KVM: arm64: vgic-its: Connect LPIs to the VGIC emulation

LPIs are dynamically created (mapped) at guest runtime and their
actual number can be quite high, but is mostly assigned using a very
sparse allocation scheme. So arrays are not an ideal data structure
to hold the information.
We use a spin-lock protected linked list to hold all mapped LPIs,
represented by their struct vgic_irq. This lock is grouped between the
ap_list_lock and the vgic_irq lock in our locking order.
Also we store a pointer to that struct vgic_irq in our struct its_itte,
so we can easily access it.
Eventually we call our new vgic_get_lpi() from vgic_get_irq(), so
the VGIC code gets transparently access to LPIs.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 11cfe2f..14f91ff 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -56,6 +56,7 @@ struct its_collection {
 struct its_itte {
 	struct list_head itte_list;
 
+	struct vgic_irq *irq;
 	struct its_collection *collection;
 	u32 lpi;
 	u32 event_id;
@@ -148,6 +149,10 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
 static void its_free_itte(struct kvm *kvm, struct its_itte *itte)
 {
 	list_del(&itte->itte_list);
+
+	/* This put matches the get in vgic_add_lpi. */
+	vgic_put_irq(kvm, itte->irq);
+
 	kfree(itte);
 }