diff --git a/dma-helpers.c b/dma-helpers.c
index 6918572..33b1983 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -28,7 +28,8 @@ int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len)
     memset(fillbuf, c, FILLBUF_SIZE);
     while (len > 0) {
         l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
-        error |= address_space_rw(as, addr, fillbuf, l, true);
+        error |= address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
+                                  fillbuf, l, true);
         len -= l;
         addr += l;
     }
diff --git a/exec.c b/exec.c
index 7e53f52..29a12fa 100644
--- a/exec.c
+++ b/exec.c
@@ -1946,13 +1946,16 @@ static MemTxResult subpage_read(void *opaque, hwaddr addr, uint64_t *data,
 {
     subpage_t *subpage = opaque;
     uint8_t buf[8];
+    MemTxResult res;
 
 #if defined(DEBUG_SUBPAGE)
     printf("%s: subpage %p len %u addr " TARGET_FMT_plx "\n", __func__,
            subpage, len, addr);
 #endif
-    if (address_space_read(subpage->as, addr + subpage->base, buf, len)) {
-        return MEMTX_DECODE_ERROR;
+    res = address_space_read(subpage->as, addr + subpage->base,
+                             attrs, buf, len);
+    if (res) {
+        return res;
     }
     switch (len) {
     case 1:
@@ -1999,10 +2002,8 @@ static MemTxResult subpage_write(void *opaque, hwaddr addr,
     default:
         abort();
     }
-    if (address_space_write(subpage->as, addr + subpage->base, buf, len)) {
-        return MEMTX_DECODE_ERROR;
-    }
-    return MEMTX_OK;
+    return address_space_write(subpage->as, addr + subpage->base,
+                               attrs, buf, len);
 }
 
 static bool subpage_accepts(void *opaque, hwaddr addr,
@@ -2313,8 +2314,8 @@ static int memory_access_size(MemoryRegion *mr, unsigned l, hwaddr addr)
     return l;
 }
 
-bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
-                      int len, bool is_write)
+MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
+                             uint8_t *buf, int len, bool is_write)
 {
     hwaddr l;
     uint8_t *ptr;
@@ -2322,7 +2323,6 @@ bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
     hwaddr addr1;
     MemoryRegion *mr;
     MemTxResult result = MEMTX_OK;
-    MemTxAttrs attrs = MEMTXATTRS_UNSPECIFIED;
 
     while (len > 0) {
         l = len;
@@ -2406,22 +2406,24 @@ bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
     return result;
 }
 
-bool address_space_write(AddressSpace *as, hwaddr addr,
-                         const uint8_t *buf, int len)
+MemTxResult address_space_write(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
+                                const uint8_t *buf, int len)
 {
-    return address_space_rw(as, addr, (uint8_t *)buf, len, true);
+    return address_space_rw(as, addr, attrs, (uint8_t *)buf, len, true);
 }
 
-bool address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len)
+MemTxResult address_space_read(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
+                               uint8_t *buf, int len)
 {
-    return address_space_rw(as, addr, buf, len, false);
+    return address_space_rw(as, addr, attrs, buf, len, false);
 }
 
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
                             int len, int is_write)
 {
-    address_space_rw(&address_space_memory, addr, buf, len, is_write);
+    address_space_rw(&address_space_memory, addr, MEMTXATTRS_UNSPECIFIED,
+                     buf, len, is_write);
 }
 
 enum write_rom_type {
@@ -2592,7 +2594,8 @@ void *address_space_map(AddressSpace *as,
         memory_region_ref(mr);
         bounce.mr = mr;
         if (!is_write) {
-            address_space_read(as, addr, bounce.buffer, l);
+            address_space_read(as, addr, MEMTXATTRS_UNSPECIFIED,
+                               bounce.buffer, l);
         }
 
         *plen = l;
@@ -2645,7 +2648,8 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
         return;
     }
     if (is_write) {
-        address_space_write(as, bounce.addr, bounce.buffer, access_len);
+        address_space_write(as, bounce.addr, MEMTXATTRS_UNSPECIFIED,
+                            bounce.buffer, access_len);
     }
     qemu_vfree(bounce.buffer);
     bounce.buffer = NULL;
@@ -2787,7 +2791,7 @@ uint64_t ldq_be_phys(AddressSpace *as, hwaddr addr)
 uint32_t ldub_phys(AddressSpace *as, hwaddr addr)
 {
     uint8_t val;
-    address_space_rw(as, addr, &val, 1, 0);
+    address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, &val, 1, 0);
     return val;
 }
 
@@ -2941,7 +2945,7 @@ void stl_be_phys(AddressSpace *as, hwaddr addr, uint32_t val)
 void stb_phys(AddressSpace *as, hwaddr addr, uint32_t val)
 {
     uint8_t v = val;
-    address_space_rw(as, addr, &v, 1, 1);
+    address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, &v, 1, 1);
 }
 
 /* warning: addr must be aligned */
@@ -3004,19 +3008,19 @@ void stw_be_phys(AddressSpace *as, hwaddr addr, uint32_t val)
 void stq_phys(AddressSpace *as, hwaddr addr, uint64_t val)
 {
     val = tswap64(val);
-    address_space_rw(as, addr, (void *) &val, 8, 1);
+    address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, (void *) &val, 8, 1);
 }
 
 void stq_le_phys(AddressSpace *as, hwaddr addr, uint64_t val)
 {
     val = cpu_to_le64(val);
-    address_space_rw(as, addr, (void *) &val, 8, 1);
+    address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, (void *) &val, 8, 1);
 }
 
 void stq_be_phys(AddressSpace *as, hwaddr addr, uint64_t val)
 {
     val = cpu_to_be64(val);
-    address_space_rw(as, addr, (void *) &val, 8, 1);
+    address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, (void *) &val, 8, 1);
 }
 
 /* virtual memory access for debug (includes writing to ROM) */
@@ -3040,7 +3044,8 @@ int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
         if (is_write) {
             cpu_physical_memory_write_rom(cpu->as, phys_addr, buf, l);
         } else {
-            address_space_rw(cpu->as, phys_addr, buf, l, 0);
+            address_space_rw(cpu->as, phys_addr, MEMTXATTRS_UNSPECIFIED,
+                             buf, l, 0);
         }
         len -= l;
         buf += l;
diff --git a/hw/mips/mips_jazz.c b/hw/mips/mips_jazz.c
index 07f3c27..2c153e0 100644
--- a/hw/mips/mips_jazz.c
+++ b/hw/mips/mips_jazz.c
@@ -61,7 +61,8 @@ static void main_cpu_reset(void *opaque)
 static uint64_t rtc_read(void *opaque, hwaddr addr, unsigned size)
 {
     uint8_t val;
-    address_space_read(&address_space_memory, 0x90000071, &val, 1);
+    address_space_read(&address_space_memory, 0x90000071,
+                       MEMTXATTRS_UNSPECIFIED, &val, 1);
     return val;
 }
 
@@ -69,7 +70,8 @@ static void rtc_write(void *opaque, hwaddr addr,
                       uint64_t val, unsigned size)
 {
     uint8_t buf = val & 0xff;
-    address_space_write(&address_space_memory, 0x90000071, &buf, 1);
+    address_space_write(&address_space_memory, 0x90000071,
+                        MEMTXATTRS_UNSPECIFIED, &buf, 1);
 }
 
 static const MemoryRegionOps rtc_ops = {
diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index 6cea6ff..c63f45d 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -140,7 +140,8 @@ static uint64_t raven_io_read(void *opaque, hwaddr addr,
     uint8_t buf[4];
 
     addr = raven_io_address(s, addr);
-    address_space_read(&s->pci_io_as, addr + 0x80000000, buf, size);
+    address_space_read(&s->pci_io_as, addr + 0x80000000,
+                       MEMTXATTRS_UNSPECIFIED, buf, size);
 
     if (size == 1) {
         return buf[0];
@@ -171,7 +172,8 @@ static void raven_io_write(void *opaque, hwaddr addr,
         g_assert_not_reached();
     }
 
-    address_space_write(&s->pci_io_as, addr + 0x80000000, buf, size);
+    address_space_write(&s->pci_io_as, addr + 0x80000000,
+                        MEMTXATTRS_UNSPECIFIED, buf, size);
 }
 
 static const MemoryRegionOps raven_io_ops = {
diff --git a/include/exec/memory.h b/include/exec/memory.h
index de2849d..4d6afc8 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1089,41 +1089,50 @@ void address_space_destroy(AddressSpace *as);
 /**
  * address_space_rw: read from or write to an address space.
  *
- * Return true if the operation hit any unassigned memory or encountered an
- * IOMMU fault.
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
+ * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  * @is_write: indicates the transfer direction
  */
-bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
-                      int len, bool is_write);
+MemTxResult address_space_rw(AddressSpace *as, hwaddr addr,
+                             MemTxAttrs attrs, uint8_t *buf,
+                             int len, bool is_write);
 
 /**
  * address_space_write: write to address space.
  *
- * Return true if the operation hit any unassigned memory or encountered an
- * IOMMU fault.
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
+ * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  */
-bool address_space_write(AddressSpace *as, hwaddr addr,
-                         const uint8_t *buf, int len);
+MemTxResult address_space_write(AddressSpace *as, hwaddr addr,
+                                MemTxAttrs attrs,
+                                const uint8_t *buf, int len);
 
 /**
  * address_space_read: read from an address space.
  *
- * Return true if the operation hit any unassigned memory or encountered an
- * IOMMU fault.
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
+ * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  */
-bool address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len);
+MemTxResult address_space_read(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
+                               uint8_t *buf, int len);
 
 /* address_space_translate: translate an address range into an address space
  * into a MemoryRegion and an address range into that section
diff --git a/include/sysemu/dma.h b/include/sysemu/dma.h
index 3f2f4c8..efa8b99 100644
--- a/include/sysemu/dma.h
+++ b/include/sysemu/dma.h
@@ -88,7 +88,8 @@ static inline int dma_memory_rw_relaxed(AddressSpace *as, dma_addr_t addr,
                                         void *buf, dma_addr_t len,
                                         DMADirection dir)
 {
-    return address_space_rw(as, addr, buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
+    return (bool)address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
+                                  buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
 }
 
 static inline int dma_memory_read_relaxed(AddressSpace *as, dma_addr_t addr,
diff --git a/ioport.c b/ioport.c
index 783a3ae..b345bd9 100644
--- a/ioport.c
+++ b/ioport.c
@@ -64,7 +64,8 @@ void cpu_outb(pio_addr_t addr, uint8_t val)
 {
     LOG_IOPORT("outb: %04"FMT_pioaddr" %02"PRIx8"\n", addr, val);
     trace_cpu_out(addr, val);
-    address_space_write(&address_space_io, addr, &val, 1);
+    address_space_write(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED,
+                        &val, 1);
 }
 
 void cpu_outw(pio_addr_t addr, uint16_t val)
@@ -74,7 +75,8 @@ void cpu_outw(pio_addr_t addr, uint16_t val)
     LOG_IOPORT("outw: %04"FMT_pioaddr" %04"PRIx16"\n", addr, val);
     trace_cpu_out(addr, val);
     stw_p(buf, val);
-    address_space_write(&address_space_io, addr, buf, 2);
+    address_space_write(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED,
+                        buf, 2);
 }
 
 void cpu_outl(pio_addr_t addr, uint32_t val)
@@ -84,14 +86,16 @@ void cpu_outl(pio_addr_t addr, uint32_t val)
     LOG_IOPORT("outl: %04"FMT_pioaddr" %08"PRIx32"\n", addr, val);
     trace_cpu_out(addr, val);
     stl_p(buf, val);
-    address_space_write(&address_space_io, addr, buf, 4);
+    address_space_write(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED,
+                        buf, 4);
 }
 
 uint8_t cpu_inb(pio_addr_t addr)
 {
     uint8_t val;
 
-    address_space_read(&address_space_io, addr, &val, 1);
+    address_space_read(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED,
+                       &val, 1);
     trace_cpu_in(addr, val);
     LOG_IOPORT("inb : %04"FMT_pioaddr" %02"PRIx8"\n", addr, val);
     return val;
@@ -102,7 +106,7 @@ uint16_t cpu_inw(pio_addr_t addr)
     uint8_t buf[2];
     uint16_t val;
 
-    address_space_read(&address_space_io, addr, buf, 2);
+    address_space_read(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED, buf, 2);
     val = lduw_p(buf);
     trace_cpu_in(addr, val);
     LOG_IOPORT("inw : %04"FMT_pioaddr" %04"PRIx16"\n", addr, val);
@@ -114,7 +118,7 @@ uint32_t cpu_inl(pio_addr_t addr)
     uint8_t buf[4];
     uint32_t val;
 
-    address_space_read(&address_space_io, addr, buf, 4);
+    address_space_read(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED, buf, 4);
     val = ldl_p(buf);
     trace_cpu_in(addr, val);
     LOG_IOPORT("inl : %04"FMT_pioaddr" %08"PRIx32"\n", addr, val);
diff --git a/kvm-all.c b/kvm-all.c
index dd44f8c..4ec153d 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1667,7 +1667,8 @@ static void kvm_handle_io(uint16_t port, void *data, int direction, int size,
     uint8_t *ptr = data;
 
     for (i = 0; i < count; i++) {
-        address_space_rw(&address_space_io, port, ptr, size,
+        address_space_rw(&address_space_io, port, MEMTXATTRS_UNSPECIFIED,
+                         ptr, size,
                          direction == KVM_EXIT_IO_OUT);
         ptr += size;
     }
diff --git a/scripts/coverity-model.c b/scripts/coverity-model.c
index cdda259..224d2d1 100644
--- a/scripts/coverity-model.c
+++ b/scripts/coverity-model.c
@@ -46,6 +46,8 @@ typedef struct va_list_str *va_list;
 
 typedef struct AddressSpace AddressSpace;
 typedef uint64_t hwaddr;
+typedef uint32_t MemTxResult;
+typedef uint64_t MemTxAttrs;
 
 static void __write(uint8_t *buf, ssize_t len)
 {
@@ -65,10 +67,10 @@ static void __read(uint8_t *buf, ssize_t len)
     int last = buf[len-1];
 }
 
-bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
-                      int len, bool is_write)
+MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
+                             uint8_t *buf, int len, bool is_write)
 {
-    bool result;
+    MemTxResult result;
 
     // TODO: investigate impact of treating reads as producing
     // tainted data, with __coverity_tainted_data_argument__(buf).
