diff --git a/dma.h b/dma.h
index fe08b72..4449a0c 100644
--- a/dma.h
+++ b/dma.h
@@ -34,6 +34,106 @@ typedef target_phys_addr_t dma_addr_t;
 #define DMA_ADDR_BITS TARGET_PHYS_ADDR_BITS
 #define DMA_ADDR_FMT TARGET_FMT_plx
 
+/* Checks that the given range of addresses is valid for DMA.  This is
+ * useful for certain cases, but usually you should just use
+ * dma_memory_{read,write}() and check for errors */
+static inline bool dma_memory_valid(DMAContext *dma, dma_addr_t addr,
+                                    dma_addr_t len, DMADirection dir)
+{
+    /* Stub version, with no iommu we assume all bus addresses are valid */
+    return true;
+}
+
+static inline int dma_memory_rw(DMAContext *dma, dma_addr_t addr,
+                                void *buf, dma_addr_t len, DMADirection dir)
+{
+    /* Stub version when we have no iommu support */
+    cpu_physical_memory_rw(addr, buf, (target_phys_addr_t)len,
+                           dir == DMA_DIRECTION_FROM_DEVICE);
+    return 0;
+}
+
+static inline int dma_memory_read(DMAContext *dma, dma_addr_t addr,
+                                  void *buf, dma_addr_t len)
+{
+    return dma_memory_rw(dma, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
+}
+
+static inline int dma_memory_write(DMAContext *dma, dma_addr_t addr,
+                                   const void *buf, dma_addr_t len)
+{
+    return dma_memory_rw(dma, addr, (void *)buf, len,
+                         DMA_DIRECTION_FROM_DEVICE);
+}
+
+static inline int dma_memory_set(DMAContext *dma, dma_addr_t addr,
+                                 uint8_t c, dma_addr_t len)
+{
+    /* Stub version when we have no iommu support */
+    cpu_physical_memory_set(addr, c, len);
+    return 0;
+}
+
+static inline void *dma_memory_map(DMAContext *dma,
+                                   dma_addr_t addr, dma_addr_t *len,
+                                   DMADirection dir)
+{
+    target_phys_addr_t xlen = *len;
+    void *p;
+
+    p = cpu_physical_memory_map(addr, &xlen,
+                                dir == DMA_DIRECTION_FROM_DEVICE);
+    *len = xlen;
+    return p;
+}
+
+static inline void dma_memory_unmap(DMAContext *dma,
+                                    void *buffer, dma_addr_t len,
+                                    DMADirection dir, dma_addr_t access_len)
+{
+    return cpu_physical_memory_unmap(buffer, (target_phys_addr_t)len,
+                                     dir == DMA_DIRECTION_FROM_DEVICE,
+                                     access_len);
+}
+
+#define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
+    static inline uint##_bits##_t ld##_lname##_##_end##_dma(DMAContext *dma, \
+                                                            dma_addr_t addr) \
+    {                                                                   \
+        uint##_bits##_t val;                                            \
+        dma_memory_read(dma, addr, &val, (_bits) / 8);                  \
+        return _end##_bits##_to_cpu(val);                               \
+    }                                                                   \
+    static inline void st##_sname##_##_end##_dma(DMAContext *dma,       \
+                                                 dma_addr_t addr,       \
+                                                 uint##_bits##_t val)   \
+    {                                                                   \
+        val = cpu_to_##_end##_bits(val);                                \
+        dma_memory_write(dma, addr, &val, (_bits) / 8);                 \
+    }
+
+static inline uint8_t ldub_dma(DMAContext *dma, dma_addr_t addr)
+{
+    uint8_t val;
+
+    dma_memory_read(dma, addr, &val, 1);
+    return val;
+}
+
+static inline void stb_dma(DMAContext *dma, dma_addr_t addr, uint8_t val)
+{
+    dma_memory_write(dma, addr, &val, 1);
+}
+
+DEFINE_LDST_DMA(uw, w, 16, le);
+DEFINE_LDST_DMA(l, l, 32, le);
+DEFINE_LDST_DMA(q, q, 64, le);
+DEFINE_LDST_DMA(uw, w, 16, be);
+DEFINE_LDST_DMA(l, l, 32, be);
+DEFINE_LDST_DMA(q, q, 64, be);
+
+#undef DEFINE_LDST_DMA
+
 struct ScatterGatherEntry {
     dma_addr_t base;
     dma_addr_t len;
diff --git a/hw/pci.h b/hw/pci.h
index 7f223c0..ee669d9 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -558,10 +558,16 @@ static inline uint32_t pci_config_size(const PCIDevice *d)
 }
 
 /* DMA access functions */
+static inline DMAContext *pci_dma_context(PCIDevice *dev)
+{
+    /* Stub for when we have no PCI iommu support */
+    return NULL;
+}
+
 static inline int pci_dma_rw(PCIDevice *dev, dma_addr_t addr,
                              void *buf, dma_addr_t len, DMADirection dir)
 {
-    cpu_physical_memory_rw(addr, buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
+    dma_memory_rw(pci_dma_context(dev), addr, buf, len, dir);
     return 0;
 }
 
@@ -581,12 +587,12 @@ static inline int pci_dma_write(PCIDevice *dev, dma_addr_t addr,
     static inline uint##_bits##_t ld##_l##_pci_dma(PCIDevice *dev,      \
                                                    dma_addr_t addr)     \
     {                                                                   \
-        return ld##_l##_phys(addr);                                     \
+        return ld##_l##_dma(pci_dma_context(dev), addr);                \
     }                                                                   \
     static inline void st##_s##_pci_dma(PCIDevice *dev,                 \
-                          dma_addr_t addr, uint##_bits##_t val)         \
+                                        dma_addr_t addr, uint##_bits##_t val) \
     {                                                                   \
-        st##_s##_phys(addr, val);                                       \
+        st##_s##_dma(pci_dma_context(dev), addr, val);                  \
     }
 
 PCI_DMA_DEFINE_LDST(ub, b, 8);
@@ -602,19 +608,16 @@ PCI_DMA_DEFINE_LDST(q_be, q_be, 64);
 static inline void *pci_dma_map(PCIDevice *dev, dma_addr_t addr,
                                 dma_addr_t *plen, DMADirection dir)
 {
-    target_phys_addr_t len = *plen;
     void *buf;
 
-    buf = cpu_physical_memory_map(addr, &len, dir == DMA_DIRECTION_FROM_DEVICE);
-    *plen = len;
+    buf = dma_memory_map(pci_dma_context(dev), addr, plen, dir);
     return buf;
 }
 
 static inline void pci_dma_unmap(PCIDevice *dev, void *buffer, dma_addr_t len,
                                  DMADirection dir, dma_addr_t access_len)
 {
-    cpu_physical_memory_unmap(buffer, len, dir == DMA_DIRECTION_FROM_DEVICE,
-                              access_len);
+    dma_memory_unmap(pci_dma_context(dev), buffer, len, dir, access_len);
 }
 
 static inline void pci_dma_sglist_init(QEMUSGList *qsg, PCIDevice *dev,
diff --git a/qemu-common.h b/qemu-common.h
index 8f87e41..80026af 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -264,6 +264,7 @@ typedef struct EventNotifier EventNotifier;
 typedef struct VirtIODevice VirtIODevice;
 typedef struct QEMUSGList QEMUSGList;
 typedef struct SHPCDevice SHPCDevice;
+typedef struct DMAContext DMAContext;
 
 typedef uint64_t pcibus_t;
 
