fuzz: Add DMA support to the generic-fuzzer

When a virtual-device tries to access some buffer in memory over DMA, we
add call-backs into the fuzzer(next commit). The fuzzer checks verifies
that the DMA request maps to a physical RAM address and fills the memory
with fuzzer-provided data. The patterns that we use to fill this memory
are specified using add_dma_pattern and clear_dma_patterns operations.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-5-alxndr@bu.edu>
[thuth: Reformatted one comment according to the QEMU coding style]
Signed-off-by: Thomas Huth <thuth@redhat.com>
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 042918d..93d27bf 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -42,6 +42,13 @@
 DECLARE_OBJ_CHECKERS(IOMMUMemoryRegion, IOMMUMemoryRegionClass,
                      IOMMU_MEMORY_REGION, TYPE_IOMMU_MEMORY_REGION)
 
+#ifdef CONFIG_FUZZ
+void fuzz_dma_read_cb(size_t addr,
+                      size_t len,
+                      MemoryRegion *mr,
+                      bool is_write);
+#endif
+
 extern bool global_dirty_log;
 
 typedef struct MemoryRegionOps MemoryRegionOps;