Merge remote-tracking branch 'qemu-kvm/memory/core' into staging

* qemu-kvm/memory/core: (30 commits)
  memory: allow phys_map tree paths to terminate early
  memory: unify PhysPageEntry::node and ::leaf
  memory: change phys_page_set() to set multiple pages
  memory: switch phys_page_set() to a recursive implementation
  memory: replace phys_page_find_alloc() with phys_page_set()
  memory: simplify multipage/subpage registration
  memory: give phys_page_find() its own tree search loop
  memory: make phys_page_find() return a MemoryRegionSection
  memory: move tlb flush to MemoryListener commit callback
  memory: unify the two branches of cpu_register_physical_memory_log()
  memory: fix RAM subpages in newly initialized pages
  memory: compress phys_map node pointers to 16 bits
  memory: store MemoryRegionSection pointers in phys_map
  memory: unify phys_map last level with intermediate levels
  memory: remove first level of l1_phys_map
  memory: change memory registration to rebuild the memory map on each change
  memory: support stateless memory listeners
  memory: split memory listener for the two address spaces
  xen: ignore I/O memory regions
  memory: allow MemoryListeners to observe a specific address space
  ...

9 files changed, 912 insertions, 514 deletions

diff --git a/exec-obsolete.h b/exec-obsolete.h
index 94c23d0..4dbe476 100644
--- a/exec-obsolete.h
+++ b/exec-obsolete.h
@@ -37,7 +37,7 @@ void cpu_unregister_io_memory(int table_address);
 
 struct MemoryRegionSection;
 void cpu_register_physical_memory_log(struct MemoryRegionSection *section,
-                                      bool readable, bool readonly);
+                                      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);
@@ -121,6 +121,9 @@ static inline void cpu_physical_memory_mask_dirty_range(ram_addr_t start,
 
 void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t end,
                                      int dirty_flags);
+
+extern const IORangeOps memory_region_iorange_ops;
+
 #endif
 
 #endif
diff --git a/exec.c b/exec.c
index b81677a..0c93b26 100644
--- a/exec.c
+++ b/exec.c
@@ -160,29 +160,21 @@ typedef struct PageDesc {
 #define L2_BITS 10
 #define L2_SIZE (1 << L2_BITS)
 
+#define P_L2_LEVELS \
+    (((TARGET_PHYS_ADDR_SPACE_BITS - TARGET_PAGE_BITS - 1) / L2_BITS) + 1)
+
 /* The bits remaining after N lower levels of page tables.  */
-#define P_L1_BITS_REM \
-    ((TARGET_PHYS_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % L2_BITS)
 #define V_L1_BITS_REM \
     ((L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % L2_BITS)
 
-/* Size of the L1 page table.  Avoid silly small sizes.  */
-#if P_L1_BITS_REM < 4
-#define P_L1_BITS  (P_L1_BITS_REM + L2_BITS)
-#else
-#define P_L1_BITS  P_L1_BITS_REM
-#endif
-
 #if V_L1_BITS_REM < 4
 #define V_L1_BITS  (V_L1_BITS_REM + L2_BITS)
 #else
 #define V_L1_BITS  V_L1_BITS_REM
 #endif
 
-#define P_L1_SIZE  ((target_phys_addr_t)1 << P_L1_BITS)
 #define V_L1_SIZE  ((target_ulong)1 << V_L1_BITS)
 
-#define P_L1_SHIFT (TARGET_PHYS_ADDR_SPACE_BITS - TARGET_PAGE_BITS - P_L1_BITS)
 #define V_L1_SHIFT (L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS - V_L1_BITS)
 
 unsigned long qemu_real_host_page_size;
@@ -194,15 +186,27 @@ unsigned long qemu_host_page_mask;
 static void *l1_map[V_L1_SIZE];
 
 #if !defined(CONFIG_USER_ONLY)
-typedef struct PhysPageDesc {
-    /* offset in host memory of the page + io_index in the low bits */
-    ram_addr_t phys_offset;
-    ram_addr_t region_offset;
-} PhysPageDesc;
+typedef struct PhysPageEntry PhysPageEntry;
+
+static MemoryRegionSection *phys_sections;
+static unsigned phys_sections_nb, phys_sections_nb_alloc;
+static uint16_t phys_section_unassigned;
+
+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 PhysPageDesc.  */
-static void *l1_phys_map[P_L1_SIZE];
+   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);
@@ -398,59 +402,112 @@ static inline PageDesc *page_find(tb_page_addr_t index)
 }
 
 #if !defined(CONFIG_USER_ONLY)
-static PhysPageDesc *phys_page_find_alloc(target_phys_addr_t index, int alloc)
+
+static void phys_map_node_reserve(unsigned nodes)
 {
-    PhysPageDesc *pd;
-    void **lp;
-    int i;
+    if (phys_map_nodes_nb + nodes > phys_map_nodes_nb_alloc) {
+        typedef PhysPageEntry Node[L2_SIZE];
+        phys_map_nodes_nb_alloc = MAX(phys_map_nodes_nb_alloc * 2, 16);
+        phys_map_nodes_nb_alloc = MAX(phys_map_nodes_nb_alloc,
+                                      phys_map_nodes_nb + nodes);
+        phys_map_nodes = g_renew(Node, phys_map_nodes,
+                                 phys_map_nodes_nb_alloc);
+    }
+}
 
-    /* Level 1.  Always allocated.  */
-    lp = l1_phys_map + ((index >> P_L1_SHIFT) & (P_L1_SIZE - 1));
+static uint16_t phys_map_node_alloc(void)
+{
+    unsigned i;
+    uint16_t ret;
 
-    /* Level 2..N-1.  */
-    for (i = P_L1_SHIFT / L2_BITS - 1; i > 0; i--) {
-        void **p = *lp;
-        if (p == NULL) {
-            if (!alloc) {
-                return NULL;
-            }
-            *lp = p = g_malloc0(sizeof(void *) * L2_SIZE);
-        }
-        lp = p + ((index >> (i * L2_BITS)) & (L2_SIZE - 1));
+    ret = phys_map_nodes_nb++;
+    assert(ret != PHYS_MAP_NODE_NIL);
+    assert(ret != phys_map_nodes_nb_alloc);
+    for (i = 0; i < L2_SIZE; ++i) {
+        phys_map_nodes[ret][i].is_leaf = 0;
+        phys_map_nodes[ret][i].ptr = PHYS_MAP_NODE_NIL;
     }
+    return ret;
+}
 
-    pd = *lp;
-    if (pd == NULL) {
-        int i;
-        int first_index = index & ~(L2_SIZE - 1);
+static void phys_map_nodes_reset(void)
+{
+    phys_map_nodes_nb = 0;
+}
 
-        if (!alloc) {
-            return NULL;
-        }
 
-        *lp = pd = g_malloc(sizeof(PhysPageDesc) * L2_SIZE);
+static void phys_page_set_level(PhysPageEntry *lp, target_phys_addr_t *index,
+                                target_phys_addr_t *nb, uint16_t leaf,
+                                int level)
+{
+    PhysPageEntry *p;
+    int i;
+    target_phys_addr_t step = (target_phys_addr_t)1 << (level * L2_BITS);
+
+    if (!lp->is_leaf && lp->ptr == PHYS_MAP_NODE_NIL) {
+        lp->ptr = phys_map_node_alloc();
+        p = phys_map_nodes[lp->ptr];
+        if (level == 0) {
+            for (i = 0; i < L2_SIZE; i++) {
+                p[i].is_leaf = 1;
+                p[i].ptr = phys_section_unassigned;
+            }
+        }
+    } else {
+        p = phys_map_nodes[lp->ptr];
+    }
+    lp = &p[(*index >> (level * L2_BITS)) & (L2_SIZE - 1)];
 
-        for (i = 0; i < L2_SIZE; i++) {
-            pd[i].phys_offset = io_mem_unassigned.ram_addr;
-            pd[i].region_offset = (first_index + i) << TARGET_PAGE_BITS;
+    while (*nb && lp < &p[L2_SIZE]) {
+        if ((*index & (step - 1)) == 0 && *nb >= step) {
+            lp->is_leaf = true;
+            lp->ptr = leaf;
+            *index += step;
+            *nb -= step;
+        } else {
+            phys_page_set_level(lp, index, nb, leaf, level - 1);
         }
+        ++lp;
     }
+}
 
-    return pd + (index & (L2_SIZE - 1));
+static void phys_page_set(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);
 }
 
-static inline PhysPageDesc phys_page_find(target_phys_addr_t index)
+static MemoryRegionSection phys_page_find(target_phys_addr_t index)
 {
-    PhysPageDesc *p = phys_page_find_alloc(index, 0);
+    PhysPageEntry lp = phys_map;
+    PhysPageEntry *p;
+    int i;
+    MemoryRegionSection section;
+    target_phys_addr_t delta;
+    uint16_t s_index = phys_section_unassigned;
 
-    if (p) {
-        return *p;
-    } else {
-        return (PhysPageDesc) {
-            .phys_offset = io_mem_unassigned.ram_addr,
-            .region_offset = index << TARGET_PAGE_BITS,
-        };
+    for (i = P_L2_LEVELS - 1; i >= 0 && !lp.is_leaf; i--) {
+        if (lp.ptr == PHYS_MAP_NODE_NIL) {
+            goto not_found;
+        }
+        p = phys_map_nodes[lp.ptr];
+        lp = p[(index >> (i * L2_BITS)) & (L2_SIZE - 1)];
     }
+
+    s_index = lp.ptr;
+not_found:
+    section = phys_sections[s_index];
+    index <<= TARGET_PAGE_BITS;
+    assert(section.offset_within_address_space <= index
+           && index <= section.offset_within_address_space + section.size-1);
+    delta = index - section.offset_within_address_space;
+    section.offset_within_address_space += delta;
+    section.offset_within_region += delta;
+    section.size -= delta;
+    return section;
 }
 
 static void tlb_protect_code(ram_addr_t ram_addr);
@@ -1410,14 +1467,18 @@ static void breakpoint_invalidate(CPUState *env, target_ulong pc)
 static void breakpoint_invalidate(CPUState *env, target_ulong pc)
 {
     target_phys_addr_t addr;
-    target_ulong pd;
     ram_addr_t ram_addr;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
     addr = cpu_get_phys_page_debug(env, pc);
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
-    ram_addr = (pd & TARGET_PAGE_MASK) | (pc & ~TARGET_PAGE_MASK);
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
+    if (!(memory_region_is_ram(section.mr)
+          || (section.mr->rom_device && section.mr->readable))) {
+        return;
+    }
+    ram_addr = (memory_region_get_ram_addr(section.mr)
+                + section.offset_within_region) & TARGET_PAGE_MASK;
+    ram_addr |= (pc & ~TARGET_PAGE_MASK);
     tb_invalidate_phys_page_range(ram_addr, ram_addr + 1, 0);
 }
 #endif
@@ -2095,24 +2156,21 @@ static void tlb_add_large_page(CPUState *env, target_ulong vaddr,
     env->tlb_flush_mask = mask;
 }
 
-static bool is_ram_rom(ram_addr_t pd)
+static bool is_ram_rom(MemoryRegionSection *s)
 {
-    pd &= ~TARGET_PAGE_MASK;
-    return pd == io_mem_ram.ram_addr || pd == io_mem_rom.ram_addr;
+    return memory_region_is_ram(s->mr);
 }
 
-static bool is_romd(ram_addr_t pd)
+static bool is_romd(MemoryRegionSection *s)
 {
-    MemoryRegion *mr;
+    MemoryRegion *mr = s->mr;
 
-    pd &= ~TARGET_PAGE_MASK;
-    mr = io_mem_region[pd];
     return mr->rom_device && mr->readable;
 }
 
-static bool is_ram_rom_romd(ram_addr_t pd)
+static bool is_ram_rom_romd(MemoryRegionSection *s)
 {
-    return is_ram_rom(pd) || is_romd(pd);
+    return is_ram_rom(s) || is_romd(s);
 }
 
 /* Add a new TLB entry. At most one entry for a given virtual address
@@ -2122,8 +2180,7 @@ void tlb_set_page(CPUState *env, target_ulong vaddr,
                   target_phys_addr_t paddr, int prot,
                   int mmu_idx, target_ulong size)
 {
-    PhysPageDesc p;
-    unsigned long pd;
+    MemoryRegionSection section;
     unsigned int index;
     target_ulong address;
     target_ulong code_address;
@@ -2136,8 +2193,7 @@ void tlb_set_page(CPUState *env, target_ulong vaddr,
     if (size != TARGET_PAGE_SIZE) {
         tlb_add_large_page(env, vaddr, size);
     }
-    p = phys_page_find(paddr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(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",
@@ -2145,15 +2201,21 @@ void tlb_set_page(CPUState *env, target_ulong vaddr,
 #endif
 
     address = vaddr;
-    if (!is_ram_rom_romd(pd)) {
+    if (!is_ram_rom_romd(&section)) {
         /* IO memory case (romd handled later) */
         address |= TLB_MMIO;
     }
-    addend = (unsigned long)qemu_get_ram_ptr(pd & TARGET_PAGE_MASK);
-    if (is_ram_rom(pd)) {
+    if (is_ram_rom_romd(&section)) {
+        addend = (unsigned long)(memory_region_get_ram_ptr(section.mr)
+                                 + section.offset_within_region);
+    } else {
+        addend = 0;
+    }
+    if (is_ram_rom(&section)) {
         /* Normal RAM.  */
-        iotlb = pd & TARGET_PAGE_MASK;
-        if ((pd & ~TARGET_PAGE_MASK) == io_mem_ram.ram_addr)
+        iotlb = (memory_region_get_ram_addr(section.mr)
+                 + section.offset_within_region) & TARGET_PAGE_MASK;
+        if (!section.readonly)
             iotlb |= io_mem_notdirty.ram_addr;
         else
             iotlb |= io_mem_rom.ram_addr;
@@ -2164,8 +2226,8 @@ void tlb_set_page(CPUState *env, target_ulong vaddr,
            and avoid full address decoding in every device.
            We can't use the high bits of pd for this because
            IO_MEM_ROMD uses these as a ram address.  */
-        iotlb = (pd & ~TARGET_PAGE_MASK);
-        iotlb += p.region_offset;
+        iotlb = memory_region_get_ram_addr(section.mr) & ~TARGET_PAGE_MASK;
+        iotlb += section.offset_within_region;
     }
 
     code_address = address;
@@ -2198,11 +2260,14 @@ void tlb_set_page(CPUState *env, target_ulong vaddr,
         te->addr_code = -1;
     }
     if (prot & PAGE_WRITE) {
-        if ((pd & ~TARGET_PAGE_MASK) == io_mem_rom.ram_addr || is_romd(pd)) {
+        if ((memory_region_is_ram(section.mr) && section.readonly)
+            || is_romd(&section)) {
             /* Write access calls the I/O callback.  */
             te->addr_write = address | TLB_MMIO;
-        } else if ((pd & ~TARGET_PAGE_MASK) == io_mem_ram.ram_addr &&
-                   !cpu_physical_memory_is_dirty(pd)) {
+        } else if (memory_region_is_ram(section.mr)
+                   && !cpu_physical_memory_is_dirty(
+                           section.mr->ram_addr
+                           + section.offset_within_region)) {
             te->addr_write = address | TLB_NOTDIRTY;
         } else {
             te->addr_write = address;
@@ -2491,34 +2556,66 @@ static inline void tlb_set_dirty(CPUState *env,
 typedef struct subpage_t {
     MemoryRegion iomem;
     target_phys_addr_t base;
-    ram_addr_t sub_io_index[TARGET_PAGE_SIZE];
-    ram_addr_t region_offset[TARGET_PAGE_SIZE];
+    uint16_t sub_section[TARGET_PAGE_SIZE];
 } subpage_t;
 
 static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
-                             ram_addr_t memory, ram_addr_t region_offset);
-static subpage_t *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
-                                ram_addr_t orig_memory,
-                                ram_addr_t region_offset);
-#define CHECK_SUBPAGE(addr, start_addr, start_addr2, end_addr, end_addr2, \
-                      need_subpage)                                     \
-    do {                                                                \
-        if (addr > start_addr)                                          \
-            start_addr2 = 0;                                            \
-        else {                                                          \
-            start_addr2 = start_addr & ~TARGET_PAGE_MASK;               \
-            if (start_addr2 > 0)                                        \
-                need_subpage = 1;                                       \
-        }                                                               \
-                                                                        \
-        if ((start_addr + orig_size) - addr >= TARGET_PAGE_SIZE)        \
-            end_addr2 = TARGET_PAGE_SIZE - 1;                           \
-        else {                                                          \
-            end_addr2 = (start_addr + orig_size - 1) & ~TARGET_PAGE_MASK; \
-            if (end_addr2 < TARGET_PAGE_SIZE - 1)                       \
-                need_subpage = 1;                                       \
-        }                                                               \
-    } while (0)
+                             uint16_t section);
+static subpage_t *subpage_init(target_phys_addr_t base);
+static void destroy_page_desc(uint16_t section_index)
+{
+    MemoryRegionSection *section = &phys_sections[section_index];
+    MemoryRegion *mr = section->mr;
+
+    if (mr->subpage) {
+        subpage_t *subpage = container_of(mr, subpage_t, iomem);
+        memory_region_destroy(&subpage->iomem);
+        g_free(subpage);
+    }
+}
+
+static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
+{
+    unsigned i;
+    PhysPageEntry *p;
+
+    if (lp->ptr == PHYS_MAP_NODE_NIL) {
+        return;
+    }
+
+    p = phys_map_nodes[lp->ptr];
+    for (i = 0; i < L2_SIZE; ++i) {
+        if (!p[i].is_leaf) {
+            destroy_l2_mapping(&p[i], level - 1);
+        } else {
+            destroy_page_desc(p[i].ptr);
+        }
+    }
+    lp->is_leaf = 0;
+    lp->ptr = PHYS_MAP_NODE_NIL;
+}
+
+static void destroy_all_mappings(void)
+{
+    destroy_l2_mapping(&phys_map, P_L2_LEVELS - 1);
+    phys_map_nodes_reset();
+}
+
+static uint16_t phys_section_add(MemoryRegionSection *section)
+{
+    if (phys_sections_nb == phys_sections_nb_alloc) {
+        phys_sections_nb_alloc = MAX(phys_sections_nb_alloc * 2, 16);
+        phys_sections = g_renew(MemoryRegionSection, phys_sections,
+                                phys_sections_nb_alloc);
+    }
+    phys_sections[phys_sections_nb] = *section;
+    return phys_sections_nb++;
+}
+
+static void phys_sections_clear(void)
+{
+    phys_sections_nb = 0;
+}
 
 /* register physical memory.
    For RAM, 'size' must be a multiple of the target page size.
@@ -2528,101 +2625,78 @@ static subpage_t *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
    start_addr and region_offset are rounded down to a page boundary
    before calculating this offset.  This should not be a problem unless
    the low bits of start_addr and region_offset differ.  */
-void cpu_register_physical_memory_log(MemoryRegionSection *section,
-                                      bool readable, bool readonly)
+static void register_subpage(MemoryRegionSection *section)
 {
-    target_phys_addr_t start_addr = section->offset_within_address_space;
-    ram_addr_t size = section->size;
-    ram_addr_t phys_offset = section->mr->ram_addr;
-    ram_addr_t region_offset = section->offset_within_region;
-    target_phys_addr_t addr, end_addr;
-    PhysPageDesc *p;
-    CPUState *env;
-    ram_addr_t orig_size = size;
     subpage_t *subpage;
-
-    if (memory_region_is_ram(section->mr)) {
-        phys_offset += region_offset;
-        region_offset = 0;
+    target_phys_addr_t base = section->offset_within_address_space
+        & TARGET_PAGE_MASK;
+    MemoryRegionSection existing = phys_page_find(base >> TARGET_PAGE_BITS);
+    MemoryRegionSection subsection = {
+        .offset_within_address_space = base,
+        .size = TARGET_PAGE_SIZE,
+    };
+    target_phys_addr_t start, end;
+
+    assert(existing.mr->subpage || existing.mr == &io_mem_unassigned);
+
+    if (!(existing.mr->subpage)) {
+        subpage = subpage_init(base);
+        subsection.mr = &subpage->iomem;
+        phys_page_set(base >> TARGET_PAGE_BITS, 1,
+                      phys_section_add(&subsection));
+    } else {
+        subpage = container_of(existing.mr, subpage_t, iomem);
     }
+    start = section->offset_within_address_space & ~TARGET_PAGE_MASK;
+    end = start + section->size;
+    subpage_register(subpage, start, end, phys_section_add(section));
+}
 
-    if (readonly) {
-        phys_offset |= io_mem_rom.ram_addr;
-    }
 
-    assert(size);
+static void register_multipage(MemoryRegionSection *section)
+{
+    target_phys_addr_t start_addr = section->offset_within_address_space;
+    ram_addr_t size = section->size;
+    target_phys_addr_t addr;
+    uint16_t section_index = phys_section_add(section);
 
-    if (phys_offset == io_mem_unassigned.ram_addr) {
-        region_offset = start_addr;
-    }
-    region_offset &= TARGET_PAGE_MASK;
-    size = (size + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK;
-    end_addr = start_addr + (target_phys_addr_t)size;
+    assert(size);
 
     addr = start_addr;
-    do {
-        p = phys_page_find_alloc(addr >> TARGET_PAGE_BITS, 0);
-        if (p && p->phys_offset != io_mem_unassigned.ram_addr) {
-            ram_addr_t orig_memory = p->phys_offset;
-            target_phys_addr_t start_addr2, end_addr2;
-            int need_subpage = 0;
-            MemoryRegion *mr = io_mem_region[orig_memory & ~TARGET_PAGE_MASK];
-
-            CHECK_SUBPAGE(addr, start_addr, start_addr2, end_addr, end_addr2,
-                          need_subpage);
-            if (need_subpage) {
-                if (!(mr->subpage)) {
-                    subpage = subpage_init((addr & TARGET_PAGE_MASK),
-                                           &p->phys_offset, orig_memory,
-                                           p->region_offset);
-                } else {
-                    subpage = container_of(mr, subpage_t, iomem);
-                }
-                subpage_register(subpage, start_addr2, end_addr2, phys_offset,
-                                 region_offset);
-                p->region_offset = 0;
-            } else {
-                p->phys_offset = phys_offset;
-                p->region_offset = region_offset;
-                if (is_ram_rom_romd(phys_offset))
-                    phys_offset += TARGET_PAGE_SIZE;
-            }
-        } else {
-            p = phys_page_find_alloc(addr >> TARGET_PAGE_BITS, 1);
-            p->phys_offset = phys_offset;
-            p->region_offset = region_offset;
-            if (is_ram_rom_romd(phys_offset)) {
-                phys_offset += TARGET_PAGE_SIZE;
-            } else {
-                target_phys_addr_t start_addr2, end_addr2;
-                int need_subpage = 0;
-
-                CHECK_SUBPAGE(addr, start_addr, start_addr2, end_addr,
-                              end_addr2, need_subpage);
-
-                if (need_subpage) {
-                    subpage = subpage_init((addr & TARGET_PAGE_MASK),
-                                           &p->phys_offset,
-                                           io_mem_unassigned.ram_addr,
-                                           addr & TARGET_PAGE_MASK);
-                    subpage_register(subpage, start_addr2, end_addr2,
-                                     phys_offset, region_offset);
-                    p->region_offset = 0;
-                }
-            }
-        }
-        region_offset += TARGET_PAGE_SIZE;
-        addr += TARGET_PAGE_SIZE;
-    } while (addr != end_addr);
+    phys_page_set(addr >> TARGET_PAGE_BITS, size >> TARGET_PAGE_BITS,
+                  section_index);
+}
 
-    /* since each CPU stores ram addresses in its TLB cache, we must
-       reset the modified entries */
-    /* XXX: slow ! */
-    for(env = first_cpu; env != NULL; env = env->next_cpu) {
-        tlb_flush(env, 1);
+void cpu_register_physical_memory_log(MemoryRegionSection *section,
+                                      bool readonly)
+{
+    MemoryRegionSection now = *section, remain = *section;
+
+    if ((now.offset_within_address_space & ~TARGET_PAGE_MASK)
+        || (now.size < TARGET_PAGE_SIZE)) {
+        now.size = MIN(TARGET_PAGE_ALIGN(now.offset_within_address_space)
+                       - now.offset_within_address_space,
+                       now.size);
+        register_subpage(&now);
+        remain.size -= now.size;
+        remain.offset_within_address_space += now.size;
+        remain.offset_within_region += now.size;
+    }
+    now = remain;
+    now.size &= TARGET_PAGE_MASK;
+    if (now.size) {
+        register_multipage(&now);
+        remain.size -= now.size;
+        remain.offset_within_address_space += now.size;
+        remain.offset_within_region += now.size;
+    }
+    now = remain;
+    if (now.size) {
+        register_subpage(&now);
     }
 }
 
+
 void qemu_register_coalesced_mmio(target_phys_addr_t addr, ram_addr_t size)
 {
     if (kvm_enabled())
@@ -3307,14 +3381,17 @@ static uint64_t subpage_read(void *opaque, target_phys_addr_t addr,
 {
     subpage_t *mmio = opaque;
     unsigned int idx = SUBPAGE_IDX(addr);
+    MemoryRegionSection *section;
 #if defined(DEBUG_SUBPAGE)
     printf("%s: subpage %p len %d addr " TARGET_FMT_plx " idx %d\n", __func__,
            mmio, len, addr, idx);
 #endif
 
-    addr += mmio->region_offset[idx];
-    idx = mmio->sub_io_index[idx];
-    return io_mem_read(idx, addr, len);
+    section = &phys_sections[mmio->sub_section[idx]];
+    addr += mmio->base;
+    addr -= section->offset_within_address_space;
+    addr += section->offset_within_region;
+    return io_mem_read(section->mr->ram_addr, addr, len);
 }
 
 static void subpage_write(void *opaque, target_phys_addr_t addr,
@@ -3322,15 +3399,18 @@ static void subpage_write(void *opaque, target_phys_addr_t addr,
 {
     subpage_t *mmio = opaque;
     unsigned int idx = SUBPAGE_IDX(addr);
+    MemoryRegionSection *section;
 #if defined(DEBUG_SUBPAGE)
     printf("%s: subpage %p len %d addr " TARGET_FMT_plx
            " idx %d value %"PRIx64"\n",
            __func__, mmio, len, addr, idx, value);
 #endif
 
-    addr += mmio->region_offset[idx];
-    idx = mmio->sub_io_index[idx];
-    io_mem_write(idx, addr, value, len);
+    section = &phys_sections[mmio->sub_section[idx]];
+    addr += mmio->base;
+    addr -= section->offset_within_address_space;
+    addr += section->offset_within_region;
+    io_mem_write(section->mr->ram_addr, addr, value, len);
 }
 
 static const MemoryRegionOps subpage_ops = {
@@ -3372,7 +3452,7 @@ static const MemoryRegionOps subpage_ram_ops = {
 };
 
 static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
-                             ram_addr_t memory, ram_addr_t region_offset)
+                             uint16_t section)
 {
     int idx, eidx;
 
@@ -3384,24 +3464,21 @@ static int subpage_register (subpage_t *mmio, uint32_t start, uint32_t end,
     printf("%s: %p start %08x end %08x idx %08x eidx %08x mem %ld\n", __func__,
            mmio, start, end, idx, eidx, memory);
 #endif
-    if ((memory & ~TARGET_PAGE_MASK) == io_mem_ram.ram_addr) {
-        memory = io_mem_subpage_ram.ram_addr;
+    if (memory_region_is_ram(phys_sections[section].mr)) {
+        MemoryRegionSection new_section = phys_sections[section];
+        new_section.mr = &io_mem_subpage_ram;
+        section = phys_section_add(&new_section);
     }
-    memory &= IO_MEM_NB_ENTRIES - 1;
     for (; idx <= eidx; idx++) {
-        mmio->sub_io_index[idx] = memory;
-        mmio->region_offset[idx] = region_offset;
+        mmio->sub_section[idx] = section;
     }
 
     return 0;
 }
 
-static subpage_t *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
-                                ram_addr_t orig_memory,
-                                ram_addr_t region_offset)
+static subpage_t *subpage_init(target_phys_addr_t base)
 {
     subpage_t *mmio;
-    int subpage_memory;
 
     mmio = g_malloc0(sizeof(subpage_t));
 
@@ -3409,13 +3486,11 @@ static subpage_t *subpage_init (target_phys_addr_t base, ram_addr_t *phys,
     memory_region_init_io(&mmio->iomem, &subpage_ops, mmio,
                           "subpage", TARGET_PAGE_SIZE);
     mmio->iomem.subpage = true;
-    subpage_memory = mmio->iomem.ram_addr;
 #if defined(DEBUG_SUBPAGE)
     printf("%s: %p base " TARGET_FMT_plx " len %08x %d\n", __func__,
            mmio, base, TARGET_PAGE_SIZE, subpage_memory);
 #endif
-    *phys = subpage_memory;
-    subpage_register(mmio, 0, TARGET_PAGE_SIZE-1, orig_memory, region_offset);
+    subpage_register(mmio, 0, TARGET_PAGE_SIZE-1, phys_section_unassigned);
 
     return mmio;
 }
@@ -3467,6 +3542,18 @@ void cpu_unregister_io_memory(int io_index)
     io_mem_used[io_index] = 0;
 }
 
+static uint16_t dummy_section(MemoryRegion *mr)
+{
+    MemoryRegionSection section = {
+        .mr = mr,
+        .offset_within_address_space = 0,
+        .offset_within_region = 0,
+        .size = UINT64_MAX,
+    };
+
+    return phys_section_add(&section);
+}
+
 static void io_mem_init(void)
 {
     int i;
@@ -3488,6 +3575,174 @@ static void io_mem_init(void)
                           "watch", UINT64_MAX);
 }
 
+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);
+}
+
+static void core_commit(MemoryListener *listener)
+{
+    CPUState *env;
+
+    /* since each CPU stores ram addresses in its TLB cache, we must
+       reset the modified entries */
+    /* XXX: slow ! */
+    for(env = first_cpu; env != NULL; env = env->next_cpu) {
+        tlb_flush(env, 1);
+    }
+}
+
+static void core_region_add(MemoryListener *listener,
+                            MemoryRegionSection *section)
+{
+    cpu_register_physical_memory_log(section, section->readonly);
+}
+
+static void core_region_del(MemoryListener *listener,
+                            MemoryRegionSection *section)
+{
+}
+
+static void core_region_nop(MemoryListener *listener,
+                            MemoryRegionSection *section)
+{
+    cpu_register_physical_memory_log(section, section->readonly);
+}
+
+static void core_log_start(MemoryListener *listener,
+                           MemoryRegionSection *section)
+{
+}
+
+static void core_log_stop(MemoryListener *listener,
+                          MemoryRegionSection *section)
+{
+}
+
+static void core_log_sync(MemoryListener *listener,
+                          MemoryRegionSection *section)
+{
+}
+
+static void core_log_global_start(MemoryListener *listener)
+{
+    cpu_physical_memory_set_dirty_tracking(1);
+}
+
+static void core_log_global_stop(MemoryListener *listener)
+{
+    cpu_physical_memory_set_dirty_tracking(0);
+}
+
+static void core_eventfd_add(MemoryListener *listener,
+                             MemoryRegionSection *section,
+                             bool match_data, uint64_t data, int fd)
+{
+}
+
+static void core_eventfd_del(MemoryListener *listener,
+                             MemoryRegionSection *section,
+                             bool match_data, uint64_t data, int fd)
+{
+}
+
+static void io_begin(MemoryListener *listener)
+{
+}
+
+static void io_commit(MemoryListener *listener)
+{
+}
+
+static void io_region_add(MemoryListener *listener,
+                          MemoryRegionSection *section)
+{
+    iorange_init(&section->mr->iorange, &memory_region_iorange_ops,
+                 section->offset_within_address_space, section->size);
+    ioport_register(&section->mr->iorange);
+}
+
+static void io_region_del(MemoryListener *listener,
+                          MemoryRegionSection *section)
+{
+    isa_unassign_ioport(section->offset_within_address_space, section->size);
+}
+
+static void io_region_nop(MemoryListener *listener,
+                          MemoryRegionSection *section)
+{
+}
+
+static void io_log_start(MemoryListener *listener,
+                         MemoryRegionSection *section)
+{
+}
+
+static void io_log_stop(MemoryListener *listener,
+                        MemoryRegionSection *section)
+{
+}
+
+static void io_log_sync(MemoryListener *listener,
+                        MemoryRegionSection *section)
+{
+}
+
+static void io_log_global_start(MemoryListener *listener)
+{
+}
+
+static void io_log_global_stop(MemoryListener *listener)
+{
+}
+
+static void io_eventfd_add(MemoryListener *listener,
+                           MemoryRegionSection *section,
+                           bool match_data, uint64_t data, int fd)
+{
+}
+
+static void io_eventfd_del(MemoryListener *listener,
+                           MemoryRegionSection *section,
+                           bool match_data, uint64_t data, int fd)
+{
+}
+
+static MemoryListener core_memory_listener = {
+    .begin = core_begin,
+    .commit = core_commit,
+    .region_add = core_region_add,
+    .region_del = core_region_del,
+    .region_nop = core_region_nop,
+    .log_start = core_log_start,
+    .log_stop = core_log_stop,
+    .log_sync = core_log_sync,
+    .log_global_start = core_log_global_start,
+    .log_global_stop = core_log_global_stop,
+    .eventfd_add = core_eventfd_add,
+    .eventfd_del = core_eventfd_del,
+    .priority = 0,
+};
+
+static MemoryListener io_memory_listener = {
+    .begin = io_begin,
+    .commit = io_commit,
+    .region_add = io_region_add,
+    .region_del = io_region_del,
+    .region_nop = io_region_nop,
+    .log_start = io_log_start,
+    .log_stop = io_log_stop,
+    .log_sync = io_log_sync,
+    .log_global_start = io_log_global_start,
+    .log_global_stop = io_log_global_stop,
+    .eventfd_add = io_eventfd_add,
+    .eventfd_del = io_eventfd_del,
+    .priority = 0,
+};
+
 static void memory_map_init(void)
 {
     system_memory = g_malloc(sizeof(*system_memory));
@@ -3497,6 +3752,9 @@ static void memory_map_init(void)
     system_io = g_malloc(sizeof(*system_io));
     memory_region_init(system_io, "io", 65536);
     set_system_io_map(system_io);
+
+    memory_listener_register(&core_memory_listener, system_memory);
+    memory_listener_register(&io_memory_listener, system_io);
 }
 
 MemoryRegion *get_system_memory(void)
@@ -3560,22 +3818,22 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
     uint8_t *ptr;
     uint32_t val;
     target_phys_addr_t page;
-    ram_addr_t pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
     while (len > 0) {
         page = addr & TARGET_PAGE_MASK;
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
-        p = phys_page_find(page >> TARGET_PAGE_BITS);
-        pd = p.phys_offset;
+        section = phys_page_find(page >> TARGET_PAGE_BITS);
 
         if (is_write) {
-            if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
+            if (!memory_region_is_ram(section.mr)) {
                 target_phys_addr_t addr1;
-                io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-                addr1 = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+                io_index = memory_region_get_ram_addr(section.mr)
+                    & (IO_MEM_NB_ENTRIES - 1);
+                addr1 = (addr & ~TARGET_PAGE_MASK)
+                    + section.offset_within_region;
                 /* XXX: could force cpu_single_env to NULL to avoid
                    potential bugs */
                 if (l >= 4 && ((addr1 & 3) == 0)) {
@@ -3594,9 +3852,11 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
                     io_mem_write(io_index, addr1, val, 1);
                     l = 1;
                 }
-            } else {
+            } else if (!section.readonly) {
                 ram_addr_t addr1;
-                addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+                addr1 = (memory_region_get_ram_addr(section.mr)
+                         + section.offset_within_region)
+                    | (addr & ~TARGET_PAGE_MASK);
                 /* RAM case */
                 ptr = qemu_get_ram_ptr(addr1);
                 memcpy(ptr, buf, l);
@@ -3610,11 +3870,13 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
                 qemu_put_ram_ptr(ptr);
             }
         } else {
-            if (!is_ram_rom_romd(pd)) {
+            if (!is_ram_rom_romd(&section)) {
                 target_phys_addr_t addr1;
                 /* I/O case */
-                io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-                addr1 = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+                io_index = memory_region_get_ram_addr(section.mr)
+                    & (IO_MEM_NB_ENTRIES - 1);
+                addr1 = (addr & ~TARGET_PAGE_MASK)
+                    + section.offset_within_region;
                 if (l >= 4 && ((addr1 & 3) == 0)) {
                     /* 32 bit read access */
                     val = io_mem_read(io_index, addr1, 4);
@@ -3633,7 +3895,8 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, uint8_t *buf,
                 }
             } else {
                 /* RAM case */
-                ptr = qemu_get_ram_ptr(pd & TARGET_PAGE_MASK);
+                ptr = qemu_get_ram_ptr(section.mr->ram_addr
+                                       + section.offset_within_region);
                 memcpy(buf, ptr + (addr & ~TARGET_PAGE_MASK), l);
                 qemu_put_ram_ptr(ptr);
             }
@@ -3651,22 +3914,22 @@ void cpu_physical_memory_write_rom(target_phys_addr_t addr,
     int l;
     uint8_t *ptr;
     target_phys_addr_t page;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
     while (len > 0) {
         page = addr & TARGET_PAGE_MASK;
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
-        p = phys_page_find(page >> TARGET_PAGE_BITS);
-        pd = p.phys_offset;
+        section = phys_page_find(page >> TARGET_PAGE_BITS);
 
-        if (!is_ram_rom_romd(pd)) {
+        if (!is_ram_rom_romd(&section)) {
             /* do nothing */
         } else {
             unsigned long addr1;
-            addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+            addr1 = (memory_region_get_ram_addr(section.mr)
+                     + section.offset_within_region)
+                + (addr & ~TARGET_PAGE_MASK);
             /* ROM/RAM case */
             ptr = qemu_get_ram_ptr(addr1);
             memcpy(ptr, buf, l);
@@ -3739,8 +4002,7 @@ void *cpu_physical_memory_map(target_phys_addr_t addr,
     target_phys_addr_t todo = 0;
     int l;
     target_phys_addr_t page;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
     ram_addr_t raddr = RAM_ADDR_MAX;
     ram_addr_t rlen;
     void *ret;
@@ -3750,10 +4012,9 @@ void *cpu_physical_memory_map(target_phys_addr_t addr,
         l = (page + TARGET_PAGE_SIZE) - addr;
         if (l > len)
             l = len;
-        p = phys_page_find(page >> TARGET_PAGE_BITS);
-        pd = p.phys_offset;
+        section = phys_page_find(page >> TARGET_PAGE_BITS);
 
-        if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
+        if (!(memory_region_is_ram(section.mr) && !section.readonly)) {
             if (todo || bounce.buffer) {
                 break;
             }
@@ -3768,7 +4029,9 @@ void *cpu_physical_memory_map(target_phys_addr_t addr,
             return bounce.buffer;
         }
         if (!todo) {
-            raddr = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+            raddr = memory_region_get_ram_addr(section.mr)
+                + section.offset_within_region
+                + (addr & ~TARGET_PAGE_MASK);
         }
 
         len -= l;
@@ -3827,16 +4090,15 @@ static inline uint32_t ldl_phys_internal(target_phys_addr_t addr,
     int io_index;
     uint8_t *ptr;
     uint32_t val;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if (!is_ram_rom_romd(pd)) {
+    if (!is_ram_rom_romd(&section)) {
         /* I/O case */
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+        io_index = memory_region_get_ram_addr(section.mr)
+            & (IO_MEM_NB_ENTRIES - 1);
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
         val = io_mem_read(io_index, addr, 4);
 #if defined(TARGET_WORDS_BIGENDIAN)
         if (endian == DEVICE_LITTLE_ENDIAN) {
@@ -3849,7 +4111,9 @@ static inline uint32_t ldl_phys_internal(target_phys_addr_t addr,
 #endif
     } else {
         /* RAM case */
-        ptr = qemu_get_ram_ptr(pd & TARGET_PAGE_MASK) +
+        ptr = qemu_get_ram_ptr((memory_region_get_ram_addr(section.mr)
+                                & TARGET_PAGE_MASK)
+                               + section.offset_within_region) +
             (addr & ~TARGET_PAGE_MASK);
         switch (endian) {
         case DEVICE_LITTLE_ENDIAN:
@@ -3888,16 +4152,15 @@ static inline uint64_t ldq_phys_internal(target_phys_addr_t addr,
     int io_index;
     uint8_t *ptr;
     uint64_t val;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if (!is_ram_rom_romd(pd)) {
+    if (!is_ram_rom_romd(&section)) {
         /* I/O case */
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+        io_index = memory_region_get_ram_addr(section.mr)
+            & (IO_MEM_NB_ENTRIES - 1);
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
 
         /* XXX This is broken when device endian != cpu endian.
                Fix and add "endian" variable check */
@@ -3910,8 +4173,10 @@ static inline uint64_t ldq_phys_internal(target_phys_addr_t addr,
 #endif
     } else {
         /* RAM case */
-        ptr = qemu_get_ram_ptr(pd & TARGET_PAGE_MASK) +
-            (addr & ~TARGET_PAGE_MASK);
+        ptr = qemu_get_ram_ptr((memory_region_get_ram_addr(section.mr)
+                                & TARGET_PAGE_MASK)
+                               + section.offset_within_region)
+            + (addr & ~TARGET_PAGE_MASK);
         switch (endian) {
         case DEVICE_LITTLE_ENDIAN:
             val = ldq_le_p(ptr);
@@ -3957,16 +4222,15 @@ static inline uint32_t lduw_phys_internal(target_phys_addr_t addr,
     int io_index;
     uint8_t *ptr;
     uint64_t val;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if (!is_ram_rom_romd(pd)) {
+    if (!is_ram_rom_romd(&section)) {
         /* I/O case */
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+        io_index = memory_region_get_ram_addr(section.mr)
+            & (IO_MEM_NB_ENTRIES - 1);
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
         val = io_mem_read(io_index, addr, 2);
 #if defined(TARGET_WORDS_BIGENDIAN)
         if (endian == DEVICE_LITTLE_ENDIAN) {
@@ -3979,8 +4243,10 @@ static inline uint32_t lduw_phys_internal(target_phys_addr_t addr,
 #endif
     } else {
         /* RAM case */
-        ptr = qemu_get_ram_ptr(pd & TARGET_PAGE_MASK) +
-            (addr & ~TARGET_PAGE_MASK);
+        ptr = qemu_get_ram_ptr((memory_region_get_ram_addr(section.mr)
+                                & TARGET_PAGE_MASK)
+                               + section.offset_within_region)
+            + (addr & ~TARGET_PAGE_MASK);
         switch (endian) {
         case DEVICE_LITTLE_ENDIAN:
             val = lduw_le_p(ptr);
@@ -4018,18 +4284,23 @@ void stl_phys_notdirty(target_phys_addr_t addr, uint32_t val)
 {
     int io_index;
     uint8_t *ptr;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+    if (!memory_region_is_ram(section.mr) || section.readonly) {
+        if (memory_region_is_ram(section.mr)) {
+            io_index = io_mem_rom.ram_addr;
+        } else {
+            io_index = memory_region_get_ram_addr(section.mr);
+        }
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
         io_mem_write(io_index, addr, val, 4);
     } else {
-        unsigned long addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+        unsigned long addr1 = (memory_region_get_ram_addr(section.mr)
+                               & TARGET_PAGE_MASK)
+            + section.offset_within_region
+            + (addr & ~TARGET_PAGE_MASK);
         ptr = qemu_get_ram_ptr(addr1);
         stl_p(ptr, val);
 
@@ -4049,15 +4320,18 @@ void stq_phys_notdirty(target_phys_addr_t addr, uint64_t val)
 {
     int io_index;
     uint8_t *ptr;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+    if (!memory_region_is_ram(section.mr) || section.readonly) {
+        if (memory_region_is_ram(section.mr)) {
+                io_index = io_mem_rom.ram_addr;
+        } else {
+            io_index = memory_region_get_ram_addr(section.mr)
+                & (IO_MEM_NB_ENTRIES - 1);
+        }
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
 #ifdef TARGET_WORDS_BIGENDIAN
         io_mem_write(io_index, addr, val >> 32, 4);
         io_mem_write(io_index, addr + 4, (uint32_t)val, 4);
@@ -4066,8 +4340,10 @@ void stq_phys_notdirty(target_phys_addr_t addr, uint64_t val)
         io_mem_write(io_index, addr + 4, val >> 32, 4);
 #endif
     } else {
-        ptr = qemu_get_ram_ptr(pd & TARGET_PAGE_MASK) +
-            (addr & ~TARGET_PAGE_MASK);
+        ptr = qemu_get_ram_ptr((memory_region_get_ram_addr(section.mr)
+                                & TARGET_PAGE_MASK)
+                               + section.offset_within_region)
+            + (addr & ~TARGET_PAGE_MASK);
         stq_p(ptr, val);
     }
 }
@@ -4078,15 +4354,18 @@ static inline void stl_phys_internal(target_phys_addr_t addr, uint32_t val,
 {
     int io_index;
     uint8_t *ptr;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+    if (!memory_region_is_ram(section.mr) || section.readonly) {
+        if (memory_region_is_ram(section.mr)) {
+            io_index = io_mem_rom.ram_addr;
+        } else {
+            io_index = memory_region_get_ram_addr(section.mr)
+                & (IO_MEM_NB_ENTRIES - 1);
+        }
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
 #if defined(TARGET_WORDS_BIGENDIAN)
         if (endian == DEVICE_LITTLE_ENDIAN) {
             val = bswap32(val);
@@ -4099,7 +4378,9 @@ static inline void stl_phys_internal(target_phys_addr_t addr, uint32_t val,
         io_mem_write(io_index, addr, val, 4);
     } else {
         unsigned long addr1;
-        addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+        addr1 = (memory_region_get_ram_addr(section.mr) & TARGET_PAGE_MASK)
+            + section.offset_within_region
+            + (addr & ~TARGET_PAGE_MASK);
         /* RAM case */
         ptr = qemu_get_ram_ptr(addr1);
         switch (endian) {
@@ -4151,15 +4432,18 @@ static inline void stw_phys_internal(target_phys_addr_t addr, uint32_t val,
 {
     int io_index;
     uint8_t *ptr;
-    unsigned long pd;
-    PhysPageDesc p;
+    MemoryRegionSection section;
 
-    p = phys_page_find(addr >> TARGET_PAGE_BITS);
-    pd = p.phys_offset;
+    section = phys_page_find(addr >> TARGET_PAGE_BITS);
 
-    if ((pd & ~TARGET_PAGE_MASK) != io_mem_ram.ram_addr) {
-        io_index = pd & (IO_MEM_NB_ENTRIES - 1);
-        addr = (addr & ~TARGET_PAGE_MASK) + p.region_offset;
+    if (!memory_region_is_ram(section.mr) || section.readonly) {
+        if (memory_region_is_ram(section.mr)) {
+            io_index = io_mem_rom.ram_addr;
+        } else {
+            io_index = memory_region_get_ram_addr(section.mr)
+                & (IO_MEM_NB_ENTRIES - 1);
+        }
+        addr = (addr & ~TARGET_PAGE_MASK) + section.offset_within_region;
 #if defined(TARGET_WORDS_BIGENDIAN)
         if (endian == DEVICE_LITTLE_ENDIAN) {
             val = bswap16(val);
@@ -4172,7 +4456,8 @@ static inline void stw_phys_internal(target_phys_addr_t addr, uint32_t val,
         io_mem_write(io_index, addr, val, 2);
     } else {
         unsigned long addr1;
-        addr1 = (pd & TARGET_PAGE_MASK) + (addr & ~TARGET_PAGE_MASK);
+        addr1 = (memory_region_get_ram_addr(section.mr) & TARGET_PAGE_MASK)
+            + section.offset_within_region + (addr & ~TARGET_PAGE_MASK);
         /* RAM case */
         ptr = qemu_get_ram_ptr(addr1);
         switch (endian) {
@@ -4389,7 +4674,7 @@ tb_page_addr_t get_page_addr_code(CPUState *env1, target_ulong addr)
     }
     pd = env1->tlb_table[mmu_idx][page_index].addr_code & ~TARGET_PAGE_MASK;
     if (pd != io_mem_ram.ram_addr && pd != io_mem_rom.ram_addr
-        && !is_romd(pd)) {
+        && !io_mem_region[pd]->rom_device) {
 #if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_SPARC)
         cpu_unassigned_access(env1, addr, 0, 1, 0, 4);
 #else
diff --git a/hw/vhost.c b/hw/vhost.c
index 5ece659..8d3ba5b 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -436,6 +436,14 @@ static bool vhost_section(MemoryRegionSection *section)
         && memory_region_is_ram(section->mr);
 }
 
+static void vhost_begin(MemoryListener *listener)
+{
+}
+
+static void vhost_commit(MemoryListener *listener)
+{
+}
+
 static void vhost_region_add(MemoryListener *listener,
                              MemoryRegionSection *section)
 {
@@ -476,6 +484,11 @@ static void vhost_region_del(MemoryListener *listener,
     }
 }
 
+static void vhost_region_nop(MemoryListener *listener,
+                             MemoryRegionSection *section)
+{
+}
+
 static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
                                     struct vhost_virtqueue *vq,
                                     unsigned idx, bool enable_log)
@@ -720,6 +733,18 @@ static void vhost_virtqueue_cleanup(struct vhost_dev *dev,
                               0, virtio_queue_get_desc_size(vdev, idx));
 }
 
+static void vhost_eventfd_add(MemoryListener *listener,
+                              MemoryRegionSection *section,
+                              bool match_data, uint64_t data, int fd)
+{
+}
+
+static void vhost_eventfd_del(MemoryListener *listener,
+                              MemoryRegionSection *section,
+                              bool match_data, uint64_t data, int fd)
+{
+}
+
 int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force)
 {
     uint64_t features;
@@ -744,13 +769,19 @@ int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force)
     hdev->features = features;
 
     hdev->memory_listener = (MemoryListener) {
+        .begin = vhost_begin,
+        .commit = vhost_commit,
         .region_add = vhost_region_add,
         .region_del = vhost_region_del,
+        .region_nop = vhost_region_nop,
         .log_start = vhost_log_start,
         .log_stop = vhost_log_stop,
         .log_sync = vhost_log_sync,
         .log_global_start = vhost_log_global_start,
         .log_global_stop = vhost_log_global_stop,
+        .eventfd_add = vhost_eventfd_add,
+        .eventfd_del = vhost_eventfd_del,
+        .priority = 10
     };
     hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions));
     hdev->n_mem_sections = 0;
@@ -759,7 +790,7 @@ int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force)
     hdev->log_size = 0;
     hdev->log_enabled = false;
     hdev->started = false;
-    memory_listener_register(&hdev->memory_listener);
+    memory_listener_register(&hdev->memory_listener, NULL);
     hdev->force = force;
     return 0;
 fail:
diff --git a/ioport.c b/ioport.c
index 36fa3a4..8a474d3 100644
--- a/ioport.c
+++ b/ioport.c
@@ -328,6 +328,7 @@ void portio_list_init(PortioList *piolist,
     piolist->ports = callbacks;
     piolist->nr = 0;
     piolist->regions = g_new0(MemoryRegion *, n);
+    piolist->aliases = g_new0(MemoryRegion *, n);
     piolist->address_space = NULL;
     piolist->opaque = opaque;
     piolist->name = name;
@@ -336,6 +337,7 @@ void portio_list_init(PortioList *piolist,
 void portio_list_destroy(PortioList *piolist)
 {
     g_free(piolist->regions);
+    g_free(piolist->aliases);
 }
 
 static void portio_list_add_1(PortioList *piolist,
@@ -345,7 +347,7 @@ static void portio_list_add_1(PortioList *piolist,
 {
     MemoryRegionPortio *pio;
     MemoryRegionOps *ops;
-    MemoryRegion *region;
+    MemoryRegion *region, *alias;
     unsigned i;
 
     /* Copy the sub-list and null-terminate it.  */
@@ -362,12 +364,20 @@ static void portio_list_add_1(PortioList *piolist,
     ops->old_portio = pio;
 
     region = g_new(MemoryRegion, 1);
+    alias = g_new(MemoryRegion, 1);
+    /*
+     * Use an alias so that the callback is called with an absolute address,
+     * rather than an offset relative to to start + off_low.
+     */
     memory_region_init_io(region, ops, piolist->opaque, piolist->name,
-                          off_high - off_low);
-    memory_region_set_offset(region, start + off_low);
+                          UINT64_MAX);
+    memory_region_init_alias(alias, piolist->name,
+                             region, start + off_low, off_high - off_low);
     memory_region_add_subregion(piolist->address_space,
-                                start + off_low, region);
-    piolist->regions[piolist->nr++] = region;
+                                start + off_low, alias);
+    piolist->regions[piolist->nr] = region;
+    piolist->aliases[piolist->nr] = alias;
+    ++piolist->nr;
 }
 
 void portio_list_add(PortioList *piolist,
@@ -409,15 +419,19 @@ void portio_list_add(PortioList *piolist,
 
 void portio_list_del(PortioList *piolist)
 {
-    MemoryRegion *mr;
+    MemoryRegion *mr, *alias;
     unsigned i;
 
     for (i = 0; i < piolist->nr; ++i) {
         mr = piolist->regions[i];
-        memory_region_del_subregion(piolist->address_space, mr);
+        alias = piolist->aliases[i];
+        memory_region_del_subregion(piolist->address_space, alias);
+        memory_region_destroy(alias);
         memory_region_destroy(mr);
         g_free((MemoryRegionOps *)mr->ops);
         g_free(mr);
+        g_free(alias);
         piolist->regions[i] = NULL;
+        piolist->aliases[i] = NULL;
     }
 }
diff --git a/ioport.h b/ioport.h
index ae3e9da..ab29c89 100644
--- a/ioport.h
+++ b/ioport.h
@@ -60,6 +60,7 @@ typedef struct PortioList {
     struct MemoryRegion *address_space;
     unsigned nr;
     struct MemoryRegion **regions;
+    struct MemoryRegion **aliases;
     void *opaque;
     const char *name;
 } PortioList;
diff --git a/kvm-all.c b/kvm-all.c
index e2cbc03..7119751 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -28,6 +28,7 @@
 #include "kvm.h"
 #include "bswap.h"
 #include "memory.h"
+#include "exec-memory.h"
 
 /* This check must be after config-host.h is included */
 #ifdef CONFIG_EVENTFD
@@ -674,6 +675,14 @@ static void kvm_set_phys_mem(MemoryRegionSection *section, bool add)
     }
 }
 
+static void kvm_begin(MemoryListener *listener)
+{
+}
+
+static void kvm_commit(MemoryListener *listener)
+{
+}
+
 static void kvm_region_add(MemoryListener *listener,
                            MemoryRegionSection *section)
 {
@@ -686,6 +695,11 @@ static void kvm_region_del(MemoryListener *listener,
     kvm_set_phys_mem(section, false);
 }
 
+static void kvm_region_nop(MemoryListener *listener,
+                           MemoryRegionSection *section)
+{
+}
+
 static void kvm_log_sync(MemoryListener *listener,
                          MemoryRegionSection *section)
 {
@@ -713,14 +727,95 @@ static void kvm_log_global_stop(struct MemoryListener *listener)
     assert(r >= 0);
 }
 
+static void kvm_mem_ioeventfd_add(MemoryRegionSection *section,
+                                  bool match_data, uint64_t data, int fd)
+{
+    int r;
+
+    assert(match_data && section->size == 4);
+
+    r = kvm_set_ioeventfd_mmio_long(fd, section->offset_within_address_space,
+                                    data, true);
+    if (r < 0) {
+        abort();
+    }
+}
+
+static void kvm_mem_ioeventfd_del(MemoryRegionSection *section,
+                                  bool match_data, uint64_t data, int fd)
+{
+    int r;
+
+    r = kvm_set_ioeventfd_mmio_long(fd, section->offset_within_address_space,
+                                    data, false);
+    if (r < 0) {
+        abort();
+    }
+}
+
+static void kvm_io_ioeventfd_add(MemoryRegionSection *section,
+                                 bool match_data, uint64_t data, int fd)
+{
+    int r;
+
+    assert(match_data && section->size == 2);
+
+    r = kvm_set_ioeventfd_pio_word(fd, section->offset_within_address_space,
+                                   data, true);
+    if (r < 0) {
+        abort();
+    }
+}
+
+static void kvm_io_ioeventfd_del(MemoryRegionSection *section,
+                                 bool match_data, uint64_t data, int fd)
+
+{
+    int r;
+
+    r = kvm_set_ioeventfd_pio_word(fd, section->offset_within_address_space,
+                                   data, false);
+    if (r < 0) {
+        abort();
+    }
+}
+
+static void kvm_eventfd_add(MemoryListener *listener,
+                            MemoryRegionSection *section,
+                            bool match_data, uint64_t data, int fd)
+{
+    if (section->address_space == get_system_memory()) {
+        kvm_mem_ioeventfd_add(section, match_data, data, fd);
+    } else {
+        kvm_io_ioeventfd_add(section, match_data, data, fd);
+    }
+}
+
+static void kvm_eventfd_del(MemoryListener *listener,
+                            MemoryRegionSection *section,
+                            bool match_data, uint64_t data, int fd)
+{
+    if (section->address_space == get_system_memory()) {
+        kvm_mem_ioeventfd_del(section, match_data, data, fd);
+    } else {
+        kvm_io_ioeventfd_del(section, match_data, data, fd);
+    }
+}
+
 static MemoryListener kvm_memory_listener = {
+    .begin = kvm_begin,
+    .commit = kvm_commit,
     .region_add = kvm_region_add,
     .region_del = kvm_region_del,
+    .region_nop = kvm_region_nop,
     .log_start = kvm_log_start,
     .log_stop = kvm_log_stop,
     .log_sync = kvm_log_sync,
     .log_global_start = kvm_log_global_start,
     .log_global_stop = kvm_log_global_stop,
+    .eventfd_add = kvm_eventfd_add,
+    .eventfd_del = kvm_eventfd_del,
+    .priority = 10,
 };
 
 static void kvm_handle_interrupt(CPUState *env, int mask)
@@ -965,7 +1060,7 @@ int kvm_init(void)
     }
 
     kvm_state = s;
-    memory_listener_register(&kvm_memory_listener);
+    memory_listener_register(&kvm_memory_listener, NULL);
 
     s->many_ioeventfds = kvm_check_many_ioeventfds();
 
diff --git a/memory.c b/memory.c
index 22816e2..6565e2e 100644
--- a/memory.c
+++ b/memory.c
@@ -27,8 +27,8 @@ unsigned memory_region_transaction_depth = 0;
 static bool memory_region_update_pending = false;
 static bool global_dirty_log = false;
 
-static QLIST_HEAD(, MemoryListener) memory_listeners
-    = QLIST_HEAD_INITIALIZER(memory_listeners);
+static QTAILQ_HEAD(memory_listeners, MemoryListener) memory_listeners
+    = QTAILQ_HEAD_INITIALIZER(memory_listeners);
 
 typedef struct AddrRange AddrRange;
 
@@ -82,6 +82,71 @@ static AddrRange addrrange_intersection(AddrRange r1, AddrRange r2)
     return addrrange_make(start, int128_sub(end, start));
 }
 
+enum ListenerDirection { Forward, Reverse };
+
+static bool memory_listener_match(MemoryListener *listener,
+                                  MemoryRegionSection *section)
+{
+    return !listener->address_space_filter
+        || listener->address_space_filter == section->address_space;
+}
+
+#define MEMORY_LISTENER_CALL_GLOBAL(_callback, _direction, _args...)    \
+    do {                                                                \
+        MemoryListener *_listener;                                      \
+                                                                        \
+        switch (_direction) {                                           \
+        case Forward:                                                   \
+            QTAILQ_FOREACH(_listener, &memory_listeners, link) {        \
+                _listener->_callback(_listener, ##_args);               \
+            }                                                           \
+            break;                                                      \
+        case Reverse:                                                   \
+            QTAILQ_FOREACH_REVERSE(_listener, &memory_listeners,        \
+                                   memory_listeners, link) {            \
+                _listener->_callback(_listener, ##_args);               \
+            }                                                           \
+            break;                                                      \
+        default:                                                        \
+            abort();                                                    \
+        }                                                               \
+    } while (0)
+
+#define MEMORY_LISTENER_CALL(_callback, _direction, _section, _args...) \
+    do {                                                                \
+        MemoryListener *_listener;                                      \
+                                                                        \
+        switch (_direction) {                                           \
+        case Forward:                                                   \
+            QTAILQ_FOREACH(_listener, &memory_listeners, link) {        \
+                if (memory_listener_match(_listener, _section)) {       \
+                    _listener->_callback(_listener, _section, ##_args); \
+                }                                                       \
+            }                                                           \
+            break;                                                      \
+        case Reverse:                                                   \
+            QTAILQ_FOREACH_REVERSE(_listener, &memory_listeners,        \
+                                   memory_listeners, link) {            \
+                if (memory_listener_match(_listener, _section)) {       \
+                    _listener->_callback(_listener, _section, ##_args); \
+                }                                                       \
+            }                                                           \
+            break;                                                      \
+        default:                                                        \
+            abort();                                                    \
+        }                                                               \
+    } while (0)
+
+#define MEMORY_LISTENER_UPDATE_REGION(fr, as, dir, callback)            \
+    MEMORY_LISTENER_CALL(callback, dir, (&(MemoryRegionSection) {       \
+        .mr = (fr)->mr,                                                 \
+        .address_space = (as)->root,                                    \
+        .offset_within_region = (fr)->offset_in_region,                 \
+        .size = int128_get64((fr)->addr.size),                          \
+        .offset_within_address_space = int128_get64((fr)->addr.start),  \
+        .readonly = (fr)->readonly,                                     \
+              }))
+
 struct CoalescedMemoryRange {
     AddrRange addr;
     QTAILQ_ENTRY(CoalescedMemoryRange) link;
@@ -158,22 +223,12 @@ typedef struct AddressSpaceOps AddressSpaceOps;
 
 /* A system address space - I/O, memory, etc. */
 struct AddressSpace {
-    const AddressSpaceOps *ops;
     MemoryRegion *root;
     FlatView current_map;
     int ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
 };
 
-struct AddressSpaceOps {
-    void (*range_add)(AddressSpace *as, FlatRange *fr);
-    void (*range_del)(AddressSpace *as, FlatRange *fr);
-    void (*log_start)(AddressSpace *as, FlatRange *fr);
-    void (*log_stop)(AddressSpace *as, FlatRange *fr);
-    void (*ioeventfd_add)(AddressSpace *as, MemoryRegionIoeventfd *fd);
-    void (*ioeventfd_del)(AddressSpace *as, MemoryRegionIoeventfd *fd);
-};
-
 #define FOR_EACH_FLAT_RANGE(var, view)          \
     for (var = (view)->ranges; var < (view)->ranges + (view)->nr; ++var)
 
@@ -305,74 +360,7 @@ static void access_with_adjusted_size(target_phys_addr_t addr,
     }
 }
 
-static void as_memory_range_add(AddressSpace *as, FlatRange *fr)
-{
-    MemoryRegionSection section = {
-        .mr = fr->mr,
-        .offset_within_address_space = int128_get64(fr->addr.start),
-        .offset_within_region = fr->offset_in_region,
-        .size = int128_get64(fr->addr.size),
-    };
-
-    cpu_register_physical_memory_log(&section, fr->readable, fr->readonly);
-}
-
-static void as_memory_range_del(AddressSpace *as, FlatRange *fr)
-{
-    MemoryRegionSection section = {
-        .mr = &io_mem_unassigned,
-        .offset_within_address_space = int128_get64(fr->addr.start),
-        .offset_within_region = int128_get64(fr->addr.start),
-        .size = int128_get64(fr->addr.size),
-    };
-
-    cpu_register_physical_memory_log(&section, true, false);
-}
-
-static void as_memory_log_start(AddressSpace *as, FlatRange *fr)
-{
-}
-
-static void as_memory_log_stop(AddressSpace *as, FlatRange *fr)
-{
-}
-
-static void as_memory_ioeventfd_add(AddressSpace *as, MemoryRegionIoeventfd *fd)
-{
-    int r;
-
-    assert(fd->match_data && int128_get64(fd->addr.size) == 4);
-
-    r = kvm_set_ioeventfd_mmio_long(fd->fd, int128_get64(fd->addr.start),
-                                    fd->data, true);
-    if (r < 0) {
-        abort();
-    }
-}
-
-static void as_memory_ioeventfd_del(AddressSpace *as, MemoryRegionIoeventfd *fd)
-{
-    int r;
-
-    r = kvm_set_ioeventfd_mmio_long(fd->fd, int128_get64(fd->addr.start),
-                                    fd->data, false);
-    if (r < 0) {
-        abort();
-    }
-}
-
-static const AddressSpaceOps address_space_ops_memory = {
-    .range_add = as_memory_range_add,
-    .range_del = as_memory_range_del,
-    .log_start = as_memory_log_start,
-    .log_stop = as_memory_log_stop,
-    .ioeventfd_add = as_memory_ioeventfd_add,
-    .ioeventfd_del = as_memory_ioeventfd_del,
-};
-
-static AddressSpace address_space_memory = {
-    .ops = &address_space_ops_memory,
-};
+static AddressSpace address_space_memory;
 
 static const MemoryRegionPortio *find_portio(MemoryRegion *mr, uint64_t offset,
                                              unsigned width, bool write)
@@ -401,17 +389,17 @@ static void memory_region_iorange_read(IORange *iorange,
 
         *data = ((uint64_t)1 << (width * 8)) - 1;
         if (mrp) {
-            *data = mrp->read(mr->opaque, offset + mr->offset);
+            *data = mrp->read(mr->opaque, offset);
         } else if (width == 2) {
             mrp = find_portio(mr, offset, 1, false);
             assert(mrp);
-            *data = mrp->read(mr->opaque, offset + mr->offset) |
-                    (mrp->read(mr->opaque, offset + mr->offset + 1) << 8);
+            *data = mrp->read(mr->opaque, offset) |
+                    (mrp->read(mr->opaque, offset + 1) << 8);
         }
         return;
     }
     *data = 0;
-    access_with_adjusted_size(offset + mr->offset, data, width,
+    access_with_adjusted_size(offset, data, width,
                               mr->ops->impl.min_access_size,
                               mr->ops->impl.max_access_size,
                               memory_region_read_accessor, mr);
@@ -428,73 +416,27 @@ static void memory_region_iorange_write(IORange *iorange,
         const MemoryRegionPortio *mrp = find_portio(mr, offset, width, true);
 
         if (mrp) {
-            mrp->write(mr->opaque, offset + mr->offset, data);
+            mrp->write(mr->opaque, offset, data);
         } else if (width == 2) {
             mrp = find_portio(mr, offset, 1, false);
             assert(mrp);
-            mrp->write(mr->opaque, offset + mr->offset, data & 0xff);
-            mrp->write(mr->opaque, offset + mr->offset + 1, data >> 8);
+            mrp->write(mr->opaque, offset, data & 0xff);
+            mrp->write(mr->opaque, offset + 1, data >> 8);
         }
         return;
     }
-    access_with_adjusted_size(offset + mr->offset, &data, width,
+    access_with_adjusted_size(offset, &data, width,
                               mr->ops->impl.min_access_size,
                               mr->ops->impl.max_access_size,
                               memory_region_write_accessor, mr);
 }
 
-static const IORangeOps memory_region_iorange_ops = {
+const IORangeOps memory_region_iorange_ops = {
     .read = memory_region_iorange_read,
     .write = memory_region_iorange_write,
 };
 
-static void as_io_range_add(AddressSpace *as, FlatRange *fr)
-{
-    iorange_init(&fr->mr->iorange, &memory_region_iorange_ops,
-                 int128_get64(fr->addr.start), int128_get64(fr->addr.size));
-    ioport_register(&fr->mr->iorange);
-}
-
-static void as_io_range_del(AddressSpace *as, FlatRange *fr)
-{
-    isa_unassign_ioport(int128_get64(fr->addr.start),
-                        int128_get64(fr->addr.size));
-}
-
-static void as_io_ioeventfd_add(AddressSpace *as, MemoryRegionIoeventfd *fd)
-{
-    int r;
-
-    assert(fd->match_data && int128_get64(fd->addr.size) == 2);
-
-    r = kvm_set_ioeventfd_pio_word(fd->fd, int128_get64(fd->addr.start),
-                                   fd->data, true);
-    if (r < 0) {
-        abort();
-    }
-}
-
-static void as_io_ioeventfd_del(AddressSpace *as, MemoryRegionIoeventfd *fd)
-{
-    int r;
-
-    r = kvm_set_ioeventfd_pio_word(fd->fd, int128_get64(fd->addr.start),
-                                   fd->data, false);
-    if (r < 0) {
-        abort();
-    }
-}
-
-static const AddressSpaceOps address_space_ops_io = {
-    .range_add = as_io_range_add,
-    .range_del = as_io_range_del,
-    .ioeventfd_add = as_io_ioeventfd_add,
-    .ioeventfd_del = as_io_ioeventfd_del,
-};
-
-static AddressSpace address_space_io = {
-    .ops = &address_space_ops_io,
-};
+static AddressSpace address_space_io;
 
 static AddressSpace *memory_region_to_address_space(MemoryRegion *mr)
 {
@@ -621,6 +563,8 @@ static void address_space_add_del_ioeventfds(AddressSpace *as,
                                              unsigned fds_old_nb)
 {
     unsigned iold, inew;
+    MemoryRegionIoeventfd *fd;
+    MemoryRegionSection section;
 
     /* Generate a symmetric difference of the old and new fd sets, adding
      * and deleting as necessary.
@@ -632,13 +576,27 @@ static void address_space_add_del_ioeventfds(AddressSpace *as,
             && (inew == fds_new_nb
                 || memory_region_ioeventfd_before(fds_old[iold],
                                                   fds_new[inew]))) {
-            as->ops->ioeventfd_del(as, &fds_old[iold]);
+            fd = &fds_old[iold];
+            section = (MemoryRegionSection) {
+                .address_space = as->root,
+                .offset_within_address_space = int128_get64(fd->addr.start),
+                .size = int128_get64(fd->addr.size),
+            };
+            MEMORY_LISTENER_CALL(eventfd_del, Forward, &section,
+                                 fd->match_data, fd->data, fd->fd);
             ++iold;
         } else if (inew < fds_new_nb
                    && (iold == fds_old_nb
                        || memory_region_ioeventfd_before(fds_new[inew],
                                                          fds_old[iold]))) {
-            as->ops->ioeventfd_add(as, &fds_new[inew]);
+            fd = &fds_new[inew];
+            section = (MemoryRegionSection) {
+                .address_space = as->root,
+                .offset_within_address_space = int128_get64(fd->addr.start),
+                .size = int128_get64(fd->addr.size),
+            };
+            MEMORY_LISTENER_CALL(eventfd_add, Reverse, &section,
+                                 fd->match_data, fd->data, fd->fd);
             ++inew;
         } else {
             ++iold;
@@ -678,32 +636,6 @@ static void address_space_update_ioeventfds(AddressSpace *as)
     as->ioeventfd_nb = ioeventfd_nb;
 }
 
-typedef void ListenerCallback(MemoryListener *listener,
-                              MemoryRegionSection *mrs);
-
-/* Want "void (&MemoryListener::*callback)(const MemoryRegionSection& s)" */
-static void memory_listener_update_region(FlatRange *fr, AddressSpace *as,
-                                          size_t callback_offset)
-{
-    MemoryRegionSection section = {
-        .mr = fr->mr,
-        .address_space = as->root,
-        .offset_within_region = fr->offset_in_region,
-        .size = int128_get64(fr->addr.size),
-        .offset_within_address_space = int128_get64(fr->addr.start),
-    };
-    MemoryListener *listener;
-
-    QLIST_FOREACH(listener, &memory_listeners, link) {
-        ListenerCallback *callback
-            = *(ListenerCallback **)((void *)listener + callback_offset);
-        callback(listener, &section);
-    }
-}
-
-#define MEMORY_LISTENER_UPDATE_REGION(fr, as, callback) \
-    memory_listener_update_region(fr, as, offsetof(MemoryListener, callback))
-
 static void address_space_update_topology_pass(AddressSpace *as,
                                                FlatView old_view,
                                                FlatView new_view,
@@ -736,8 +668,7 @@ static void address_space_update_topology_pass(AddressSpace *as,
             /* In old, but (not in new, or in new but attributes changed). */
 
             if (!adding) {
-                MEMORY_LISTENER_UPDATE_REGION(frold, as, region_del);
-                as->ops->range_del(as, frold);
+                MEMORY_LISTENER_UPDATE_REGION(frold, as, Reverse, region_del);
             }
 
             ++iold;
@@ -745,12 +676,11 @@ static void address_space_update_topology_pass(AddressSpace *as,
             /* In both (logging may have changed) */
 
             if (adding) {
+                MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, region_nop);
                 if (frold->dirty_log_mask && !frnew->dirty_log_mask) {
-                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, log_stop);
-                    as->ops->log_stop(as, frnew);
+                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, Reverse, log_stop);
                 } else if (frnew->dirty_log_mask && !frold->dirty_log_mask) {
-                    as->ops->log_start(as, frnew);
-                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, log_start);
+                    MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, log_start);
                 }
             }
 
@@ -760,8 +690,7 @@ static void address_space_update_topology_pass(AddressSpace *as,
             /* In new */
 
             if (adding) {
-                as->ops->range_add(as, frnew);
-                MEMORY_LISTENER_UPDATE_REGION(frnew, as, region_add);
+                MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, region_add);
             }
 
             ++inew;
@@ -794,6 +723,8 @@ static void memory_region_update_topology(MemoryRegion *mr)
         return;
     }
 
+    MEMORY_LISTENER_CALL_GLOBAL(begin, Forward);
+
     if (address_space_memory.root) {
         address_space_update_topology(&address_space_memory);
     }
@@ -801,6 +732,8 @@ static void memory_region_update_topology(MemoryRegion *mr)
         address_space_update_topology(&address_space_io);
     }
 
+    MEMORY_LISTENER_CALL_GLOBAL(commit, Forward);
+
     memory_region_update_pending = false;
 }
 
@@ -863,7 +796,6 @@ void memory_region_init(MemoryRegion *mr,
         mr->size = int128_2_64();
     }
     mr->addr = 0;
-    mr->offset = 0;
     mr->subpage = false;
     mr->enabled = true;
     mr->terminates = false;
@@ -925,7 +857,7 @@ static uint64_t memory_region_dispatch_read1(MemoryRegion *mr,
     }
 
     /* FIXME: support unaligned access */
-    access_with_adjusted_size(addr + mr->offset, &data, size,
+    access_with_adjusted_size(addr, &data, size,
                               mr->ops->impl.min_access_size,
                               mr->ops->impl.max_access_size,
                               memory_region_read_accessor, mr);
@@ -979,7 +911,7 @@ static void memory_region_dispatch_write(MemoryRegion *mr,
     }
 
     /* FIXME: support unaligned access */
-    access_with_adjusted_size(addr + mr->offset, &data, size,
+    access_with_adjusted_size(addr, &data, size,
                               mr->ops->impl.min_access_size,
                               mr->ops->impl.max_access_size,
                               memory_region_write_accessor, mr);
@@ -1122,11 +1054,6 @@ bool memory_region_is_rom(MemoryRegion *mr)
     return mr->ram && mr->readonly;
 }
 
-void memory_region_set_offset(MemoryRegion *mr, target_phys_addr_t offset)
-{
-    mr->offset = offset;
-}
-
 void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client)
 {
     uint8_t mask = 1 << client;
@@ -1156,7 +1083,8 @@ void memory_region_sync_dirty_bitmap(MemoryRegion *mr)
 
     FOR_EACH_FLAT_RANGE(fr, &address_space_memory.current_map) {
         if (fr->mr == mr) {
-            MEMORY_LISTENER_UPDATE_REGION(fr, &address_space_memory, log_sync);
+            MEMORY_LISTENER_UPDATE_REGION(fr, &address_space_memory,
+                                          Forward, log_sync);
         }
     }
 }
@@ -1474,6 +1402,7 @@ MemoryRegionSection memory_region_find(MemoryRegion *address_space,
                                                         fr->addr.start));
     ret.size = int128_get64(range.size);
     ret.offset_within_address_space = int128_get64(range.start);
+    ret.readonly = fr->readonly;
     return ret;
 }
 
@@ -1483,30 +1412,20 @@ void memory_global_sync_dirty_bitmap(MemoryRegion *address_space)
     FlatRange *fr;
 
     FOR_EACH_FLAT_RANGE(fr, &as->current_map) {
-        MEMORY_LISTENER_UPDATE_REGION(fr, as, log_sync);
+        MEMORY_LISTENER_UPDATE_REGION(fr, as, Forward, log_sync);
     }
 }
 
 void memory_global_dirty_log_start(void)
 {
-    MemoryListener *listener;
-
-    cpu_physical_memory_set_dirty_tracking(1);
     global_dirty_log = true;
-    QLIST_FOREACH(listener, &memory_listeners, link) {
-        listener->log_global_start(listener);
-    }
+    MEMORY_LISTENER_CALL_GLOBAL(log_global_start, Forward);
 }
 
 void memory_global_dirty_log_stop(void)
 {
-    MemoryListener *listener;
-
     global_dirty_log = false;
-    QLIST_FOREACH(listener, &memory_listeners, link) {
-        listener->log_global_stop(listener);
-    }
-    cpu_physical_memory_set_dirty_tracking(0);
+    MEMORY_LISTENER_CALL_GLOBAL(log_global_stop, Reverse);
 }
 
 static void listener_add_address_space(MemoryListener *listener,
@@ -1524,21 +1443,36 @@ static void listener_add_address_space(MemoryListener *listener,
             .offset_within_region = fr->offset_in_region,
             .size = int128_get64(fr->addr.size),
             .offset_within_address_space = int128_get64(fr->addr.start),
+            .readonly = fr->readonly,
         };
         listener->region_add(listener, &section);
     }
 }
 
-void memory_listener_register(MemoryListener *listener)
+void memory_listener_register(MemoryListener *listener, MemoryRegion *filter)
 {
-    QLIST_INSERT_HEAD(&memory_listeners, listener, link);
+    MemoryListener *other = NULL;
+
+    listener->address_space_filter = filter;
+    if (QTAILQ_EMPTY(&memory_listeners)
+        || listener->priority >= QTAILQ_LAST(&memory_listeners,
+                                             memory_listeners)->priority) {
+        QTAILQ_INSERT_TAIL(&memory_listeners, listener, link);
+    } else {
+        QTAILQ_FOREACH(other, &memory_listeners, link) {
+            if (listener->priority < other->priority) {
+                break;
+            }
+        }
+        QTAILQ_INSERT_BEFORE(other, listener, link);
+    }
     listener_add_address_space(listener, &address_space_memory);
     listener_add_address_space(listener, &address_space_io);
 }
 
 void memory_listener_unregister(MemoryListener *listener)
 {
-    QLIST_REMOVE(listener, link);
+    QTAILQ_REMOVE(&memory_listeners, listener, link);
 }
 
 void set_system_memory_map(MemoryRegion *mr)
diff --git a/memory.h b/memory.h
index 4cf8d2f..b7bccd1 100644
--- a/memory.h
+++ b/memory.h
@@ -115,7 +115,6 @@ struct MemoryRegion {
     MemoryRegion *parent;
     Int128 size;
     target_phys_addr_t addr;
-    target_phys_addr_t offset;
     void (*destructor)(MemoryRegion *mr);
     ram_addr_t ram_addr;
     IORange iorange;
@@ -161,6 +160,7 @@ typedef struct MemoryRegionSection MemoryRegionSection;
  * @size: the size of the section; will not exceed @mr's boundaries
  * @offset_within_address_space: the address of the first byte of the section
  *     relative to the region's address space
+ * @readonly: writes to this section are ignored
  */
 struct MemoryRegionSection {
     MemoryRegion *mr;
@@ -168,6 +168,7 @@ struct MemoryRegionSection {
     target_phys_addr_t offset_within_region;
     uint64_t size;
     target_phys_addr_t offset_within_address_space;
+    bool readonly;
 };
 
 typedef struct MemoryListener MemoryListener;
@@ -179,14 +180,24 @@ typedef struct MemoryListener MemoryListener;
  * Use with memory_listener_register() and memory_listener_unregister().
  */
 struct MemoryListener {
+    void (*begin)(MemoryListener *listener);
+    void (*commit)(MemoryListener *listener);
     void (*region_add)(MemoryListener *listener, MemoryRegionSection *section);
     void (*region_del)(MemoryListener *listener, MemoryRegionSection *section);
+    void (*region_nop)(MemoryListener *listener, MemoryRegionSection *section);
     void (*log_start)(MemoryListener *listener, MemoryRegionSection *section);
     void (*log_stop)(MemoryListener *listener, MemoryRegionSection *section);
     void (*log_sync)(MemoryListener *listener, MemoryRegionSection *section);
     void (*log_global_start)(MemoryListener *listener);
     void (*log_global_stop)(MemoryListener *listener);
-    QLIST_ENTRY(MemoryListener) link;
+    void (*eventfd_add)(MemoryListener *listener, MemoryRegionSection *section,
+                        bool match_data, uint64_t data, int fd);
+    void (*eventfd_del)(MemoryListener *listener, MemoryRegionSection *section,
+                        bool match_data, uint64_t data, int fd);
+    /* Lower = earlier (during add), later (during del) */
+    unsigned priority;
+    MemoryRegion *address_space_filter;
+    QTAILQ_ENTRY(MemoryListener) link;
 };
 
 /**
@@ -359,14 +370,6 @@ bool memory_region_is_rom(MemoryRegion *mr);
 void *memory_region_get_ram_ptr(MemoryRegion *mr);
 
 /**
- * memory_region_set_offset: Sets an offset to be added to MemoryRegionOps
- *                           callbacks.
- *
- * This function is deprecated and should not be used in new code.
- */
-void memory_region_set_offset(MemoryRegion *mr, target_phys_addr_t offset);
-
-/**
  * memory_region_set_log: Turn dirty logging on or off for a region.
  *
  * Turns dirty logging on or off for a specified client (display, migration).
@@ -686,8 +689,9 @@ void memory_region_transaction_commit(void);
  *                           space
  *
  * @listener: an object containing the callbacks to be called
+ * @filter: if non-%NULL, only regions in this address space will be observed
  */
-void memory_listener_register(MemoryListener *listener);
+void memory_listener_register(MemoryListener *listener, MemoryRegion *filter);
 
 /**
  * memory_listener_unregister: undo the effect of memory_listener_register()
diff --git a/xen-all.c b/xen-all.c
index b0ed1ed..6cef506 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -392,6 +392,14 @@ static void xen_set_memory(struct MemoryListener *listener,
     }
 }
 
+static void xen_begin(MemoryListener *listener)
+{
+}
+
+static void xen_commit(MemoryListener *listener)
+{
+}
+
 static void xen_region_add(MemoryListener *listener,
                            MemoryRegionSection *section)
 {
@@ -404,6 +412,11 @@ static void xen_region_del(MemoryListener *listener,
     xen_set_memory(listener, section, false);
 }
 
+static void xen_region_nop(MemoryListener *listener,
+                           MemoryRegionSection *section)
+{
+}
+
 static void xen_sync_dirty_bitmap(XenIOState *state,
                                   target_phys_addr_t start_addr,
                                   ram_addr_t size)
@@ -485,14 +498,32 @@ static void xen_log_global_stop(MemoryListener *listener)
 {
 }
 
+static void xen_eventfd_add(MemoryListener *listener,
+                            MemoryRegionSection *section,
+                            bool match_data, uint64_t data, int fd)
+{
+}
+
+static void xen_eventfd_del(MemoryListener *listener,
+                            MemoryRegionSection *section,
+                            bool match_data, uint64_t data, int fd)
+{
+}
+
 static MemoryListener xen_memory_listener = {
+    .begin = xen_begin,
+    .commit = xen_commit,
     .region_add = xen_region_add,
     .region_del = xen_region_del,
+    .region_nop = xen_region_nop,
     .log_start = xen_log_start,
     .log_stop = xen_log_stop,
     .log_sync = xen_log_sync,
     .log_global_start = xen_log_global_start,
     .log_global_stop = xen_log_global_stop,
+    .eventfd_add = xen_eventfd_add,
+    .eventfd_del = xen_eventfd_del,
+    .priority = 10,
 };
 
 /* VCPU Operations, MMIO, IO ring ... */
@@ -975,7 +1006,7 @@ int xen_hvm_init(void)
 
     state->memory_listener = xen_memory_listener;
     QLIST_INIT(&state->physmap);
-    memory_listener_register(&state->memory_listener);
+    memory_listener_register(&state->memory_listener, get_system_memory());
     state->log_for_dirtybit = NULL;
 
     /* Initialize backend core & drivers */