi);
+ list_add_tail(&empty->entry, &v->arch.vgic.pending_lpi_list);
+ } else
+ {
+ empty->pirq.status = 0;
+ empty->pirq.irq = lpi;
+ }
+
+ return &empty->pirq;
+}
+
Regards,
--
Julien Grall
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