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Diffstat (limited to 'hw/i386/intel_iommu.c')
-rw-r--r--hw/i386/intel_iommu.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index b925e65b02..69d72ad35c 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -4205,9 +4205,30 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
     VTDAddressSpace *vtd_dev_as;
     char name[128];
 
+    vtd_iommu_lock(s);
     vtd_dev_as = g_hash_table_lookup(s->vtd_address_spaces, &key);
+    vtd_iommu_unlock(s);
+
     if (!vtd_dev_as) {
-        struct vtd_as_key *new_key = g_malloc(sizeof(*new_key));
+        struct vtd_as_key *new_key;
+        /* Slow path */
+
+        /*
+         * memory_region_add_subregion_overlap requires the bql,
+         * make sure we own it.
+         */
+        BQL_LOCK_GUARD();
+        vtd_iommu_lock(s);
+
+        /* Check again as we released the lock for a moment */
+        vtd_dev_as = g_hash_table_lookup(s->vtd_address_spaces, &key);
+        if (vtd_dev_as) {
+            vtd_iommu_unlock(s);
+            return vtd_dev_as;
+        }
+
+        /* Still nothing, allocate a new address space */
+        new_key = g_malloc(sizeof(*new_key));
 
         new_key->bus = bus;
         new_key->devfn = devfn;
@@ -4298,6 +4319,8 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus,
         vtd_switch_address_space(vtd_dev_as);
 
         g_hash_table_insert(s->vtd_address_spaces, new_key, vtd_dev_as);
+
+        vtd_iommu_unlock(s);
     }
     return vtd_dev_as;
 }