If an IOMMU supports mappings that care about the memory
transaction attributes, then it no longer has a unique
address -> output mapping, but more than one. We can
represent these using an IOMMU index, analogous to TCG's
mmu indexes.
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
include/exec/memory.h | 52 +++++++++++++++++++++++++++++++++++++++++++
memory.c | 23 +++++++++++++++++++
2 files changed, 75 insertions(+)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 309fdfb89b..f6226fb263 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -206,6 +206,20 @@ enum IOMMUMemoryRegionAttr {
* to report whenever mappings are changed, by calling
* memory_region_notify_iommu() (or, if necessary, by calling
* memory_region_notify_one() for each registered notifier).
+ *
+ * Conceptually an IOMMU provides a mapping from input address
+ * to an output TLB entry. If the IOMMU is aware of memory transaction
+ * attributes and the output TLB entry depends on the transaction
+ * attributes, we represent this using IOMMU indexes. Each index
+ * selects a particular translation table that the IOMMU has:
+ * @attrs_to_index returns the IOMMU index for a set of transaction
attributes
+ * @translate takes an input address and an IOMMU index
+ * and the mapping returned can only depend on the input address and the
+ * IOMMU index.
+ *
+ * Most IOMMUs don't care about the transaction attributes and support
+ * only a single IOMMU index. A more complex IOMMU might have one index
+ * for secure transactions and one for non-secure transactions.
*/
typedef struct IOMMUMemoryRegionClass {
/* private */
@@ -290,6 +304,26 @@ typedef struct IOMMUMemoryRegionClass {
*/
int (*get_attr)(IOMMUMemoryRegion *iommu, enum IOMMUMemoryRegionAttr attr,
void *data);
+
+ /* Return the IOMMU index to use for a given set of transaction attributes.
+ *
+ * Optional method: if an IOMMU only supports a single IOMMU index then
+ * the default implementation of memory_region_iommu_attrs_to_index()
+ * will return 0.
+ *
+ * The indexes supported by an IOMMU must be contiguous, starting at 0.
+ *
+ * @iommu: the IOMMUMemoryRegion
+ * @attrs: memory transaction attributes
+ */
+ int (*attrs_to_index)(IOMMUMemoryRegion *iommu, MemTxAttrs attrs);
+
+ /* Return the number of IOMMU indexes this IOMMU supports.
+ *
+ * Optional method: if this method is not provided, then
+ * memory_region_iommu_num_indexes() will return 1, indicating that
+ * only a single IOMMU index is supported.
+ */
} IOMMUMemoryRegionClass;
typedef struct CoalescedMemoryRange CoalescedMemoryRange;
@@ -1077,6 +1111,24 @@ int memory_region_iommu_get_attr(IOMMUMemoryRegion
*iommu_mr,
enum IOMMUMemoryRegionAttr attr,
void *data);
+/**
+ * memory_region_iommu_attrs_to_index: return the IOMMU index to
+ * use for translations with the given memory transaction attributes.
+ *
+ * @iommu_mr: the memory region
+ * @attrs: the memory transaction attributes
+ */
+int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
+ MemTxAttrs attrs);
+
+/**
+ * memory_region_iommu_num_indexes: return the total number of IOMMU
+ * indexes that this IOMMU supports.
+ *
+ * @iommu_mr: the memory region
+ */
+int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr);
+
/**
* memory_region_name: get a memory region's name
*
diff --git a/memory.c b/memory.c
index 10fa2ddd31..07d5fa7862 100644
--- a/memory.c
+++ b/memory.c
@@ -1918,6 +1918,29 @@ int memory_region_iommu_get_attr(IOMMUMemoryRegion
*iommu_mr,
return imrc->get_attr(iommu_mr, attr, data);
}
+int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
+ MemTxAttrs attrs)
+{
+ IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
+
+ if (!imrc->attrs_to_index) {
+ return 0;
+ }
+
+ return imrc->attrs_to_index(iommu_mr, attrs);
+}
+
+int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr)
+{
+ IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
+
+ if (!imrc->num_indexes) {
+ return 1;
+ }
+
+ return imrc->num_indexes(iommu_mr);
+}
+
void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client)
{
uint8_t mask = 1 << client;
--
2.17.0
