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[PATCH v7 05/10] iommu/dma-reserved-iommu: reserved binding rb-tree and helpers

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we will need to track which host physical addresses are mapped to
reserved IOVA. In that prospect we introduce a new RB tree indexed
by physical address. This RB tree only is used for reserved IOVA
bindings.

It is expected this RB tree will contain very few bindings. Those
generally correspond to single page mapping one MSI frame (GICv2m
frame or ITS GITS_TRANSLATER frame).

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---
v5 -> v6:
- add comment about @d->reserved_lock to be held

v3 -> v4:
- that code was formerly in "iommu/arm-smmu: add a reserved binding RB tree"
---
 drivers/iommu/dma-reserved-iommu.c | 63 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/iommu/dma-reserved-iommu.c b/drivers/iommu/dma-reserved-iommu.c
index 2562af0..f6fa18e 100644
--- a/drivers/iommu/dma-reserved-iommu.c
+++ b/drivers/iommu/dma-reserved-iommu.c
@@ -23,6 +23,69 @@ struct reserved_iova_domain {
 	int prot; /* iommu protection attributes to be obeyed */
 };
 
+struct iommu_reserved_binding {
+	struct kref		kref;
+	struct rb_node		node;
+	struct iommu_domain	*domain;
+	phys_addr_t		addr;
+	dma_addr_t		iova;
+	size_t			size;
+};
+
+/* Reserved binding RB-tree manipulation */
+
+/* @d->reserved_lock must be held */
+static struct iommu_reserved_binding *find_reserved_binding(
+				    struct iommu_domain *d,
+				    phys_addr_t start, size_t size)
+{
+	struct rb_node *node = d->reserved_binding_list.rb_node;
+
+	while (node) {
+		struct iommu_reserved_binding *binding =
+			rb_entry(node, struct iommu_reserved_binding, node);
+
+		if (start + size <= binding->addr)
+			node = node->rb_left;
+		else if (start >= binding->addr + binding->size)
+			node = node->rb_right;
+		else
+			return binding;
+	}
+
+	return NULL;
+}
+
+/* @d->reserved_lock must be held */
+static void link_reserved_binding(struct iommu_domain *d,
+				  struct iommu_reserved_binding *new)
+{
+	struct rb_node **link = &d->reserved_binding_list.rb_node;
+	struct rb_node *parent = NULL;
+	struct iommu_reserved_binding *binding;
+
+	while (*link) {
+		parent = *link;
+		binding = rb_entry(parent, struct iommu_reserved_binding,
+				   node);
+
+		if (new->addr + new->size <= binding->addr)
+			link = &(*link)->rb_left;
+		else
+			link = &(*link)->rb_right;
+	}
+
+	rb_link_node(&new->node, parent, link);
+	rb_insert_color(&new->node, &d->reserved_binding_list);
+}
+
+/* @d->reserved_lock must be held */
+static void unlink_reserved_binding(struct iommu_domain *d,
+				    struct iommu_reserved_binding *old)
+{
+	rb_erase(&old->node, &d->reserved_binding_list);
+}
+
 int iommu_alloc_reserved_iova_domain(struct iommu_domain *domain,
 				     dma_addr_t iova, size_t size, int prot,
 				     unsigned long order)
-- 
1.9.1

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[PATCH v7 00/10] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part 1/3: iommu changes Eric Auger <eric.auger@linaro.org> - 2016-04-19 19:00 +0200
  [PATCH v7 05/10] iommu/dma-reserved-iommu: reserved binding rb-tree and helpers Eric Auger <eric.auger@linaro.org> - 2016-04-19 19:00 +0200
    Re: [PATCH v7 05/10] iommu/dma-reserved-iommu: reserved binding  rb-tree and helpers Robin Murphy <robin.murphy@arm.com> - 2016-04-20 15:20 +0200
      Re: [PATCH v7 05/10] iommu/dma-reserved-iommu: reserved binding  rb-tree and helpers Eric Auger <eric.auger@linaro.org> - 2016-04-20 18:30 +0200
        Re: [PATCH v7 05/10] iommu/dma-reserved-iommu: reserved binding  rb-tree and helpers Robin Murphy <robin.murphy@arm.com> - 2016-04-22 15:10 +0200
  [PATCH v7 10/10] iommu/arm-smmu: call iommu_free_reserved_iova_domain on domain destruction Eric Auger <eric.auger@linaro.org> - 2016-04-19 19:00 +0200
    Re: [PATCH v7 10/10] iommu/arm-smmu: call  iommu_free_reserved_iova_domain on domain destruction Robin Murphy <robin.murphy@arm.com> - 2016-04-20 19:40 +0200
      Re: [PATCH v7 10/10] iommu/arm-smmu: call  iommu_free_reserved_iova_domain on domain destruction Eric Auger <eric.auger@linaro.org> - 2016-04-21 10:50 +0200
  [PATCH v7 09/10] iommu/dma-reserved-iommu: iommu_msi_mapping_translate_msg Eric Auger <eric.auger@linaro.org> - 2016-04-19 19:00 +0200
    Re: [PATCH v7 09/10] iommu/dma-reserved-iommu:  iommu_msi_mapping_translate_msg Marc Zyngier <marc.zyngier@arm.com> - 2016-04-20 11:40 +0200
      Re: [PATCH v7 09/10] iommu/dma-reserved-iommu:  iommu_msi_mapping_translate_msg Eric Auger <eric.auger@linaro.org> - 2016-04-20 15:00 +0200
    Re: [PATCH v7 09/10] iommu/dma-reserved-iommu:  iommu_msi_mapping_translate_msg Robin Murphy <robin.murphy@arm.com> - 2016-04-20 19:30 +0200
      Re: [PATCH v7 09/10] iommu/dma-reserved-iommu:  iommu_msi_mapping_translate_msg Eric Auger <eric.auger@linaro.org> - 2016-04-21 10:50 +0200
  Re: [PATCH v7 00/10] KVM PCIe/MSI passthrough on ARM/ARM64: kernel  part 1/3: iommu changes Eric Auger <eric.auger@linaro.org> - 2016-04-21 14:20 +0200
    Re: [PATCH v7 00/10] KVM PCIe/MSI passthrough on ARM/ARM64: kernel  part 1/3: iommu changes Alex Williamson <alex.williamson@redhat.com> - 2016-04-21 21:40 +0200
      Re: [PATCH v7 00/10] KVM PCIe/MSI passthrough on ARM/ARM64: kernel  part 1/3: iommu changes Eric Auger <eric.auger@linaro.org> - 2016-04-22 14:40 +0200
        Re: [PATCH v7 00/10] KVM PCIe/MSI passthrough on ARM/ARM64: kernel  part 1/3: iommu changes Alex Williamson <alex.williamson@redhat.com> - 2016-04-22 21:10 +0200

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