memory: Introduce memory_region_iommu_set_iova_ranges

This helper will allow to convey information about valid
IOVA ranges to virtual IOMMUS.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: "Michael S. Tsirkin" <mst@redhat.com>
[ clg: fixes in memory_region_iommu_set_iova_ranges() and
       iommu_set_iova_ranges() documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>

include/exec/memory.h

@@ -527,6 +527,26 @@ struct IOMMUMemoryRegionClass {
      int (*iommu_set_page_size_mask)(IOMMUMemoryRegion *iommu,
                                      uint64_t page_size_mask,
                                      Error **errp);
+    /**
+     * @iommu_set_iova_ranges:
+     *
+     * Propagate information about the usable IOVA ranges for a given IOMMU
+     * memory region. Used for example to propagate host physical device
+     * reserved memory region constraints to the virtual IOMMU.
+     *
+     * Optional method: if this method is not provided, then the default IOVA
+     * aperture is used.
+     *
+     * @iommu: the IOMMUMemoryRegion
+     *
+     * @iova_ranges: list of ordered IOVA ranges (at least one range)
+     *
+     * Returns 0 on success, or a negative error. In case of failure, the error
+     * object must be created.
+     */
+     int (*iommu_set_iova_ranges)(IOMMUMemoryRegion *iommu,
+                                  GList *iova_ranges,
+                                  Error **errp);
 };
 
 typedef struct RamDiscardListener RamDiscardListener;
@@ -1856,6 +1876,18 @@ int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
                                            uint64_t page_size_mask,
                                            Error **errp);
 
+/**
+ * memory_region_iommu_set_iova_ranges - Set the usable IOVA ranges
+ * for a given IOMMU MR region
+ *
+ * @iommu: IOMMU memory region
+ * @iova_ranges: list of ordered IOVA ranges (at least one range)
+ * @errp: pointer to Error*, to store an error if it happens.
+ */
+int memory_region_iommu_set_iova_ranges(IOMMUMemoryRegion *iommu,
+                                        GList *iova_ranges,
+                                        Error **errp);
+
 /**
  * memory_region_name: get a memory region's name
  *

system/memory.c

@@ -1921,6 +1921,19 @@ int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
     return ret;
 }
 
+int memory_region_iommu_set_iova_ranges(IOMMUMemoryRegion *iommu_mr,
+                                        GList *iova_ranges,
+                                        Error **errp)
+{
+    IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_GET_CLASS(iommu_mr);
+    int ret = 0;
+
+    if (imrc->iommu_set_iova_ranges) {
+        ret = imrc->iommu_set_iova_ranges(iommu_mr, iova_ranges, errp);
+    }
+    return ret;
+}
+
 int memory_region_register_iommu_notifier(MemoryRegion *mr,
                                           IOMMUNotifier *n, Error **errp)
 {