[PATCH v4 20/22] KVM: arm64: ITS: ITT flush and restore

[Eric Auger]

Introduce routines to flush and restore device ITT and their
interrupt table entries (ITE).

The routines will be called on device table flush and
restore. They will become static in subsequent patches.

Signed-off-by: Eric Auger <eric.auger at redhat.com>

---

v3 -> v4:
- lookup_table and compute_next_eventid_offset become static in this
  patch
- remove static along with vgic_its_flush/restore_itt to avoid
  compilation warnings
- next field only computed with a shift (mask removed)
- handle the case where the last element has not been found

v2 -> v3:
- add return 0 in vgic_its_restore_ite (was in subsequent patch)

v2: creation
---
 virt/kvm/arm/vgic/vgic-its.c | 107 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 104 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index b907e3c..02c0694 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1707,7 +1707,7 @@ u32 compute_next_devid_offset(struct list_head *h, struct its_device *dev)
 	return min_t(u32, next_offset, VITS_DTE_MAX_DEVID_OFFSET);
 }
 
-u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite)
+static u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite)
 {
 	struct list_head *e = &ite->ite_list;
 	struct its_ite *next;
@@ -1749,8 +1749,8 @@ typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *addr,
  *
  * Return: < 0 on error, 1 if last element identified, 0 otherwise
  */
-int lookup_table(struct vgic_its *its, gpa_t base, int size, int esz,
-		 int start_id, entry_fn_t fn, void *opaque)
+static int lookup_table(struct vgic_its *its, gpa_t base, int size, int esz,
+			int start_id, entry_fn_t fn, void *opaque)
 {
 	gpa_t gpa = base, top = base + size - 1;
 	unsigned long len = size;
@@ -1815,6 +1815,107 @@ static int vgic_its_restore_pending_tables(struct kvm *kvm)
 	return -ENXIO;
 }
 
+static int vgic_its_flush_ite(struct vgic_its *its, struct its_device *dev,
+			      struct its_ite *ite, gpa_t gpa)
+{
+	struct kvm *kvm = its->dev->kvm;
+	u32 next_offset;
+	u64 val;
+
+	next_offset = compute_next_eventid_offset(&dev->itt_head, ite);
+	val = ((u64)next_offset << 48) | ((u64)ite->lpi << 16) |
+		ite->collection->collection_id;
+	val = cpu_to_le64(val);
+	return kvm_write_guest(kvm, gpa, &val, VITS_ESZ);
+}
+
+/**
+ * vgic_its_restore_ite - restore an interrupt translation entry
+ * @event_id: id used for indexing
+ * @ptr: kernel VA where the 8 byte ITE is located
+ * @opaque: pointer to the its_device
+ * @next: id offset to the next entry
+ */
+static int vgic_its_restore_ite(struct vgic_its *its, u32 event_id,
+				void *ptr, void *opaque, u32 *next)
+{
+	struct its_device *dev = (struct its_device *)opaque;
+	struct its_collection *collection;
+	struct kvm *kvm = its->dev->kvm;
+	u64 val, *p = (u64 *)ptr;
+	struct vgic_irq *irq;
+	u32 coll_id, lpi_id;
+	struct its_ite *ite;
+	int ret;
+
+	val = *p;
+	*next = 1;
+
+	val = le64_to_cpu(val);
+
+	coll_id = val & GENMASK_ULL(15, 0);
+	lpi_id = (val & GENMASK_ULL(47, 16)) >> 16;
+
+	if (!lpi_id)
+		return 0;
+
+	*next = val >> 48;
+
+	collection = find_collection(its, coll_id);
+	if (!collection)
+		return -EINVAL;
+
+	ret = vgic_its_alloc_ite(dev, &ite, collection,
+				  lpi_id, event_id);
+	if (ret)
+		return ret;
+
+	irq = vgic_add_lpi(kvm, lpi_id);
+	if (IS_ERR(irq))
+		return PTR_ERR(irq);
+	ite->irq = irq;
+
+	/* restore the configuration of the LPI */
+	ret = update_lpi_config(kvm, irq, NULL);
+	if (ret)
+		return ret;
+
+	update_affinity_ite(kvm, ite);
+	return 0;
+}
+
+int vgic_its_flush_itt(struct vgic_its *its, struct its_device *device)
+{
+	gpa_t base = device->itt_addr;
+	struct its_ite *ite;
+	int ret;
+
+	list_for_each_entry(ite, &device->itt_head, ite_list) {
+		gpa_t gpa = base + ite->event_id * VITS_ESZ;
+
+		ret = vgic_its_flush_ite(its, device, ite, gpa);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
+{
+	size_t max_size = BIT_ULL(dev->nb_eventid_bits) * VITS_ESZ;
+	gpa_t base = dev->itt_addr;
+	int ret;
+
+	ret =  lookup_table(its, base, max_size, VITS_ESZ, 0,
+			    vgic_its_restore_ite, dev);
+
+	if (ret < 0)
+		return ret;
+
+	/* if the last element has not been found we are in trouble */
+	return ret ? 0 : -EINVAL;
+}
+
 /**
  * vgic_its_flush_device_tables - flush the device table and all ITT
  * into guest RAM
-- 
2.5.5