[PATCH v4 15/22] KVM: arm64: ITS: Sort the device and ITE lists

Eric Auger
2017-03-27T09:30:40Z

Natively sort the device and ITE lists in ascending
deviceId/eventid order. This paves the way to optimized
DTE and ITE scan in guest RAM table where entries are chained
together using a next ID offset.

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

---

v3 -> v4:
- added Andre's R-b
---
virt/kvm/arm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 2a1ccbf..7364b7d 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -726,6 +726,21 @@ static void vgic_its_free_collection(struct vgic_its *its, u32 coll_id)
kfree(collection);
}

+static void ite_list_insert_sorted(struct list_head *h, struct its_ite *ite)
+{
+ struct list_head *pos = h->next;
+ u32 id = ite->event_id;
+
+ while (pos != h) {
+ struct its_ite *iter =
+ list_entry(pos, struct its_ite, ite_list);
+ if (id < iter->event_id)
+ break;
+ pos = pos->next;
+ }
+ list_add_tail(&ite->ite_list, pos);
+}
+
/* Must be called with its_lock mutex held */
static int vgic_its_alloc_ite(struct its_device *device,
struct its_ite **itep,
@@ -742,7 +757,7 @@ static int vgic_its_alloc_ite(struct its_device *device,
ite->collection = collection;
ite->lpi = lpi_id;

- list_add_tail(&ite->ite_list, &device->itt_head);
+ ite_list_insert_sorted(&device->itt_head, ite);
*itep = ite;
return 0;
}
@@ -835,6 +850,22 @@ static void vgic_its_unmap_device(struct kvm *kvm, struct its_device *device)
kfree(device);
}

+static void device_list_insert_sorted(struct list_head *h,
+ struct its_device *dev)
+{
+ struct list_head *pos = h->next;
+ u32 id = dev->device_id;
+
+ while (pos != h) {
+ struct its_device *iter =
+ list_entry(pos, struct its_device, dev_list);
+ if (id < iter->device_id)
+ break;
+ pos = pos->next;
+ }
+ list_add_tail(&dev->dev_list, pos);
+}
+
/* Must be called with its_lock mutex held */
static int vgic_its_alloc_device(struct vgic_its *its,
struct its_device **devp,
@@ -852,7 +883,8 @@ static int vgic_its_alloc_device(struct vgic_its *its,
device->nb_eventid_bits = nb_eventid_bits;
INIT_LIST_HEAD(&device->itt_head);

- list_add_tail(&device->dev_list, &its->device_list);
+ device_list_insert_sorted(&its->device_list, device);
+
*devp = device;

return 0;
--
2.5.5