iommu: Add IOMMU index argument to notifier APIs

Add support for multiple IOMMU indexes to the IOMMU notifier APIs.
When initializing a notifier with iommu_notifier_init(), the caller
must pass the IOMMU index that it is interested in. When a change
happens, the IOMMU implementation must pass
memory_region_notify_iommu() the IOMMU index that has changed and
that notifiers must be called for.

IOMMUs which support only a single index don't need to change.
Callers which only really support working with IOMMUs with a single
index can use the result of passing MEMTXATTRS_UNSPECIFIED to
memory_region_iommu_attrs_to_index().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20180604152941.20374-3-peter.maydell@linaro.org
diff --git a/memory.c b/memory.c
index 64f4a55..7aa75ff 100644
--- a/memory.c
+++ b/memory.c
@@ -1799,6 +1799,9 @@
     iommu_mr = IOMMU_MEMORY_REGION(mr);
     assert(n->notifier_flags != IOMMU_NOTIFIER_NONE);
     assert(n->start <= n->end);
+    assert(n->iommu_idx >= 0 &&
+           n->iommu_idx < memory_region_iommu_num_indexes(iommu_mr));
+
     QLIST_INSERT_HEAD(&iommu_mr->iommu_notify, n, node);
     memory_region_update_iommu_notify_flags(iommu_mr);
 }
@@ -1891,6 +1894,7 @@
 }
 
 void memory_region_notify_iommu(IOMMUMemoryRegion *iommu_mr,
+                                int iommu_idx,
                                 IOMMUTLBEntry entry)
 {
     IOMMUNotifier *iommu_notifier;
@@ -1898,7 +1902,9 @@
     assert(memory_region_is_iommu(MEMORY_REGION(iommu_mr)));
 
     IOMMU_NOTIFIER_FOREACH(iommu_notifier, iommu_mr) {
-        memory_region_notify_one(iommu_notifier, &entry);
+        if (iommu_notifier->iommu_idx == iommu_idx) {
+            memory_region_notify_one(iommu_notifier, &entry);
+        }
     }
 }