memory: per-AddressSpace dispatch

Currently we use a global radix tree to dispatch memory access.  This only
works with a single address space; to support multiple address spaces we
make the radix tree a member of AddressSpace (via an intermediate structure
AddressSpaceDispatch to avoid exposing too many internals).

A side effect is that address_space_io also gains a dispatch table.  When
we remove all the pre-memory-API I/O registrations, we can use that for
dispatching I/O and get rid of the original I/O dispatch.

Signed-off-by: Avi Kivity <avi@redhat.com>

6 files changed, 194 insertions, 71 deletions

diff --git a/cputlb.c b/cputlb.c
index 0627f32e3..902755760 100644
--- a/cputlb.c
+++ b/cputlb.c
@@ -21,6 +21,7 @@
 #include "cpu.h"
 #include "exec-all.h"
 #include "memory.h"
+#include "exec-memory.h"
 
 #include "cputlb.h"
 
@@ -251,7 +252,7 @@ void tlb_set_page(CPUArchState *env, target_ulong vaddr,
     if (size != TARGET_PAGE_SIZE) {
         tlb_add_large_page(env, vaddr, size);
     }
-    section = phys_page_find(paddr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, paddr >> TARGET_PAGE_BITS);
 #if defined(DEBUG_TLB)
     printf("tlb_set_page: vaddr=" TARGET_FMT_lx " paddr=0x" TARGET_FMT_plx
            " prot=%x idx=%d pd=0x%08lx\n",
diff --git a/cputlb.h b/cputlb.h
index 2dc2c96cd..d537b7740 100644
--- a/cputlb.h
+++ b/cputlb.h
@@ -26,7 +26,8 @@ void tlb_unprotect_code_phys(CPUArchState *env, ram_addr_t ram_addr,
                              target_ulong vaddr);
 void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry, uintptr_t start,
                            uintptr_t length);
-MemoryRegionSection *phys_page_find(target_phys_addr_t index);
+MemoryRegionSection *phys_page_find(struct AddressSpaceDispatch *d,
+                                    target_phys_addr_t index);
 void cpu_tlb_reset_dirty_all(ram_addr_t start1, ram_addr_t length);
 void tlb_set_dirty(CPUArchState *env, target_ulong vaddr);
 extern int tlb_flush_count;
diff --git a/exec.c b/exec.c
index e732b5285..bfc4acc20 100644
--- a/exec.c
+++ b/exec.c
@@ -187,7 +187,6 @@ uintptr_t qemu_host_page_mask;
 static void *l1_map[V_L1_SIZE];
 
 #if !defined(CONFIG_USER_ONLY)
-typedef struct PhysPageEntry PhysPageEntry;
 
 static MemoryRegionSection *phys_sections;
 static unsigned phys_sections_nb, phys_sections_nb_alloc;
@@ -196,22 +195,12 @@ static uint16_t phys_section_notdirty;
 static uint16_t phys_section_rom;
 static uint16_t phys_section_watch;
 
-struct PhysPageEntry {
-    uint16_t is_leaf : 1;
-     /* index into phys_sections (is_leaf) or phys_map_nodes (!is_leaf) */
-    uint16_t ptr : 15;
-};
-
 /* Simple allocator for PhysPageEntry nodes */
 static PhysPageEntry (*phys_map_nodes)[L2_SIZE];
 static unsigned phys_map_nodes_nb, phys_map_nodes_nb_alloc;
 
 #define PHYS_MAP_NODE_NIL (((uint16_t)~0) >> 1)
 
-/* This is a multi-level map on the physical address space.
-   The bottom level has pointers to MemoryRegionSections.  */
-static PhysPageEntry phys_map = { .ptr = PHYS_MAP_NODE_NIL, .is_leaf = 0 };
-
 static void io_mem_init(void);
 static void memory_map_init(void);
 
@@ -459,18 +448,19 @@ static void phys_page_set_level(PhysPageEntry *lp, target_phys_addr_t *index,
     }
 }
 
-static void phys_page_set(target_phys_addr_t index, target_phys_addr_t nb,
+static void phys_page_set(AddressSpaceDispatch *d,
+                          target_phys_addr_t index, target_phys_addr_t nb,
                           uint16_t leaf)
 {
     /* Wildly overreserve - it doesn't matter much. */
     phys_map_node_reserve(3 * P_L2_LEVELS);
 
-    phys_page_set_level(&phys_map, &index, &nb, leaf, P_L2_LEVELS - 1);
+    phys_page_set_level(&d->phys_map, &index, &nb, leaf, P_L2_LEVELS - 1);
 }
 
-MemoryRegionSection *phys_page_find(target_phys_addr_t index)
+MemoryRegionSection *phys_page_find(AddressSpaceDispatch *d, target_phys_addr_t index)
 {
-    PhysPageEntry lp = phys_map;
+    PhysPageEntry lp = d->phys_map;
     PhysPageEntry *p;
     int i;
     uint16_t s_index = phys_section_unassigned;
@@ -1472,7 +1462,7 @@ void tb_invalidate_phys_addr(target_phys_addr_t addr)
     ram_addr_t ram_addr;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
     if (!(memory_region_is_ram(section->mr)
           || (section->mr->rom_device && section->mr->readable))) {
         return;
@@ -2210,9 +2200,9 @@ static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
     lp->ptr = PHYS_MAP_NODE_NIL;
 }
 
-static void destroy_all_mappings(void)
+static void destroy_all_mappings(AddressSpaceDispatch *d)
 {
-    destroy_l2_mapping(&phys_map, P_L2_LEVELS - 1);
+    destroy_l2_mapping(&d->phys_map, P_L2_LEVELS - 1);
     phys_map_nodes_reset();
 }
 
@@ -2232,12 +2222,12 @@ static void phys_sections_clear(void)
     phys_sections_nb = 0;
 }
 
-static void register_subpage(MemoryRegionSection *section)
+static void register_subpage(AddressSpaceDispatch *d, MemoryRegionSection *section)
 {
     subpage_t *subpage;
     target_phys_addr_t base = section->offset_within_address_space
         & TARGET_PAGE_MASK;
-    MemoryRegionSection *existing = phys_page_find(base >> TARGET_PAGE_BITS);
+    MemoryRegionSection *existing = phys_page_find(d, base >> TARGET_PAGE_BITS);
     MemoryRegionSection subsection = {
         .offset_within_address_space = base,
         .size = TARGET_PAGE_SIZE,
@@ -2249,7 +2239,7 @@ static void register_subpage(MemoryRegionSection *section)
     if (!(existing->mr->subpage)) {
         subpage = subpage_init(base);
         subsection.mr = &subpage->iomem;
-        phys_page_set(base >> TARGET_PAGE_BITS, 1,
+        phys_page_set(d, base >> TARGET_PAGE_BITS, 1,
                       phys_section_add(&subsection));
     } else {
         subpage = container_of(existing->mr, subpage_t, iomem);
@@ -2260,7 +2250,7 @@ static void register_subpage(MemoryRegionSection *section)
 }
 
 
-static void register_multipage(MemoryRegionSection *section)
+static void register_multipage(AddressSpaceDispatch *d, MemoryRegionSection *section)
 {
     target_phys_addr_t start_addr = section->offset_within_address_space;
     ram_addr_t size = section->size;
@@ -2270,13 +2260,13 @@ static void register_multipage(MemoryRegionSection *section)
     assert(size);
 
     addr = start_addr;
-    phys_page_set(addr >> TARGET_PAGE_BITS, size >> TARGET_PAGE_BITS,
+    phys_page_set(d, addr >> TARGET_PAGE_BITS, size >> TARGET_PAGE_BITS,
                   section_index);
 }
 
-void cpu_register_physical_memory_log(MemoryRegionSection *section,
-                                      bool readonly)
+static void mem_add(MemoryListener *listener, MemoryRegionSection *section)
 {
+    AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch, listener);
     MemoryRegionSection now = *section, remain = *section;
 
     if ((now.offset_within_address_space & ~TARGET_PAGE_MASK)
@@ -2284,7 +2274,7 @@ void cpu_register_physical_memory_log(MemoryRegionSection *section,
         now.size = MIN(TARGET_PAGE_ALIGN(now.offset_within_address_space)
                        - now.offset_within_address_space,
                        now.size);
-        register_subpage(&now);
+        register_subpage(d, &now);
         remain.size -= now.size;
         remain.offset_within_address_space += now.size;
         remain.offset_within_region += now.size;
@@ -2293,10 +2283,10 @@ void cpu_register_physical_memory_log(MemoryRegionSection *section,
         now = remain;
         if (remain.offset_within_region & ~TARGET_PAGE_MASK) {
             now.size = TARGET_PAGE_SIZE;
-            register_subpage(&now);
+            register_subpage(d, &now);
         } else {
             now.size &= TARGET_PAGE_MASK;
-            register_multipage(&now);
+            register_multipage(d, &now);
         }
         remain.size -= now.size;
         remain.offset_within_address_space += now.size;
@@ -2304,7 +2294,7 @@ void cpu_register_physical_memory_log(MemoryRegionSection *section,
     }
     now = remain;
     if (now.size) {
-        register_subpage(&now);
+        register_subpage(d, &now);
     }
 }
 
@@ -3155,11 +3145,17 @@ static void io_mem_init(void)
                           "watch", UINT64_MAX);
 }
 
+static void mem_begin(MemoryListener *listener)
+{
+    AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch, listener);
+
+    destroy_all_mappings(d);
+    d->phys_map.ptr = PHYS_MAP_NODE_NIL;
+}
+
 static void core_begin(MemoryListener *listener)
 {
-    destroy_all_mappings();
     phys_sections_clear();
-    phys_map.ptr = PHYS_MAP_NODE_NIL;
     phys_section_unassigned = dummy_section(&io_mem_unassigned);
     phys_section_notdirty = dummy_section(&io_mem_notdirty);
     phys_section_rom = dummy_section(&io_mem_rom);
@@ -3178,18 +3174,6 @@ static void tcg_commit(MemoryListener *listener)
     }
 }
 
-static void core_region_add(MemoryListener *listener,
-                            MemoryRegionSection *section)
-{
-    cpu_register_physical_memory_log(section, section->readonly);
-}
-
-static void core_region_nop(MemoryListener *listener,
-                            MemoryRegionSection *section)
-{
-    cpu_register_physical_memory_log(section, section->readonly);
-}
-
 static void core_log_global_start(MemoryListener *listener)
 {
     cpu_physical_memory_set_dirty_tracking(1);
@@ -3220,11 +3204,9 @@ static void io_region_del(MemoryListener *listener,
 
 static MemoryListener core_memory_listener = {
     .begin = core_begin,
-    .region_add = core_region_add,
-    .region_nop = core_region_nop,
     .log_global_start = core_log_global_start,
     .log_global_stop = core_log_global_stop,
-    .priority = 0,
+    .priority = 1,
 };
 
 static MemoryListener io_memory_listener = {
@@ -3237,6 +3219,21 @@ static MemoryListener tcg_memory_listener = {
     .commit = tcg_commit,
 };
 
+void address_space_init_dispatch(AddressSpace *as)
+{
+    AddressSpaceDispatch *d = g_new(AddressSpaceDispatch, 1);
+
+    d->phys_map  = (PhysPageEntry) { .ptr = PHYS_MAP_NODE_NIL, .is_leaf = 0 };
+    d->listener = (MemoryListener) {
+        .begin = mem_begin,
+        .region_add = mem_add,
+        .region_nop = mem_add,
+        .priority = 0,
+    };
+    as->dispatch = d;
+    memory_listener_register(&d->listener, as);
+}
+
 static void memory_map_init(void)
 {
     system_memory = g_malloc(sizeof(*system_memory));
@@ -3321,9 +3318,10 @@ static void invalidate_and_set_dirty(target_phys_addr_t addr,
     xen_modified_memory(addr, length);
 }
 
-void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
-                            int len, int is_write)
+void address_space_rw(AddressSpace *as, target_phys_addr_t addr, uint8_t *buf,
+                      int len, bool is_write)
 {
+    AddressSpaceDispatch *d = as->dispatch;
     int l;
     uint8_t *ptr;
     uint32_t val;
@@ -3335,7 +3333,7 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
-        section = phys_page_find(page >> TARGET_PAGE_BITS);
+        section = phys_page_find(d, page >> TARGET_PAGE_BITS);
 
         if (is_write) {
             if (!memory_region_is_ram(section->mr)) {
@@ -3406,10 +3404,36 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
     }
 }
 
+void address_space_write(AddressSpace *as, target_phys_addr_t addr,
+                         const uint8_t *buf, int len)
+{
+    address_space_rw(as, addr, (uint8_t *)buf, len, true);
+}
+
+/**
+ * address_space_read: read from an address space.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ */
+void address_space_read(AddressSpace *as, target_phys_addr_t addr, uint8_t *buf, int len)
+{
+    address_space_rw(as, addr, buf, len, false);
+}
+
+
+void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
+                            int len, int is_write)
+{
+    return address_space_rw(&address_space_memory, addr, buf, len, is_write);
+}
+
 /* used for ROM loading : can write in RAM and ROM */
 void cpu_physical_memory_write_rom(target_phys_addr_t addr,
                                    const uint8_t *buf, int len)
 {
+    AddressSpaceDispatch *d = address_space_memory.dispatch;
     int l;
     uint8_t *ptr;
     target_phys_addr_t page;
@@ -3420,7 +3444,7 @@ void cpu_physical_memory_write_rom(target_phys_addr_t addr,
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
-        section = phys_page_find(page >> TARGET_PAGE_BITS);
+        section = phys_page_find(d, page >> TARGET_PAGE_BITS);
 
         if (!(memory_region_is_ram(section->mr) ||
               memory_region_is_romd(section->mr))) {
@@ -3494,10 +3518,12 @@ static void cpu_notify_map_clients(void)
  * Use cpu_register_map_client() to know when retrying the map operation is
  * likely to succeed.
  */
-void *cpu_physical_memory_map(target_phys_addr_t addr,
-                              target_phys_addr_t *plen,
-                              int is_write)
+void *address_space_map(AddressSpace *as,
+                        target_phys_addr_t addr,
+                        target_phys_addr_t *plen,
+                        bool is_write)
 {
+    AddressSpaceDispatch *d = as->dispatch;
     target_phys_addr_t len = *plen;
     target_phys_addr_t todo = 0;
     int l;
@@ -3512,7 +3538,7 @@ void *cpu_physical_memory_map(target_phys_addr_t addr,
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
-        section = phys_page_find(page >> TARGET_PAGE_BITS);
+        section = phys_page_find(d, page >> TARGET_PAGE_BITS);
 
         if (!(memory_region_is_ram(section->mr) && !section->readonly)) {
             if (todo || bounce.buffer) {
@@ -3522,7 +3548,7 @@ void *cpu_physical_memory_map(target_phys_addr_t addr,
             bounce.addr = addr;
             bounce.len = l;
             if (!is_write) {
-                cpu_physical_memory_read(addr, bounce.buffer, l);
+                address_space_read(as, addr, bounce.buffer, l);
             }
 
             *plen = l;
@@ -3543,12 +3569,12 @@ void *cpu_physical_memory_map(target_phys_addr_t addr,
     return ret;
 }
 
-/* Unmaps a memory region previously mapped by cpu_physical_memory_map().
+/* Unmaps a memory region previously mapped by address_space_map().
  * Will also mark the memory as dirty if is_write == 1.  access_len gives
  * the amount of memory that was actually read or written by the caller.
  */
-void cpu_physical_memory_unmap(void *buffer, target_phys_addr_t len,
-                               int is_write, target_phys_addr_t access_len)
+void address_space_unmap(AddressSpace *as, void *buffer, target_phys_addr_t len,
+                         int is_write, target_phys_addr_t access_len)
 {
     if (buffer != bounce.buffer) {
         if (is_write) {
@@ -3569,13 +3595,26 @@ void cpu_physical_memory_unmap(void *buffer, target_phys_addr_t len,
         return;
     }
     if (is_write) {
-        cpu_physical_memory_write(bounce.addr, bounce.buffer, access_len);
+        address_space_write(as, bounce.addr, bounce.buffer, access_len);
     }
     qemu_vfree(bounce.buffer);
     bounce.buffer = NULL;
     cpu_notify_map_clients();
 }
 
+void *cpu_physical_memory_map(target_phys_addr_t addr,
+                              target_phys_addr_t *plen,
+                              int is_write)
+{
+    return address_space_map(&address_space_memory, addr, plen, is_write);
+}
+
+void cpu_physical_memory_unmap(void *buffer, target_phys_addr_t len,
+                               int is_write, target_phys_addr_t access_len)
+{
+    return address_space_unmap(&address_space_memory, buffer, len, is_write, access_len);
+}
+
 /* warning: addr must be aligned */
 static inline uint32_t ldl_phys_internal(target_phys_addr_t addr,
                                          enum device_endian endian)
@@ -3584,7 +3623,7 @@ static inline uint32_t ldl_phys_internal(target_phys_addr_t addr,
     uint32_t val;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!(memory_region_is_ram(section->mr) ||
           memory_region_is_romd(section->mr))) {
@@ -3643,7 +3682,7 @@ static inline uint64_t ldq_phys_internal(target_phys_addr_t addr,
     uint64_t val;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!(memory_region_is_ram(section->mr) ||
           memory_region_is_romd(section->mr))) {
@@ -3710,7 +3749,7 @@ static inline uint32_t lduw_phys_internal(target_phys_addr_t addr,
     uint64_t val;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!(memory_region_is_ram(section->mr) ||
           memory_region_is_romd(section->mr))) {
@@ -3769,7 +3808,7 @@ void stl_phys_notdirty(target_phys_addr_t addr, uint32_t val)
     uint8_t *ptr;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!memory_region_is_ram(section->mr) || section->readonly) {
         addr = memory_region_section_addr(section, addr);
@@ -3801,7 +3840,7 @@ void stq_phys_notdirty(target_phys_addr_t addr, uint64_t val)
     uint8_t *ptr;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!memory_region_is_ram(section->mr) || section->readonly) {
         addr = memory_region_section_addr(section, addr);
@@ -3830,7 +3869,7 @@ static inline void stl_phys_internal(target_phys_addr_t addr, uint32_t val,
     uint8_t *ptr;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!memory_region_is_ram(section->mr) || section->readonly) {
         addr = memory_region_section_addr(section, addr);
@@ -3897,7 +3936,7 @@ static inline void stw_phys_internal(target_phys_addr_t addr, uint32_t val,
     uint8_t *ptr;
     MemoryRegionSection *section;
 
-    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch, addr >> TARGET_PAGE_BITS);
 
     if (!memory_region_is_ram(section->mr) || section->readonly) {
         addr = memory_region_section_addr(section, addr);
@@ -4133,7 +4172,8 @@ bool cpu_physical_memory_is_io(target_phys_addr_t phys_addr)
 {
     MemoryRegionSection *section;
 
-    section = phys_page_find(phys_addr >> TARGET_PAGE_BITS);
+    section = phys_page_find(address_space_memory.dispatch,
+                             phys_addr >> TARGET_PAGE_BITS);
 
     return !(memory_region_is_ram(section->mr) ||
              memory_region_is_romd(section->mr));
diff --git a/memory-internal.h b/memory-internal.h
index 43fa88626..6d8711bb1 100644
--- a/memory-internal.h
+++ b/memory-internal.h
@@ -22,6 +22,26 @@
 #ifndef CONFIG_USER_ONLY
 #include "hw/xen.h"
 
+typedef struct PhysPageEntry PhysPageEntry;
+
+struct PhysPageEntry {
+    uint16_t is_leaf : 1;
+     /* index into phys_sections (is_leaf) or phys_map_nodes (!is_leaf) */
+    uint16_t ptr : 15;
+};
+
+typedef struct AddressSpaceDispatch AddressSpaceDispatch;
+
+struct AddressSpaceDispatch {
+    /* This is a multi-level map on the physical address space.
+     * The bottom level has pointers to MemoryRegionSections.
+     */
+    PhysPageEntry phys_map;
+    MemoryListener listener;
+};
+
+void address_space_init_dispatch(AddressSpace *as);
+
 ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
                                    MemoryRegion *mr);
 ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr);
@@ -30,8 +50,6 @@ void qemu_ram_free_from_ptr(ram_addr_t addr);
 
 struct MemoryRegion;
 struct MemoryRegionSection;
-void cpu_register_physical_memory_log(struct MemoryRegionSection *section,
-                                      bool readonly);
 
 void qemu_register_coalesced_mmio(target_phys_addr_t addr, ram_addr_t size);
 void qemu_unregister_coalesced_mmio(target_phys_addr_t addr, ram_addr_t size);
diff --git a/memory.c b/memory.c
index 0cf0177f4..13be84849 100644
--- a/memory.c
+++ b/memory.c
@@ -1539,6 +1539,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root)
     QTAILQ_INSERT_TAIL(&address_spaces, as, address_spaces_link);
     as->name = NULL;
     memory_region_transaction_commit();
+    address_space_init_dispatch(as);
 }
 
 uint64_t io_mem_read(MemoryRegion *mr, target_phys_addr_t addr, unsigned size)
diff --git a/memory.h b/memory.h
index f5a13a4db..d36c2baa2 100644
--- a/memory.h
+++ b/memory.h
@@ -169,6 +169,7 @@ struct AddressSpace {
     struct FlatView *current_map;
     int ioeventfd_nb;
     struct MemoryRegionIoeventfd *ioeventfds;
+    struct AddressSpaceDispatch *dispatch;
     QTAILQ_ENTRY(AddressSpace) address_spaces_link;
 };
 
@@ -803,6 +804,67 @@ void mtree_info(fprintf_function mon_printf, void *f);
  */
 void address_space_init(AddressSpace *as, MemoryRegion *root);
 
+/**
+ * address_space_rw: read from or write to an address space.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ * @is_write: indicates the transfer direction
+ */
+void address_space_rw(AddressSpace *as, target_phys_addr_t addr, uint8_t *buf,
+                      int len, bool is_write);
+
+/**
+ * address_space_write: write to address space.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ */
+void address_space_write(AddressSpace *as, target_phys_addr_t addr,
+                         const uint8_t *buf, int len);
+
+/**
+ * address_space_read: read from an address space.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ */
+void address_space_read(AddressSpace *as, target_phys_addr_t addr, uint8_t *buf, int len);
+
+/* address_space_map: map a physical memory region into a host virtual address
+ *
+ * May map a subset of the requested range, given by and returned in @plen.
+ * May return %NULL if resources needed to perform the mapping are exhausted.
+ * Use only for reads OR writes - not for read-modify-write operations.
+ * Use cpu_register_map_client() to know when retrying the map operation is
+ * likely to succeed.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @plen: pointer to length of buffer; updated on return
+ * @is_write: indicates the transfer direction
+ */
+void *address_space_map(AddressSpace *as, target_phys_addr_t addr,
+                        target_phys_addr_t *plen, bool is_write);
+
+/* address_space_unmap: Unmaps a memory region previously mapped by address_space_map()
+ *
+ * Will also mark the memory as dirty if @is_write == %true.  @access_len gives
+ * the amount of memory that was actually read or written by the caller.
+ *
+ * @as: #AddressSpace used
+ * @addr: address within that address space
+ * @len: buffer length as returned by address_space_map()
+ * @access_len: amount of data actually transferred
+ * @is_write: indicates the transfer direction
+ */
+void address_space_unmap(AddressSpace *as, void *buffer, target_phys_addr_t len,
+                         int is_write, target_phys_addr_t access_len);
+
+
 #endif
 
 #endif