qemu

memory.h (111586B)

---

 /*
  * Physical memory management API
  *
  * Copyright 2011 Red Hat, Inc. and/or its affiliates
  *
  * Authors:
  *  Avi Kivity <avi@redhat.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2.  See
  * the COPYING file in the top-level directory.
  *
  */
 
 #ifndef MEMORY_H
 #define MEMORY_H
 
 #ifndef CONFIG_USER_ONLY
 
 #include "exec/cpu-common.h"
 #include "exec/hwaddr.h"
 #include "exec/memattrs.h"
 #include "exec/memop.h"
 #include "exec/ramlist.h"
 #include "qemu/bswap.h"
 #include "qemu/queue.h"
 #include "qemu/int128.h"
 #include "qemu/notify.h"
 #include "qom/object.h"
 #include "qemu/rcu.h"
 
 #define RAM_ADDR_INVALID (~(ram_addr_t)0)
 
 #define MAX_PHYS_ADDR_SPACE_BITS 62
 #define MAX_PHYS_ADDR            (((hwaddr)1 << MAX_PHYS_ADDR_SPACE_BITS) - 1)
 
 #define TYPE_MEMORY_REGION "memory-region"
 DECLARE_INSTANCE_CHECKER(MemoryRegion, MEMORY_REGION,
                          TYPE_MEMORY_REGION)
 
 #define TYPE_IOMMU_MEMORY_REGION "iommu-memory-region"
 typedef struct IOMMUMemoryRegionClass IOMMUMemoryRegionClass;
 DECLARE_OBJ_CHECKERS(IOMMUMemoryRegion, IOMMUMemoryRegionClass,
                      IOMMU_MEMORY_REGION, TYPE_IOMMU_MEMORY_REGION)
 
 #define TYPE_RAM_DISCARD_MANAGER "qemu:ram-discard-manager"
 typedef struct RamDiscardManagerClass RamDiscardManagerClass;
 typedef struct RamDiscardManager RamDiscardManager;
 DECLARE_OBJ_CHECKERS(RamDiscardManager, RamDiscardManagerClass,
                      RAM_DISCARD_MANAGER, TYPE_RAM_DISCARD_MANAGER);
 
 #ifdef CONFIG_FUZZ
 void fuzz_dma_read_cb(size_t addr,
                       size_t len,
                       MemoryRegion *mr);
 #else
 static inline void fuzz_dma_read_cb(size_t addr,
                                     size_t len,
                                     MemoryRegion *mr)
 {
     /* Do Nothing */
 }
 #endif
 
 /* Possible bits for global_dirty_log_{start|stop} */
 
 /* Dirty tracking enabled because migration is running */
 #define GLOBAL_DIRTY_MIGRATION  (1U << 0)
 
 /* Dirty tracking enabled because measuring dirty rate */
 #define GLOBAL_DIRTY_DIRTY_RATE (1U << 1)
 
 /* Dirty tracking enabled because dirty limit */
 #define GLOBAL_DIRTY_LIMIT      (1U << 2)
 
 #define GLOBAL_DIRTY_MASK  (0x7)
 
 extern unsigned int global_dirty_tracking;
 
 typedef struct MemoryRegionOps MemoryRegionOps;
 
 struct ReservedRegion {
     hwaddr low;
     hwaddr high;
     unsigned type;
 };
 
 /**
  * struct MemoryRegionSection: describes a fragment of a #MemoryRegion
  *
  * @mr: the region, or %NULL if empty
  * @fv: the flat view of the address space the region is mapped in
  * @offset_within_region: the beginning of the section, relative to @mr's start
  * @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
  * @nonvolatile: this section is non-volatile
  */
 struct MemoryRegionSection {
     Int128 size;
     MemoryRegion *mr;
     FlatView *fv;
     hwaddr offset_within_region;
     hwaddr offset_within_address_space;
     bool readonly;
     bool nonvolatile;
 };
 
 typedef struct IOMMUTLBEntry IOMMUTLBEntry;
 
 /* See address_space_translate: bit 0 is read, bit 1 is write.  */
 typedef enum {
     IOMMU_NONE = 0,
     IOMMU_RO   = 1,
     IOMMU_WO   = 2,
     IOMMU_RW   = 3,
 } IOMMUAccessFlags;
 
 #define IOMMU_ACCESS_FLAG(r, w) (((r) ? IOMMU_RO : 0) | ((w) ? IOMMU_WO : 0))
 
 struct IOMMUTLBEntry {
     AddressSpace    *target_as;
     hwaddr           iova;
     hwaddr           translated_addr;
     hwaddr           addr_mask;  /* 0xfff = 4k translation */
     IOMMUAccessFlags perm;
 };
 
 /*
  * Bitmap for different IOMMUNotifier capabilities. Each notifier can
  * register with one or multiple IOMMU Notifier capability bit(s).
  */
 typedef enum {
     IOMMU_NOTIFIER_NONE = 0,
     /* Notify cache invalidations */
     IOMMU_NOTIFIER_UNMAP = 0x1,
     /* Notify entry changes (newly created entries) */
     IOMMU_NOTIFIER_MAP = 0x2,
     /* Notify changes on device IOTLB entries */
     IOMMU_NOTIFIER_DEVIOTLB_UNMAP = 0x04,
 } IOMMUNotifierFlag;
 
 #define IOMMU_NOTIFIER_IOTLB_EVENTS (IOMMU_NOTIFIER_MAP | IOMMU_NOTIFIER_UNMAP)
 #define IOMMU_NOTIFIER_DEVIOTLB_EVENTS IOMMU_NOTIFIER_DEVIOTLB_UNMAP
 #define IOMMU_NOTIFIER_ALL (IOMMU_NOTIFIER_IOTLB_EVENTS | \
                             IOMMU_NOTIFIER_DEVIOTLB_EVENTS)
 
 struct IOMMUNotifier;
 typedef void (*IOMMUNotify)(struct IOMMUNotifier *notifier,
                             IOMMUTLBEntry *data);
 
 struct IOMMUNotifier {
     IOMMUNotify notify;
     IOMMUNotifierFlag notifier_flags;
     /* Notify for address space range start <= addr <= end */
     hwaddr start;
     hwaddr end;
     int iommu_idx;
     QLIST_ENTRY(IOMMUNotifier) node;
 };
 typedef struct IOMMUNotifier IOMMUNotifier;
 
 typedef struct IOMMUTLBEvent {
     IOMMUNotifierFlag type;
     IOMMUTLBEntry entry;
 } IOMMUTLBEvent;
 
 /* RAM is pre-allocated and passed into qemu_ram_alloc_from_ptr */
 #define RAM_PREALLOC   (1 << 0)
 
 /* RAM is mmap-ed with MAP_SHARED */
 #define RAM_SHARED     (1 << 1)
 
 /* Only a portion of RAM (used_length) is actually used, and migrated.
  * Resizing RAM while migrating can result in the migration being canceled.
  */
 #define RAM_RESIZEABLE (1 << 2)
 
 /* UFFDIO_ZEROPAGE is available on this RAMBlock to atomically
  * zero the page and wake waiting processes.
  * (Set during postcopy)
  */
 #define RAM_UF_ZEROPAGE (1 << 3)
 
 /* RAM can be migrated */
 #define RAM_MIGRATABLE (1 << 4)
 
 /* RAM is a persistent kind memory */
 #define RAM_PMEM (1 << 5)
 
 
 /*
  * UFFDIO_WRITEPROTECT is used on this RAMBlock to
  * support 'write-tracking' migration type.
  * Implies ram_state->ram_wt_enabled.
  */
 #define RAM_UF_WRITEPROTECT (1 << 6)
 
 /*
  * RAM is mmap-ed with MAP_NORESERVE. When set, reserving swap space (or huge
  * pages if applicable) is skipped: will bail out if not supported. When not
  * set, the OS will do the reservation, if supported for the memory type.
  */
 #define RAM_NORESERVE (1 << 7)
 
 /* RAM that isn't accessible through normal means. */
 #define RAM_PROTECTED (1 << 8)
 
 static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
                                        IOMMUNotifierFlag flags,
                                        hwaddr start, hwaddr end,
                                        int iommu_idx)
 {
     n->notify = fn;
     n->notifier_flags = flags;
     n->start = start;
     n->end = end;
     n->iommu_idx = iommu_idx;
 }
 
 /*
  * Memory region callbacks
  */
 struct MemoryRegionOps {
     /* Read from the memory region. @addr is relative to @mr; @size is
      * in bytes. */
     uint64_t (*read)(void *opaque,
                      hwaddr addr,
                      unsigned size);
     /* Write to the memory region. @addr is relative to @mr; @size is
      * in bytes. */
     void (*write)(void *opaque,
                   hwaddr addr,
                   uint64_t data,
                   unsigned size);
 
     MemTxResult (*read_with_attrs)(void *opaque,
                                    hwaddr addr,
                                    uint64_t *data,
                                    unsigned size,
                                    MemTxAttrs attrs);
     MemTxResult (*write_with_attrs)(void *opaque,
                                     hwaddr addr,
                                     uint64_t data,
                                     unsigned size,
                                     MemTxAttrs attrs);
 
     enum device_endian endianness;
     /* Guest-visible constraints: */
     struct {
         /* If nonzero, specify bounds on access sizes beyond which a machine
          * check is thrown.
          */
         unsigned min_access_size;
         unsigned max_access_size;
         /* If true, unaligned accesses are supported.  Otherwise unaligned
          * accesses throw machine checks.
          */
          bool unaligned;
         /*
          * If present, and returns #false, the transaction is not accepted
          * by the device (and results in machine dependent behaviour such
          * as a machine check exception).
          */
         bool (*accepts)(void *opaque, hwaddr addr,
                         unsigned size, bool is_write,
                         MemTxAttrs attrs);
     } valid;
     /* Internal implementation constraints: */
     struct {
         /* If nonzero, specifies the minimum size implemented.  Smaller sizes
          * will be rounded upwards and a partial result will be returned.
          */
         unsigned min_access_size;
         /* If nonzero, specifies the maximum size implemented.  Larger sizes
          * will be done as a series of accesses with smaller sizes.
          */
         unsigned max_access_size;
         /* If true, unaligned accesses are supported.  Otherwise all accesses
          * are converted to (possibly multiple) naturally aligned accesses.
          */
         bool unaligned;
     } impl;
 };
 
 typedef struct MemoryRegionClass {
     /* private */
     ObjectClass parent_class;
 } MemoryRegionClass;
 
 
 enum IOMMUMemoryRegionAttr {
     IOMMU_ATTR_SPAPR_TCE_FD
 };
 
 /*
  * IOMMUMemoryRegionClass:
  *
  * All IOMMU implementations need to subclass TYPE_IOMMU_MEMORY_REGION
  * and provide an implementation of at least the @translate method here
  * to handle requests to the memory region. Other methods are optional.
  *
  * The IOMMU implementation must use the IOMMU notifier infrastructure
  * to report whenever mappings are changed, by calling
  * memory_region_notify_iommu() (or, if necessary, by calling
  * memory_region_notify_iommu_one() for each registered notifier).
  *
  * Conceptually an IOMMU provides a mapping from input address
  * to an output TLB entry. If the IOMMU is aware of memory transaction
  * attributes and the output TLB entry depends on the transaction
  * attributes, we represent this using IOMMU indexes. Each index
  * selects a particular translation table that the IOMMU has:
  *
  *   @attrs_to_index returns the IOMMU index for a set of transaction attributes
  *
  *   @translate takes an input address and an IOMMU index
  *
  * and the mapping returned can only depend on the input address and the
  * IOMMU index.
  *
  * Most IOMMUs don't care about the transaction attributes and support
  * only a single IOMMU index. A more complex IOMMU might have one index
  * for secure transactions and one for non-secure transactions.
  */
 struct IOMMUMemoryRegionClass {
     /* private: */
     MemoryRegionClass parent_class;
 
     /* public: */
     /**
      * @translate:
      *
      * Return a TLB entry that contains a given address.
      *
      * The IOMMUAccessFlags indicated via @flag are optional and may
      * be specified as IOMMU_NONE to indicate that the caller needs
      * the full translation information for both reads and writes. If
      * the access flags are specified then the IOMMU implementation
      * may use this as an optimization, to stop doing a page table
      * walk as soon as it knows that the requested permissions are not
      * allowed. If IOMMU_NONE is passed then the IOMMU must do the
      * full page table walk and report the permissions in the returned
      * IOMMUTLBEntry. (Note that this implies that an IOMMU may not
      * return different mappings for reads and writes.)
      *
      * The returned information remains valid while the caller is
      * holding the big QEMU lock or is inside an RCU critical section;
      * if the caller wishes to cache the mapping beyond that it must
      * register an IOMMU notifier so it can invalidate its cached
      * information when the IOMMU mapping changes.
      *
      * @iommu: the IOMMUMemoryRegion
      *
      * @hwaddr: address to be translated within the memory region
      *
      * @flag: requested access permission
      *
      * @iommu_idx: IOMMU index for the translation
      */
     IOMMUTLBEntry (*translate)(IOMMUMemoryRegion *iommu, hwaddr addr,
                                IOMMUAccessFlags flag, int iommu_idx);
     /**
      * @get_min_page_size:
      *
      * Returns minimum supported page size in bytes.
      *
      * If this method is not provided then the minimum is assumed to
      * be TARGET_PAGE_SIZE.
      *
      * @iommu: the IOMMUMemoryRegion
      */
     uint64_t (*get_min_page_size)(IOMMUMemoryRegion *iommu);
     /**
      * @notify_flag_changed:
      *
      * Called when IOMMU Notifier flag changes (ie when the set of
      * events which IOMMU users are requesting notification for changes).
      * Optional method -- need not be provided if the IOMMU does not
      * need to know exactly which events must be notified.
      *
      * @iommu: the IOMMUMemoryRegion
      *
      * @old_flags: events which previously needed to be notified
      *
      * @new_flags: events which now need to be notified
      *
      * Returns 0 on success, or a negative errno; in particular
      * returns -EINVAL if the new flag bitmap is not supported by the
      * IOMMU memory region. In case of failure, the error object
      * must be created
      */
     int (*notify_flag_changed)(IOMMUMemoryRegion *iommu,
                                IOMMUNotifierFlag old_flags,
                                IOMMUNotifierFlag new_flags,
                                Error **errp);
     /**
      * @replay:
      *
      * Called to handle memory_region_iommu_replay().
      *
      * The default implementation of memory_region_iommu_replay() is to
      * call the IOMMU translate method for every page in the address space
      * with flag == IOMMU_NONE and then call the notifier if translate
      * returns a valid mapping. If this method is implemented then it
      * overrides the default behaviour, and must provide the full semantics
      * of memory_region_iommu_replay(), by calling @notifier for every
      * translation present in the IOMMU.
      *
      * Optional method -- an IOMMU only needs to provide this method
      * if the default is inefficient or produces undesirable side effects.
      *
      * Note: this is not related to record-and-replay functionality.
      */
     void (*replay)(IOMMUMemoryRegion *iommu, IOMMUNotifier *notifier);
 
     /**
      * @get_attr:
      *
      * Get IOMMU misc attributes. This is an optional method that
      * can be used to allow users of the IOMMU to get implementation-specific
      * information. The IOMMU implements this method to handle calls
      * by IOMMU users to memory_region_iommu_get_attr() by filling in
      * the arbitrary data pointer for any IOMMUMemoryRegionAttr values that
      * the IOMMU supports. If the method is unimplemented then
      * memory_region_iommu_get_attr() will always return -EINVAL.
      *
      * @iommu: the IOMMUMemoryRegion
      *
      * @attr: attribute being queried
      *
      * @data: memory to fill in with the attribute data
      *
      * Returns 0 on success, or a negative errno; in particular
      * returns -EINVAL for unrecognized or unimplemented attribute types.
      */
     int (*get_attr)(IOMMUMemoryRegion *iommu, enum IOMMUMemoryRegionAttr attr,
                     void *data);
 
     /**
      * @attrs_to_index:
      *
      * Return the IOMMU index to use for a given set of transaction attributes.
      *
      * Optional method: if an IOMMU only supports a single IOMMU index then
      * the default implementation of memory_region_iommu_attrs_to_index()
      * will return 0.
      *
      * The indexes supported by an IOMMU must be contiguous, starting at 0.
      *
      * @iommu: the IOMMUMemoryRegion
      * @attrs: memory transaction attributes
      */
     int (*attrs_to_index)(IOMMUMemoryRegion *iommu, MemTxAttrs attrs);
 
     /**
      * @num_indexes:
      *
      * Return the number of IOMMU indexes this IOMMU supports.
      *
      * Optional method: if this method is not provided, then
      * memory_region_iommu_num_indexes() will return 1, indicating that
      * only a single IOMMU index is supported.
      *
      * @iommu: the IOMMUMemoryRegion
      */
     int (*num_indexes)(IOMMUMemoryRegion *iommu);
 
     /**
      * @iommu_set_page_size_mask:
      *
      * Restrict the page size mask that can be supported with a given IOMMU
      * memory region. Used for example to propagate host physical IOMMU page
      * size mask limitations to the virtual IOMMU.
      *
      * Optional method: if this method is not provided, then the default global
      * page mask is used.
      *
      * @iommu: the IOMMUMemoryRegion
      *
      * @page_size_mask: a bitmask of supported page sizes. At least one bit,
      * representing the smallest page size, must be set. Additional set bits
      * represent supported block sizes. For example a host physical IOMMU that
      * uses page tables with a page size of 4kB, and supports 2MB and 4GB
      * blocks, will set mask 0x40201000. A granule of 4kB with indiscriminate
      * block sizes is specified with mask 0xfffffffffffff000.
      *
      * Returns 0 on success, or a negative error. In case of failure, the error
      * object must be created.
      */
      int (*iommu_set_page_size_mask)(IOMMUMemoryRegion *iommu,
                                      uint64_t page_size_mask,
                                      Error **errp);
 };
 
 typedef struct RamDiscardListener RamDiscardListener;
 typedef int (*NotifyRamPopulate)(RamDiscardListener *rdl,
                                  MemoryRegionSection *section);
 typedef void (*NotifyRamDiscard)(RamDiscardListener *rdl,
                                  MemoryRegionSection *section);
 
 struct RamDiscardListener {
     /*
      * @notify_populate:
      *
      * Notification that previously discarded memory is about to get populated.
      * Listeners are able to object. If any listener objects, already
      * successfully notified listeners are notified about a discard again.
      *
      * @rdl: the #RamDiscardListener getting notified
      * @section: the #MemoryRegionSection to get populated. The section
      *           is aligned within the memory region to the minimum granularity
      *           unless it would exceed the registered section.
      *
      * Returns 0 on success. If the notification is rejected by the listener,
      * an error is returned.
      */
     NotifyRamPopulate notify_populate;
 
     /*
      * @notify_discard:
      *
      * Notification that previously populated memory was discarded successfully
      * and listeners should drop all references to such memory and prevent
      * new population (e.g., unmap).
      *
      * @rdl: the #RamDiscardListener getting notified
      * @section: the #MemoryRegionSection to get populated. The section
      *           is aligned within the memory region to the minimum granularity
      *           unless it would exceed the registered section.
      */
     NotifyRamDiscard notify_discard;
 
     /*
      * @double_discard_supported:
      *
      * The listener suppors getting @notify_discard notifications that span
      * already discarded parts.
      */
     bool double_discard_supported;
 
     MemoryRegionSection *section;
     QLIST_ENTRY(RamDiscardListener) next;
 };
 
 static inline void ram_discard_listener_init(RamDiscardListener *rdl,
                                              NotifyRamPopulate populate_fn,
                                              NotifyRamDiscard discard_fn,
                                              bool double_discard_supported)
 {
     rdl->notify_populate = populate_fn;
     rdl->notify_discard = discard_fn;
     rdl->double_discard_supported = double_discard_supported;
 }
 
 typedef int (*ReplayRamPopulate)(MemoryRegionSection *section, void *opaque);
 typedef void (*ReplayRamDiscard)(MemoryRegionSection *section, void *opaque);
 
 /*
  * RamDiscardManagerClass:
  *
  * A #RamDiscardManager coordinates which parts of specific RAM #MemoryRegion
  * regions are currently populated to be used/accessed by the VM, notifying
  * after parts were discarded (freeing up memory) and before parts will be
  * populated (consuming memory), to be used/accessed by the VM.
  *
  * A #RamDiscardManager can only be set for a RAM #MemoryRegion while the
  * #MemoryRegion isn't mapped yet; it cannot change while the #MemoryRegion is
  * mapped.
  *
  * The #RamDiscardManager is intended to be used by technologies that are
  * incompatible with discarding of RAM (e.g., VFIO, which may pin all
  * memory inside a #MemoryRegion), and require proper coordination to only
  * map the currently populated parts, to hinder parts that are expected to
  * remain discarded from silently getting populated and consuming memory.
  * Technologies that support discarding of RAM don't have to bother and can
  * simply map the whole #MemoryRegion.
  *
  * An example #RamDiscardManager is virtio-mem, which logically (un)plugs
  * memory within an assigned RAM #MemoryRegion, coordinated with the VM.
  * Logically unplugging memory consists of discarding RAM. The VM agreed to not
  * access unplugged (discarded) memory - especially via DMA. virtio-mem will
  * properly coordinate with listeners before memory is plugged (populated),
  * and after memory is unplugged (discarded).
  *
  * Listeners are called in multiples of the minimum granularity (unless it
  * would exceed the registered range) and changes are aligned to the minimum
  * granularity within the #MemoryRegion. Listeners have to prepare for memory
  * becoming discarded in a different granularity than it was populated and the
  * other way around.
  */
 struct RamDiscardManagerClass {
     /* private */
     InterfaceClass parent_class;
 
     /* public */
 
     /**
      * @get_min_granularity:
      *
      * Get the minimum granularity in which listeners will get notified
      * about changes within the #MemoryRegion via the #RamDiscardManager.
      *
      * @rdm: the #RamDiscardManager
      * @mr: the #MemoryRegion
      *
      * Returns the minimum granularity.
      */
     uint64_t (*get_min_granularity)(const RamDiscardManager *rdm,
                                     const MemoryRegion *mr);
 
     /**
      * @is_populated:
      *
      * Check whether the given #MemoryRegionSection is completely populated
      * (i.e., no parts are currently discarded) via the #RamDiscardManager.
      * There are no alignment requirements.
      *
      * @rdm: the #RamDiscardManager
      * @section: the #MemoryRegionSection
      *
      * Returns whether the given range is completely populated.
      */
     bool (*is_populated)(const RamDiscardManager *rdm,
                          const MemoryRegionSection *section);
 
     /**
      * @replay_populated:
      *
      * Call the #ReplayRamPopulate callback for all populated parts within the
      * #MemoryRegionSection via the #RamDiscardManager.
      *
      * In case any call fails, no further calls are made.
      *
      * @rdm: the #RamDiscardManager
      * @section: the #MemoryRegionSection
      * @replay_fn: the #ReplayRamPopulate callback
      * @opaque: pointer to forward to the callback
      *
      * Returns 0 on success, or a negative error if any notification failed.
      */
     int (*replay_populated)(const RamDiscardManager *rdm,
                             MemoryRegionSection *section,
                             ReplayRamPopulate replay_fn, void *opaque);
 
     /**
      * @replay_discarded:
      *
      * Call the #ReplayRamDiscard callback for all discarded parts within the
      * #MemoryRegionSection via the #RamDiscardManager.
      *
      * @rdm: the #RamDiscardManager
      * @section: the #MemoryRegionSection
      * @replay_fn: the #ReplayRamDiscard callback
      * @opaque: pointer to forward to the callback
      */
     void (*replay_discarded)(const RamDiscardManager *rdm,
                              MemoryRegionSection *section,
                              ReplayRamDiscard replay_fn, void *opaque);
 
     /**
      * @register_listener:
      *
      * Register a #RamDiscardListener for the given #MemoryRegionSection and
      * immediately notify the #RamDiscardListener about all populated parts
      * within the #MemoryRegionSection via the #RamDiscardManager.
      *
      * In case any notification fails, no further notifications are triggered
      * and an error is logged.
      *
      * @rdm: the #RamDiscardManager
      * @rdl: the #RamDiscardListener
      * @section: the #MemoryRegionSection
      */
     void (*register_listener)(RamDiscardManager *rdm,
                               RamDiscardListener *rdl,
                               MemoryRegionSection *section);
 
     /**
      * @unregister_listener:
      *
      * Unregister a previously registered #RamDiscardListener via the
      * #RamDiscardManager after notifying the #RamDiscardListener about all
      * populated parts becoming unpopulated within the registered
      * #MemoryRegionSection.
      *
      * @rdm: the #RamDiscardManager
      * @rdl: the #RamDiscardListener
      */
     void (*unregister_listener)(RamDiscardManager *rdm,
                                 RamDiscardListener *rdl);
 };
 
 uint64_t ram_discard_manager_get_min_granularity(const RamDiscardManager *rdm,
                                                  const MemoryRegion *mr);
 
 bool ram_discard_manager_is_populated(const RamDiscardManager *rdm,
                                       const MemoryRegionSection *section);
 
 int ram_discard_manager_replay_populated(const RamDiscardManager *rdm,
                                          MemoryRegionSection *section,
                                          ReplayRamPopulate replay_fn,
                                          void *opaque);
 
 void ram_discard_manager_replay_discarded(const RamDiscardManager *rdm,
                                           MemoryRegionSection *section,
                                           ReplayRamDiscard replay_fn,
                                           void *opaque);
 
 void ram_discard_manager_register_listener(RamDiscardManager *rdm,
                                            RamDiscardListener *rdl,
                                            MemoryRegionSection *section);
 
 void ram_discard_manager_unregister_listener(RamDiscardManager *rdm,
                                              RamDiscardListener *rdl);
 
 bool memory_get_xlat_addr(IOMMUTLBEntry *iotlb, void **vaddr,
                           ram_addr_t *ram_addr, bool *read_only,
                           bool *mr_has_discard_manager);
 
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
 typedef struct MemoryRegionIoeventfd MemoryRegionIoeventfd;
 
 /** MemoryRegion:
  *
  * A struct representing a memory region.
  */
 struct MemoryRegion {
     Object parent_obj;
 
     /* private: */
 
     /* The following fields should fit in a cache line */
     bool romd_mode;
     bool ram;
     bool subpage;
     bool readonly; /* For RAM regions */
     bool nonvolatile;
     bool rom_device;
     bool flush_coalesced_mmio;
     uint8_t dirty_log_mask;
     bool is_iommu;
     RAMBlock *ram_block;
     Object *owner;
 
     const MemoryRegionOps *ops;
     void *opaque;
     MemoryRegion *container;
     int mapped_via_alias; /* Mapped via an alias, container might be NULL */
     Int128 size;
     hwaddr addr;
     void (*destructor)(MemoryRegion *mr);
     uint64_t align;
     bool terminates;
     bool ram_device;
     bool enabled;
     bool warning_printed; /* For reservations */
     uint8_t vga_logging_count;
     MemoryRegion *alias;
     hwaddr alias_offset;
     int32_t priority;
     QTAILQ_HEAD(, MemoryRegion) subregions;
     QTAILQ_ENTRY(MemoryRegion) subregions_link;
     QTAILQ_HEAD(, CoalescedMemoryRange) coalesced;
     const char *name;
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
     RamDiscardManager *rdm; /* Only for RAM */
 };
 
 struct IOMMUMemoryRegion {
     MemoryRegion parent_obj;
 
     QLIST_HEAD(, IOMMUNotifier) iommu_notify;
     IOMMUNotifierFlag iommu_notify_flags;
 };
 
 #define IOMMU_NOTIFIER_FOREACH(n, mr) \
     QLIST_FOREACH((n), &(mr)->iommu_notify, node)
 
 /**
  * struct MemoryListener: callbacks structure for updates to the physical memory map
  *
  * Allows a component to adjust to changes in the guest-visible memory map.
  * Use with memory_listener_register() and memory_listener_unregister().
  */
 struct MemoryListener {
     /**
      * @begin:
      *
      * Called at the beginning of an address space update transaction.
      * Followed by calls to #MemoryListener.region_add(),
      * #MemoryListener.region_del(), #MemoryListener.region_nop(),
      * #MemoryListener.log_start() and #MemoryListener.log_stop() in
      * increasing address order.
      *
      * @listener: The #MemoryListener.
      */
     void (*begin)(MemoryListener *listener);
 
     /**
      * @commit:
      *
      * Called at the end of an address space update transaction,
      * after the last call to #MemoryListener.region_add(),
      * #MemoryListener.region_del() or #MemoryListener.region_nop(),
      * #MemoryListener.log_start() and #MemoryListener.log_stop().
      *
      * @listener: The #MemoryListener.
      */
     void (*commit)(MemoryListener *listener);
 
     /**
      * @region_add:
      *
      * Called during an address space update transaction,
      * for a section of the address space that is new in this address space
      * space since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The new #MemoryRegionSection.
      */
     void (*region_add)(MemoryListener *listener, MemoryRegionSection *section);
 
     /**
      * @region_del:
      *
      * Called during an address space update transaction,
      * for a section of the address space that has disappeared in the address
      * space since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The old #MemoryRegionSection.
      */
     void (*region_del)(MemoryListener *listener, MemoryRegionSection *section);
 
     /**
      * @region_nop:
      *
      * Called during an address space update transaction,
      * for a section of the address space that is in the same place in the address
      * space as in the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The #MemoryRegionSection.
      */
     void (*region_nop)(MemoryListener *listener, MemoryRegionSection *section);
 
     /**
      * @log_start:
      *
      * Called during an address space update transaction, after
      * one of #MemoryListener.region_add(), #MemoryListener.region_del() or
      * #MemoryListener.region_nop(), if dirty memory logging clients have
      * become active since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The #MemoryRegionSection.
      * @old: A bitmap of dirty memory logging clients that were active in
      * the previous transaction.
      * @new: A bitmap of dirty memory logging clients that are active in
      * the current transaction.
      */
     void (*log_start)(MemoryListener *listener, MemoryRegionSection *section,
                       int old, int new);
 
     /**
      * @log_stop:
      *
      * Called during an address space update transaction, after
      * one of #MemoryListener.region_add(), #MemoryListener.region_del() or
      * #MemoryListener.region_nop() and possibly after
      * #MemoryListener.log_start(), if dirty memory logging clients have
      * become inactive since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The #MemoryRegionSection.
      * @old: A bitmap of dirty memory logging clients that were active in
      * the previous transaction.
      * @new: A bitmap of dirty memory logging clients that are active in
      * the current transaction.
      */
     void (*log_stop)(MemoryListener *listener, MemoryRegionSection *section,
                      int old, int new);
 
     /**
      * @log_sync:
      *
      * Called by memory_region_snapshot_and_clear_dirty() and
      * memory_global_dirty_log_sync(), before accessing QEMU's "official"
      * copy of the dirty memory bitmap for a #MemoryRegionSection.
      *
      * @listener: The #MemoryListener.
      * @section: The #MemoryRegionSection.
      */
     void (*log_sync)(MemoryListener *listener, MemoryRegionSection *section);
 
     /**
      * @log_sync_global:
      *
      * This is the global version of @log_sync when the listener does
      * not have a way to synchronize the log with finer granularity.
      * When the listener registers with @log_sync_global defined, then
      * its @log_sync must be NULL.  Vice versa.
      *
      * @listener: The #MemoryListener.
      */
     void (*log_sync_global)(MemoryListener *listener);
 
     /**
      * @log_clear:
      *
      * Called before reading the dirty memory bitmap for a
      * #MemoryRegionSection.
      *
      * @listener: The #MemoryListener.
      * @section: The #MemoryRegionSection.
      */
     void (*log_clear)(MemoryListener *listener, MemoryRegionSection *section);
 
     /**
      * @log_global_start:
      *
      * Called by memory_global_dirty_log_start(), which
      * enables the %DIRTY_LOG_MIGRATION client on all memory regions in
      * the address space.  #MemoryListener.log_global_start() is also
      * called when a #MemoryListener is added, if global dirty logging is
      * active at that time.
      *
      * @listener: The #MemoryListener.
      */
     void (*log_global_start)(MemoryListener *listener);
 
     /**
      * @log_global_stop:
      *
      * Called by memory_global_dirty_log_stop(), which
      * disables the %DIRTY_LOG_MIGRATION client on all memory regions in
      * the address space.
      *
      * @listener: The #MemoryListener.
      */
     void (*log_global_stop)(MemoryListener *listener);
 
     /**
      * @log_global_after_sync:
      *
      * Called after reading the dirty memory bitmap
      * for any #MemoryRegionSection.
      *
      * @listener: The #MemoryListener.
      */
     void (*log_global_after_sync)(MemoryListener *listener);
 
     /**
      * @eventfd_add:
      *
      * Called during an address space update transaction,
      * for a section of the address space that has had a new ioeventfd
      * registration since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The new #MemoryRegionSection.
      * @match_data: The @match_data parameter for the new ioeventfd.
      * @data: The @data parameter for the new ioeventfd.
      * @e: The #EventNotifier parameter for the new ioeventfd.
      */
     void (*eventfd_add)(MemoryListener *listener, MemoryRegionSection *section,
                         bool match_data, uint64_t data, EventNotifier *e);
 
     /**
      * @eventfd_del:
      *
      * Called during an address space update transaction,
      * for a section of the address space that has dropped an ioeventfd
      * registration since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The new #MemoryRegionSection.
      * @match_data: The @match_data parameter for the dropped ioeventfd.
      * @data: The @data parameter for the dropped ioeventfd.
      * @e: The #EventNotifier parameter for the dropped ioeventfd.
      */
     void (*eventfd_del)(MemoryListener *listener, MemoryRegionSection *section,
                         bool match_data, uint64_t data, EventNotifier *e);
 
     /**
      * @coalesced_io_add:
      *
      * Called during an address space update transaction,
      * for a section of the address space that has had a new coalesced
      * MMIO range registration since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The new #MemoryRegionSection.
      * @addr: The starting address for the coalesced MMIO range.
      * @len: The length of the coalesced MMIO range.
      */
     void (*coalesced_io_add)(MemoryListener *listener, MemoryRegionSection *section,
                                hwaddr addr, hwaddr len);
 
     /**
      * @coalesced_io_del:
      *
      * Called during an address space update transaction,
      * for a section of the address space that has dropped a coalesced
      * MMIO range since the last transaction.
      *
      * @listener: The #MemoryListener.
      * @section: The new #MemoryRegionSection.
      * @addr: The starting address for the coalesced MMIO range.
      * @len: The length of the coalesced MMIO range.
      */
     void (*coalesced_io_del)(MemoryListener *listener, MemoryRegionSection *section,
                                hwaddr addr, hwaddr len);
     /**
      * @priority:
      *
      * Govern the order in which memory listeners are invoked. Lower priorities
      * are invoked earlier for "add" or "start" callbacks, and later for "delete"
      * or "stop" callbacks.
      */
     unsigned priority;
 
     /**
      * @name:
      *
      * Name of the listener.  It can be used in contexts where we'd like to
      * identify one memory listener with the rest.
      */
     const char *name;
 
     /* private: */
     AddressSpace *address_space;
     QTAILQ_ENTRY(MemoryListener) link;
     QTAILQ_ENTRY(MemoryListener) link_as;
 };
 
 /**
  * struct AddressSpace: describes a mapping of addresses to #MemoryRegion objects
  */
 struct AddressSpace {
     /* private: */
     struct rcu_head rcu;
     char *name;
     MemoryRegion *root;
 
     /* Accessed via RCU.  */
     struct FlatView *current_map;
 
     int ioeventfd_nb;
     struct MemoryRegionIoeventfd *ioeventfds;
     QTAILQ_HEAD(, MemoryListener) listeners;
     QTAILQ_ENTRY(AddressSpace) address_spaces_link;
 };
 
 typedef struct AddressSpaceDispatch AddressSpaceDispatch;
 typedef struct FlatRange FlatRange;
 
 /* Flattened global view of current active memory hierarchy.  Kept in sorted
  * order.
  */
 struct FlatView {
     struct rcu_head rcu;
     unsigned ref;
     FlatRange *ranges;
     unsigned nr;
     unsigned nr_allocated;
     struct AddressSpaceDispatch *dispatch;
     MemoryRegion *root;
 };
 
 static inline FlatView *address_space_to_flatview(AddressSpace *as)
 {
     return qatomic_rcu_read(&as->current_map);
 }
 
 /**
  * typedef flatview_cb: callback for flatview_for_each_range()
  *
  * @start: start address of the range within the FlatView
  * @len: length of the range in bytes
  * @mr: MemoryRegion covering this range
  * @offset_in_region: offset of the first byte of the range within @mr
  * @opaque: data pointer passed to flatview_for_each_range()
  *
  * Returns: true to stop the iteration, false to keep going.
  */
 typedef bool (*flatview_cb)(Int128 start,
                             Int128 len,
                             const MemoryRegion *mr,
                             hwaddr offset_in_region,
                             void *opaque);
 
 /**
  * flatview_for_each_range: Iterate through a FlatView
  * @fv: the FlatView to iterate through
  * @cb: function to call for each range
  * @opaque: opaque data pointer to pass to @cb
  *
  * A FlatView is made up of a list of non-overlapping ranges, each of
  * which is a slice of a MemoryRegion. This function iterates through
  * each range in @fv, calling @cb. The callback function can terminate
  * iteration early by returning 'true'.
  */
 void flatview_for_each_range(FlatView *fv, flatview_cb cb, void *opaque);
 
 static inline bool MemoryRegionSection_eq(MemoryRegionSection *a,
                                           MemoryRegionSection *b)
 {
     return a->mr == b->mr &&
            a->fv == b->fv &&
            a->offset_within_region == b->offset_within_region &&
            a->offset_within_address_space == b->offset_within_address_space &&
            int128_eq(a->size, b->size) &&
            a->readonly == b->readonly &&
            a->nonvolatile == b->nonvolatile;
 }
 
 /**
  * memory_region_section_new_copy: Copy a memory region section
  *
  * Allocate memory for a new copy, copy the memory region section, and
  * properly take a reference on all relevant members.
  *
  * @s: the #MemoryRegionSection to copy
  */
 MemoryRegionSection *memory_region_section_new_copy(MemoryRegionSection *s);
 
 /**
  * memory_region_section_new_copy: Free a copied memory region section
  *
  * Free a copy of a memory section created via memory_region_section_new_copy().
  * properly dropping references on all relevant members.
  *
  * @s: the #MemoryRegionSection to copy
  */
 void memory_region_section_free_copy(MemoryRegionSection *s);
 
 /**
  * memory_region_init: Initialize a memory region
  *
  * The region typically acts as a container for other memory regions.  Use
  * memory_region_add_subregion() to add subregions.
  *
  * @mr: the #MemoryRegion to be initialized
  * @owner: the object that tracks the region's reference count
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region; any subregions beyond this size will be clipped
  */
 void memory_region_init(MemoryRegion *mr,
                         Object *owner,
                         const char *name,
                         uint64_t size);
 
 /**
  * memory_region_ref: Add 1 to a memory region's reference count
  *
  * Whenever memory regions are accessed outside the BQL, they need to be
  * preserved against hot-unplug.  MemoryRegions actually do not have their
  * own reference count; they piggyback on a QOM object, their "owner".
  * This function adds a reference to the owner.
  *
  * All MemoryRegions must have an owner if they can disappear, even if the
  * device they belong to operates exclusively under the BQL.  This is because
  * the region could be returned at any time by memory_region_find, and this
  * is usually under guest control.
  *
  * @mr: the #MemoryRegion
  */
 void memory_region_ref(MemoryRegion *mr);
 
 /**
  * memory_region_unref: Remove 1 to a memory region's reference count
  *
  * Whenever memory regions are accessed outside the BQL, they need to be
  * preserved against hot-unplug.  MemoryRegions actually do not have their
  * own reference count; they piggyback on a QOM object, their "owner".
  * This function removes a reference to the owner and possibly destroys it.
  *
  * @mr: the #MemoryRegion
  */
 void memory_region_unref(MemoryRegion *mr);
 
 /**
  * memory_region_init_io: Initialize an I/O memory region.
  *
  * Accesses into the region will cause the callbacks in @ops to be called.
  * if @size is nonzero, subregions will be clipped to @size.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @ops: a structure containing read and write callbacks to be used when
  *       I/O is performed on the region.
  * @opaque: passed to the read and write callbacks of the @ops structure.
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region.
  */
 void memory_region_init_io(MemoryRegion *mr,
                            Object *owner,
                            const MemoryRegionOps *ops,
                            void *opaque,
                            const char *name,
                            uint64_t size);
 
 /**
  * memory_region_init_ram_nomigrate:  Initialize RAM memory region.  Accesses
  *                                    into the region will modify memory
  *                                    directly.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  */
 void memory_region_init_ram_nomigrate(MemoryRegion *mr,
                                       Object *owner,
                                       const char *name,
                                       uint64_t size,
                                       Error **errp);
 
 /**
  * memory_region_init_ram_flags_nomigrate:  Initialize RAM memory region.
  *                                          Accesses into the region will
  *                                          modify memory directly.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_NORESERVE.
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  */
 void memory_region_init_ram_flags_nomigrate(MemoryRegion *mr,
                                             Object *owner,
                                             const char *name,
                                             uint64_t size,
                                             uint32_t ram_flags,
                                             Error **errp);
 
 /**
  * memory_region_init_resizeable_ram:  Initialize memory region with resizable
  *                                     RAM.  Accesses into the region will
  *                                     modify memory directly.  Only an initial
  *                                     portion of this RAM is actually used.
  *                                     Changing the size while migrating
  *                                     can result in the migration being
  *                                     canceled.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: used size of the region.
  * @max_size: max size of the region.
  * @resized: callback to notify owner about used size change.
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  */
 void memory_region_init_resizeable_ram(MemoryRegion *mr,
                                        Object *owner,
                                        const char *name,
                                        uint64_t size,
                                        uint64_t max_size,
                                        void (*resized)(const char*,
                                                        uint64_t length,
                                                        void *host),
                                        Error **errp);
 #ifdef CONFIG_POSIX
 
 /**
  * memory_region_init_ram_from_file:  Initialize RAM memory region with a
  *                                    mmap-ed backend.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @align: alignment of the region base address; if 0, the default alignment
  *         (getpagesize()) will be used.
  * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
  *             RAM_NORESERVE,
  * @path: the path in which to allocate the RAM.
  * @readonly: true to open @path for reading, false for read/write.
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  */
 void memory_region_init_ram_from_file(MemoryRegion *mr,
                                       Object *owner,
                                       const char *name,
                                       uint64_t size,
                                       uint64_t align,
                                       uint32_t ram_flags,
                                       const char *path,
                                       bool readonly,
                                       Error **errp);
 
 /**
  * memory_region_init_ram_from_fd:  Initialize RAM memory region with a
  *                                  mmap-ed backend.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: the name of the region.
  * @size: size of the region.
  * @ram_flags: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
  *             RAM_NORESERVE, RAM_PROTECTED.
  * @fd: the fd to mmap.
  * @offset: offset within the file referenced by fd
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  */
 void memory_region_init_ram_from_fd(MemoryRegion *mr,
                                     Object *owner,
                                     const char *name,
                                     uint64_t size,
                                     uint32_t ram_flags,
                                     int fd,
                                     ram_addr_t offset,
                                     Error **errp);
 #endif
 
 /**
  * memory_region_init_ram_ptr:  Initialize RAM memory region from a
  *                              user-provided pointer.  Accesses into the
  *                              region will modify memory directly.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @ptr: memory to be mapped; must contain at least @size bytes.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  */
 void memory_region_init_ram_ptr(MemoryRegion *mr,
                                 Object *owner,
                                 const char *name,
                                 uint64_t size,
                                 void *ptr);
 
 /**
  * memory_region_init_ram_device_ptr:  Initialize RAM device memory region from
  *                                     a user-provided pointer.
  *
  * A RAM device represents a mapping to a physical device, such as to a PCI
  * MMIO BAR of an vfio-pci assigned device.  The memory region may be mapped
  * into the VM address space and access to the region will modify memory
  * directly.  However, the memory region should not be included in a memory
  * dump (device may not be enabled/mapped at the time of the dump), and
  * operations incompatible with manipulating MMIO should be avoided.  Replaces
  * skip_dump flag.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: the name of the region.
  * @size: size of the region.
  * @ptr: memory to be mapped; must contain at least @size bytes.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM memory region to be migrated; that is the responsibility of the caller.
  * (For RAM device memory regions, migrating the contents rarely makes sense.)
  */
 void memory_region_init_ram_device_ptr(MemoryRegion *mr,
                                        Object *owner,
                                        const char *name,
                                        uint64_t size,
                                        void *ptr);
 
 /**
  * memory_region_init_alias: Initialize a memory region that aliases all or a
  *                           part of another memory region.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: used for debugging; not visible to the user or ABI
  * @orig: the region to be referenced; @mr will be equivalent to
  *        @orig between @offset and @offset + @size - 1.
  * @offset: start of the section in @orig to be referenced.
  * @size: size of the region.
  */
 void memory_region_init_alias(MemoryRegion *mr,
                               Object *owner,
                               const char *name,
                               MemoryRegion *orig,
                               hwaddr offset,
                               uint64_t size);
 
 /**
  * memory_region_init_rom_nomigrate: Initialize a ROM memory region.
  *
  * This has the same effect as calling memory_region_init_ram_nomigrate()
  * and then marking the resulting region read-only with
  * memory_region_set_readonly().
  *
  * Note that this function does not do anything to cause the data in the
  * RAM side of the memory region to be migrated; that is the responsibility
  * of the caller.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @errp: pointer to Error*, to store an error if it happens.
  */
 void memory_region_init_rom_nomigrate(MemoryRegion *mr,
                                       Object *owner,
                                       const char *name,
                                       uint64_t size,
                                       Error **errp);
 
 /**
  * memory_region_init_rom_device_nomigrate:  Initialize a ROM memory region.
  *                                 Writes are handled via callbacks.
  *
  * Note that this function does not do anything to cause the data in the
  * RAM side of the memory region to be migrated; that is the responsibility
  * of the caller.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @ops: callbacks for write access handling (must not be NULL).
  * @opaque: passed to the read and write callbacks of the @ops structure.
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @errp: pointer to Error*, to store an error if it happens.
  */
 void memory_region_init_rom_device_nomigrate(MemoryRegion *mr,
                                              Object *owner,
                                              const MemoryRegionOps *ops,
                                              void *opaque,
                                              const char *name,
                                              uint64_t size,
                                              Error **errp);
 
 /**
  * memory_region_init_iommu: Initialize a memory region of a custom type
  * that translates addresses
  *
  * An IOMMU region translates addresses and forwards accesses to a target
  * memory region.
  *
  * The IOMMU implementation must define a subclass of TYPE_IOMMU_MEMORY_REGION.
  * @_iommu_mr should be a pointer to enough memory for an instance of
  * that subclass, @instance_size is the size of that subclass, and
  * @mrtypename is its name. This function will initialize @_iommu_mr as an
  * instance of the subclass, and its methods will then be called to handle
  * accesses to the memory region. See the documentation of
  * #IOMMUMemoryRegionClass for further details.
  *
  * @_iommu_mr: the #IOMMUMemoryRegion to be initialized
  * @instance_size: the IOMMUMemoryRegion subclass instance size
  * @mrtypename: the type name of the #IOMMUMemoryRegion
  * @owner: the object that tracks the region's reference count
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region.
  */
 void memory_region_init_iommu(void *_iommu_mr,
                               size_t instance_size,
                               const char *mrtypename,
                               Object *owner,
                               const char *name,
                               uint64_t size);
 
 /**
  * memory_region_init_ram - Initialize RAM memory region.  Accesses into the
  *                          region will modify memory directly.
  *
  * @mr: the #MemoryRegion to be initialized
  * @owner: the object that tracks the region's reference count (must be
  *         TYPE_DEVICE or a subclass of TYPE_DEVICE, or NULL)
  * @name: name of the memory region
  * @size: size of the region in bytes
  * @errp: pointer to Error*, to store an error if it happens.
  *
  * This function allocates RAM for a board model or device, and
  * arranges for it to be migrated (by calling vmstate_register_ram()
  * if @owner is a DeviceState, or vmstate_register_ram_global() if
  * @owner is NULL).
  *
  * TODO: Currently we restrict @owner to being either NULL (for
  * global RAM regions with no owner) or devices, so that we can
  * give the RAM block a unique name for migration purposes.
  * We should lift this restriction and allow arbitrary Objects.
  * If you pass a non-NULL non-device @owner then we will assert.
  */
 void memory_region_init_ram(MemoryRegion *mr,
                             Object *owner,
                             const char *name,
                             uint64_t size,
                             Error **errp);
 
 /**
  * memory_region_init_rom: Initialize a ROM memory region.
  *
  * This has the same effect as calling memory_region_init_ram()
  * and then marking the resulting region read-only with
  * memory_region_set_readonly(). This includes arranging for the
  * contents to be migrated.
  *
  * TODO: Currently we restrict @owner to being either NULL (for
  * global RAM regions with no owner) or devices, so that we can
  * give the RAM block a unique name for migration purposes.
  * We should lift this restriction and allow arbitrary Objects.
  * If you pass a non-NULL non-device @owner then we will assert.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @errp: pointer to Error*, to store an error if it happens.
  */
 void memory_region_init_rom(MemoryRegion *mr,
                             Object *owner,
                             const char *name,
                             uint64_t size,
                             Error **errp);
 
 /**
  * memory_region_init_rom_device:  Initialize a ROM memory region.
  *                                 Writes are handled via callbacks.
  *
  * This function initializes a memory region backed by RAM for reads
  * and callbacks for writes, and arranges for the RAM backing to
  * be migrated (by calling vmstate_register_ram()
  * if @owner is a DeviceState, or vmstate_register_ram_global() if
  * @owner is NULL).
  *
  * TODO: Currently we restrict @owner to being either NULL (for
  * global RAM regions with no owner) or devices, so that we can
  * give the RAM block a unique name for migration purposes.
  * We should lift this restriction and allow arbitrary Objects.
  * If you pass a non-NULL non-device @owner then we will assert.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
  * @ops: callbacks for write access handling (must not be NULL).
  * @opaque: passed to the read and write callbacks of the @ops structure.
  * @name: Region name, becomes part of RAMBlock name used in migration stream
  *        must be unique within any device
  * @size: size of the region.
  * @errp: pointer to Error*, to store an error if it happens.
  */
 void memory_region_init_rom_device(MemoryRegion *mr,
                                    Object *owner,
                                    const MemoryRegionOps *ops,
                                    void *opaque,
                                    const char *name,
                                    uint64_t size,
                                    Error **errp);
 
 
 /**
  * memory_region_owner: get a memory region's owner.
  *
  * @mr: the memory region being queried.
  */
 Object *memory_region_owner(MemoryRegion *mr);
 
 /**
  * memory_region_size: get a memory region's size.
  *
  * @mr: the memory region being queried.
  */
 uint64_t memory_region_size(MemoryRegion *mr);
 
 /**
  * memory_region_is_ram: check whether a memory region is random access
  *
  * Returns %true if a memory region is random access.
  *
  * @mr: the memory region being queried
  */
 static inline bool memory_region_is_ram(MemoryRegion *mr)
 {
     return mr->ram;
 }
 
 /**
  * memory_region_is_ram_device: check whether a memory region is a ram device
  *
  * Returns %true if a memory region is a device backed ram region
  *
  * @mr: the memory region being queried
  */
 bool memory_region_is_ram_device(MemoryRegion *mr);
 
 /**
  * memory_region_is_romd: check whether a memory region is in ROMD mode
  *
  * Returns %true if a memory region is a ROM device and currently set to allow
  * direct reads.
  *
  * @mr: the memory region being queried
  */
 static inline bool memory_region_is_romd(MemoryRegion *mr)
 {
     return mr->rom_device && mr->romd_mode;
 }
 
 /**
  * memory_region_is_protected: check whether a memory region is protected
  *
  * Returns %true if a memory region is protected RAM and cannot be accessed
  * via standard mechanisms, e.g. DMA.
  *
  * @mr: the memory region being queried
  */
 bool memory_region_is_protected(MemoryRegion *mr);
 
 /**
  * memory_region_get_iommu: check whether a memory region is an iommu
  *
  * Returns pointer to IOMMUMemoryRegion if a memory region is an iommu,
  * otherwise NULL.
  *
  * @mr: the memory region being queried
  */
 static inline IOMMUMemoryRegion *memory_region_get_iommu(MemoryRegion *mr)
 {
     if (mr->alias) {
         return memory_region_get_iommu(mr->alias);
     }
     if (mr->is_iommu) {
         return (IOMMUMemoryRegion *) mr;
     }
     return NULL;
 }
 
 /**
  * memory_region_get_iommu_class_nocheck: returns iommu memory region class
  *   if an iommu or NULL if not
  *
  * Returns pointer to IOMMUMemoryRegionClass if a memory region is an iommu,
  * otherwise NULL. This is fast path avoiding QOM checking, use with caution.
  *
  * @iommu_mr: the memory region being queried
  */
 static inline IOMMUMemoryRegionClass *memory_region_get_iommu_class_nocheck(
         IOMMUMemoryRegion *iommu_mr)
 {
     return (IOMMUMemoryRegionClass *) (((Object *)iommu_mr)->class);
 }
 
 #define memory_region_is_iommu(mr) (memory_region_get_iommu(mr) != NULL)
 
 /**
  * memory_region_iommu_get_min_page_size: get minimum supported page size
  * for an iommu
  *
  * Returns minimum supported page size for an iommu.
  *
  * @iommu_mr: the memory region being queried
  */
 uint64_t memory_region_iommu_get_min_page_size(IOMMUMemoryRegion *iommu_mr);
 
 /**
  * memory_region_notify_iommu: notify a change in an IOMMU translation entry.
  *
  * Note: for any IOMMU implementation, an in-place mapping change
  * should be notified with an UNMAP followed by a MAP.
  *
  * @iommu_mr: the memory region that was changed
  * @iommu_idx: the IOMMU index for the translation table which has changed
  * @event: TLB event with the new entry in the IOMMU translation table.
  *         The entry replaces all old entries for the same virtual I/O address
  *         range.
  */
 void memory_region_notify_iommu(IOMMUMemoryRegion *iommu_mr,
                                 int iommu_idx,
                                 IOMMUTLBEvent event);
 
 /**
  * memory_region_notify_iommu_one: notify a change in an IOMMU translation
  *                           entry to a single notifier
  *
  * This works just like memory_region_notify_iommu(), but it only
  * notifies a specific notifier, not all of them.
  *
  * @notifier: the notifier to be notified
  * @event: TLB event with the new entry in the IOMMU translation table.
  *         The entry replaces all old entries for the same virtual I/O address
  *         range.
  */
 void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
                                     IOMMUTLBEvent *event);
 
 /**
  * memory_region_register_iommu_notifier: register a notifier for changes to
  * IOMMU translation entries.
  *
  * Returns 0 on success, or a negative errno otherwise. In particular,
  * -EINVAL indicates that at least one of the attributes of the notifier
  * is not supported (flag/range) by the IOMMU memory region. In case of error
  * the error object must be created.
  *
  * @mr: the memory region to observe
  * @n: the IOMMUNotifier to be added; the notify callback receives a
  *     pointer to an #IOMMUTLBEntry as the opaque value; the pointer
  *     ceases to be valid on exit from the notifier.
  * @errp: pointer to Error*, to store an error if it happens.
  */
 int memory_region_register_iommu_notifier(MemoryRegion *mr,
                                           IOMMUNotifier *n, Error **errp);
 
 /**
  * memory_region_iommu_replay: replay existing IOMMU translations to
  * a notifier with the minimum page granularity returned by
  * mr->iommu_ops->get_page_size().
  *
  * Note: this is not related to record-and-replay functionality.
  *
  * @iommu_mr: the memory region to observe
  * @n: the notifier to which to replay iommu mappings
  */
 void memory_region_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n);
 
 /**
  * memory_region_unregister_iommu_notifier: unregister a notifier for
  * changes to IOMMU translation entries.
  *
  * @mr: the memory region which was observed and for which notity_stopped()
  *      needs to be called
  * @n: the notifier to be removed.
  */
 void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
                                              IOMMUNotifier *n);
 
 /**
  * memory_region_iommu_get_attr: return an IOMMU attr if get_attr() is
  * defined on the IOMMU.
  *
  * Returns 0 on success, or a negative errno otherwise. In particular,
  * -EINVAL indicates that the IOMMU does not support the requested
  * attribute.
  *
  * @iommu_mr: the memory region
  * @attr: the requested attribute
  * @data: a pointer to the requested attribute data
  */
 int memory_region_iommu_get_attr(IOMMUMemoryRegion *iommu_mr,
                                  enum IOMMUMemoryRegionAttr attr,
                                  void *data);
 
 /**
  * memory_region_iommu_attrs_to_index: return the IOMMU index to
  * use for translations with the given memory transaction attributes.
  *
  * @iommu_mr: the memory region
  * @attrs: the memory transaction attributes
  */
 int memory_region_iommu_attrs_to_index(IOMMUMemoryRegion *iommu_mr,
                                        MemTxAttrs attrs);
 
 /**
  * memory_region_iommu_num_indexes: return the total number of IOMMU
  * indexes that this IOMMU supports.
  *
  * @iommu_mr: the memory region
  */
 int memory_region_iommu_num_indexes(IOMMUMemoryRegion *iommu_mr);
 
 /**
  * memory_region_iommu_set_page_size_mask: set the supported page
  * sizes for a given IOMMU memory region
  *
  * @iommu_mr: IOMMU memory region
  * @page_size_mask: supported page size mask
  * @errp: pointer to Error*, to store an error if it happens.
  */
 int memory_region_iommu_set_page_size_mask(IOMMUMemoryRegion *iommu_mr,
                                            uint64_t page_size_mask,
                                            Error **errp);
 
 /**
  * memory_region_name: get a memory region's name
  *
  * Returns the string that was used to initialize the memory region.
  *
  * @mr: the memory region being queried
  */
 const char *memory_region_name(const MemoryRegion *mr);
 
 /**
  * memory_region_is_logging: return whether a memory region is logging writes
  *
  * Returns %true if the memory region is logging writes for the given client
  *
  * @mr: the memory region being queried
  * @client: the client being queried
  */
 bool memory_region_is_logging(MemoryRegion *mr, uint8_t client);
 
 /**
  * memory_region_get_dirty_log_mask: return the clients for which a
  * memory region is logging writes.
  *
  * Returns a bitmap of clients, in which the DIRTY_MEMORY_* constants
  * are the bit indices.
  *
  * @mr: the memory region being queried
  */
 uint8_t memory_region_get_dirty_log_mask(MemoryRegion *mr);
 
 /**
  * memory_region_is_rom: check whether a memory region is ROM
  *
  * Returns %true if a memory region is read-only memory.
  *
  * @mr: the memory region being queried
  */
 static inline bool memory_region_is_rom(MemoryRegion *mr)
 {
     return mr->ram && mr->readonly;
 }
 
 /**
  * memory_region_is_nonvolatile: check whether a memory region is non-volatile
  *
  * Returns %true is a memory region is non-volatile memory.
  *
  * @mr: the memory region being queried
  */
 static inline bool memory_region_is_nonvolatile(MemoryRegion *mr)
 {
     return mr->nonvolatile;
 }
 
 /**
  * memory_region_get_fd: Get a file descriptor backing a RAM memory region.
  *
  * Returns a file descriptor backing a file-based RAM memory region,
  * or -1 if the region is not a file-based RAM memory region.
  *
  * @mr: the RAM or alias memory region being queried.
  */
 int memory_region_get_fd(MemoryRegion *mr);
 
 /**
  * memory_region_from_host: Convert a pointer into a RAM memory region
  * and an offset within it.
  *
  * Given a host pointer inside a RAM memory region (created with
  * memory_region_init_ram() or memory_region_init_ram_ptr()), return
  * the MemoryRegion and the offset within it.
  *
  * Use with care; by the time this function returns, the returned pointer is
  * not protected by RCU anymore.  If the caller is not within an RCU critical
  * section and does not hold the iothread lock, it must have other means of
  * protecting the pointer, such as a reference to the region that includes
  * the incoming ram_addr_t.
  *
  * @ptr: the host pointer to be converted
  * @offset: the offset within memory region
  */
 MemoryRegion *memory_region_from_host(void *ptr, ram_addr_t *offset);
 
 /**
  * memory_region_get_ram_ptr: Get a pointer into a RAM memory region.
  *
  * Returns a host pointer to a RAM memory region (created with
  * memory_region_init_ram() or memory_region_init_ram_ptr()).
  *
  * Use with care; by the time this function returns, the returned pointer is
  * not protected by RCU anymore.  If the caller is not within an RCU critical
  * section and does not hold the iothread lock, it must have other means of
  * protecting the pointer, such as a reference to the region that includes
  * the incoming ram_addr_t.
  *
  * @mr: the memory region being queried.
  */
 void *memory_region_get_ram_ptr(MemoryRegion *mr);
 
 /* memory_region_ram_resize: Resize a RAM region.
  *
  * Resizing RAM while migrating can result in the migration being canceled.
  * Care has to be taken if the guest might have already detected the memory.
  *
  * @mr: a memory region created with @memory_region_init_resizeable_ram.
  * @newsize: the new size the region
  * @errp: pointer to Error*, to store an error if it happens.
  */
 void memory_region_ram_resize(MemoryRegion *mr, ram_addr_t newsize,
                               Error **errp);
 
 /**
  * memory_region_msync: Synchronize selected address range of
  * a memory mapped region
  *
  * @mr: the memory region to be msync
  * @addr: the initial address of the range to be sync
  * @size: the size of the range to be sync
  */
 void memory_region_msync(MemoryRegion *mr, hwaddr addr, hwaddr size);
 
 /**
  * memory_region_writeback: Trigger cache writeback for
  * selected address range
  *
  * @mr: the memory region to be updated
  * @addr: the initial address of the range to be written back
  * @size: the size of the range to be written back
  */
 void memory_region_writeback(MemoryRegion *mr, hwaddr addr, hwaddr size);
 
 /**
  * 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).
  * Only meaningful for RAM regions.
  *
  * @mr: the memory region being updated.
  * @log: whether dirty logging is to be enabled or disabled.
  * @client: the user of the logging information; %DIRTY_MEMORY_VGA only.
  */
 void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client);
 
 /**
  * memory_region_set_dirty: Mark a range of bytes as dirty in a memory region.
  *
  * Marks a range of bytes as dirty, after it has been dirtied outside
  * guest code.
  *
  * @mr: the memory region being dirtied.
  * @addr: the address (relative to the start of the region) being dirtied.
  * @size: size of the range being dirtied.
  */
 void memory_region_set_dirty(MemoryRegion *mr, hwaddr addr,
                              hwaddr size);
 
 /**
  * memory_region_clear_dirty_bitmap - clear dirty bitmap for memory range
  *
  * This function is called when the caller wants to clear the remote
  * dirty bitmap of a memory range within the memory region.  This can
  * be used by e.g. KVM to manually clear dirty log when
  * KVM_CAP_MANUAL_DIRTY_LOG_PROTECT is declared support by the host
  * kernel.
  *
  * @mr:     the memory region to clear the dirty log upon
  * @start:  start address offset within the memory region
  * @len:    length of the memory region to clear dirty bitmap
  */
 void memory_region_clear_dirty_bitmap(MemoryRegion *mr, hwaddr start,
                                       hwaddr len);
 
 /**
  * memory_region_snapshot_and_clear_dirty: Get a snapshot of the dirty
  *                                         bitmap and clear it.
  *
  * Creates a snapshot of the dirty bitmap, clears the dirty bitmap and
  * returns the snapshot.  The snapshot can then be used to query dirty
  * status, using memory_region_snapshot_get_dirty.  Snapshotting allows
  * querying the same page multiple times, which is especially useful for
  * display updates where the scanlines often are not page aligned.
  *
  * The dirty bitmap region which gets copied into the snapshot (and
  * cleared afterwards) can be larger than requested.  The boundaries
  * are rounded up/down so complete bitmap longs (covering 64 pages on
  * 64bit hosts) can be copied over into the bitmap snapshot.  Which
  * isn't a problem for display updates as the extra pages are outside
  * the visible area, and in case the visible area changes a full
  * display redraw is due anyway.  Should other use cases for this
  * function emerge we might have to revisit this implementation
  * detail.
  *
  * Use g_free to release DirtyBitmapSnapshot.
  *
  * @mr: the memory region being queried.
  * @addr: the address (relative to the start of the region) being queried.
  * @size: the size of the range being queried.
  * @client: the user of the logging information; typically %DIRTY_MEMORY_VGA.
  */
 DirtyBitmapSnapshot *memory_region_snapshot_and_clear_dirty(MemoryRegion *mr,
                                                             hwaddr addr,
                                                             hwaddr size,
                                                             unsigned client);
 
 /**
  * memory_region_snapshot_get_dirty: Check whether a range of bytes is dirty
  *                                   in the specified dirty bitmap snapshot.
  *
  * @mr: the memory region being queried.
  * @snap: the dirty bitmap snapshot
  * @addr: the address (relative to the start of the region) being queried.
  * @size: the size of the range being queried.
  */
 bool memory_region_snapshot_get_dirty(MemoryRegion *mr,
                                       DirtyBitmapSnapshot *snap,
                                       hwaddr addr, hwaddr size);
 
 /**
  * memory_region_reset_dirty: Mark a range of pages as clean, for a specified
  *                            client.
  *
  * Marks a range of pages as no longer dirty.
  *
  * @mr: the region being updated.
  * @addr: the start of the subrange being cleaned.
  * @size: the size of the subrange being cleaned.
  * @client: the user of the logging information; %DIRTY_MEMORY_MIGRATION or
  *          %DIRTY_MEMORY_VGA.
  */
 void memory_region_reset_dirty(MemoryRegion *mr, hwaddr addr,
                                hwaddr size, unsigned client);
 
 /**
  * memory_region_flush_rom_device: Mark a range of pages dirty and invalidate
  *                                 TBs (for self-modifying code).
  *
  * The MemoryRegionOps->write() callback of a ROM device must use this function
  * to mark byte ranges that have been modified internally, such as by directly
  * accessing the memory returned by memory_region_get_ram_ptr().
  *
  * This function marks the range dirty and invalidates TBs so that TCG can
  * detect self-modifying code.
  *
  * @mr: the region being flushed.
  * @addr: the start, relative to the start of the region, of the range being
  *        flushed.
  * @size: the size, in bytes, of the range being flushed.
  */
 void memory_region_flush_rom_device(MemoryRegion *mr, hwaddr addr, hwaddr size);
 
 /**
  * memory_region_set_readonly: Turn a memory region read-only (or read-write)
  *
  * Allows a memory region to be marked as read-only (turning it into a ROM).
  * only useful on RAM regions.
  *
  * @mr: the region being updated.
  * @readonly: whether rhe region is to be ROM or RAM.
  */
 void memory_region_set_readonly(MemoryRegion *mr, bool readonly);
 
 /**
  * memory_region_set_nonvolatile: Turn a memory region non-volatile
  *
  * Allows a memory region to be marked as non-volatile.
  * only useful on RAM regions.
  *
  * @mr: the region being updated.
  * @nonvolatile: whether rhe region is to be non-volatile.
  */
 void memory_region_set_nonvolatile(MemoryRegion *mr, bool nonvolatile);
 
 /**
  * memory_region_rom_device_set_romd: enable/disable ROMD mode
  *
  * Allows a ROM device (initialized with memory_region_init_rom_device() to
  * set to ROMD mode (default) or MMIO mode.  When it is in ROMD mode, the
  * device is mapped to guest memory and satisfies read access directly.
  * When in MMIO mode, reads are forwarded to the #MemoryRegion.read function.
  * Writes are always handled by the #MemoryRegion.write function.
  *
  * @mr: the memory region to be updated
  * @romd_mode: %true to put the region into ROMD mode
  */
 void memory_region_rom_device_set_romd(MemoryRegion *mr, bool romd_mode);
 
 /**
  * memory_region_set_coalescing: Enable memory coalescing for the region.
  *
  * Enabled writes to a region to be queued for later processing. MMIO ->write
  * callbacks may be delayed until a non-coalesced MMIO is issued.
  * Only useful for IO regions.  Roughly similar to write-combining hardware.
  *
  * @mr: the memory region to be write coalesced
  */
 void memory_region_set_coalescing(MemoryRegion *mr);
 
 /**
  * memory_region_add_coalescing: Enable memory coalescing for a sub-range of
  *                               a region.
  *
  * Like memory_region_set_coalescing(), but works on a sub-range of a region.
  * Multiple calls can be issued coalesced disjoint ranges.
  *
  * @mr: the memory region to be updated.
  * @offset: the start of the range within the region to be coalesced.
  * @size: the size of the subrange to be coalesced.
  */
 void memory_region_add_coalescing(MemoryRegion *mr,
                                   hwaddr offset,
                                   uint64_t size);
 
 /**
  * memory_region_clear_coalescing: Disable MMIO coalescing for the region.
  *
  * Disables any coalescing caused by memory_region_set_coalescing() or
  * memory_region_add_coalescing().  Roughly equivalent to uncacheble memory
  * hardware.
  *
  * @mr: the memory region to be updated.
  */
 void memory_region_clear_coalescing(MemoryRegion *mr);
 
 /**
  * memory_region_set_flush_coalesced: Enforce memory coalescing flush before
  *                                    accesses.
  *
  * Ensure that pending coalesced MMIO request are flushed before the memory
  * region is accessed. This property is automatically enabled for all regions
  * passed to memory_region_set_coalescing() and memory_region_add_coalescing().
  *
  * @mr: the memory region to be updated.
  */
 void memory_region_set_flush_coalesced(MemoryRegion *mr);
 
 /**
  * memory_region_clear_flush_coalesced: Disable memory coalescing flush before
  *                                      accesses.
  *
  * Clear the automatic coalesced MMIO flushing enabled via
  * memory_region_set_flush_coalesced. Note that this service has no effect on
  * memory regions that have MMIO coalescing enabled for themselves. For them,
  * automatic flushing will stop once coalescing is disabled.
  *
  * @mr: the memory region to be updated.
  */
 void memory_region_clear_flush_coalesced(MemoryRegion *mr);
 
 /**
  * memory_region_add_eventfd: Request an eventfd to be triggered when a word
  *                            is written to a location.
  *
  * Marks a word in an IO region (initialized with memory_region_init_io())
  * as a trigger for an eventfd event.  The I/O callback will not be called.
  * The caller must be prepared to handle failure (that is, take the required
  * action if the callback _is_ called).
  *
  * @mr: the memory region being updated.
  * @addr: the address within @mr that is to be monitored
  * @size: the size of the access to trigger the eventfd
  * @match_data: whether to match against @data, instead of just @addr
  * @data: the data to match against the guest write
  * @e: event notifier to be triggered when @addr, @size, and @data all match.
  **/
 void memory_region_add_eventfd(MemoryRegion *mr,
                                hwaddr addr,
                                unsigned size,
                                bool match_data,
                                uint64_t data,
                                EventNotifier *e);
 
 /**
  * memory_region_del_eventfd: Cancel an eventfd.
  *
  * Cancels an eventfd trigger requested by a previous
  * memory_region_add_eventfd() call.
  *
  * @mr: the memory region being updated.
  * @addr: the address within @mr that is to be monitored
  * @size: the size of the access to trigger the eventfd
  * @match_data: whether to match against @data, instead of just @addr
  * @data: the data to match against the guest write
  * @e: event notifier to be triggered when @addr, @size, and @data all match.
  */
 void memory_region_del_eventfd(MemoryRegion *mr,
                                hwaddr addr,
                                unsigned size,
                                bool match_data,
                                uint64_t data,
                                EventNotifier *e);
 
 /**
  * memory_region_add_subregion: Add a subregion to a container.
  *
  * Adds a subregion at @offset.  The subregion may not overlap with other
  * subregions (except for those explicitly marked as overlapping).  A region
  * may only be added once as a subregion (unless removed with
  * memory_region_del_subregion()); use memory_region_init_alias() if you
  * want a region to be a subregion in multiple locations.
  *
  * @mr: the region to contain the new subregion; must be a container
  *      initialized with memory_region_init().
  * @offset: the offset relative to @mr where @subregion is added.
  * @subregion: the subregion to be added.
  */
 void memory_region_add_subregion(MemoryRegion *mr,
                                  hwaddr offset,
                                  MemoryRegion *subregion);
 /**
  * memory_region_add_subregion_overlap: Add a subregion to a container
  *                                      with overlap.
  *
  * Adds a subregion at @offset.  The subregion may overlap with other
  * subregions.  Conflicts are resolved by having a higher @priority hide a
  * lower @priority. Subregions without priority are taken as @priority 0.
  * A region may only be added once as a subregion (unless removed with
  * memory_region_del_subregion()); use memory_region_init_alias() if you
  * want a region to be a subregion in multiple locations.
  *
  * @mr: the region to contain the new subregion; must be a container
  *      initialized with memory_region_init().
  * @offset: the offset relative to @mr where @subregion is added.
  * @subregion: the subregion to be added.
  * @priority: used for resolving overlaps; highest priority wins.
  */
 void memory_region_add_subregion_overlap(MemoryRegion *mr,
                                          hwaddr offset,
                                          MemoryRegion *subregion,
                                          int priority);
 
 /**
  * memory_region_get_ram_addr: Get the ram address associated with a memory
  *                             region
  *
  * @mr: the region to be queried
  */
 ram_addr_t memory_region_get_ram_addr(MemoryRegion *mr);
 
 uint64_t memory_region_get_alignment(const MemoryRegion *mr);
 /**
  * memory_region_del_subregion: Remove a subregion.
  *
  * Removes a subregion from its container.
  *
  * @mr: the container to be updated.
  * @subregion: the region being removed; must be a current subregion of @mr.
  */
 void memory_region_del_subregion(MemoryRegion *mr,
                                  MemoryRegion *subregion);
 
 /*
  * memory_region_set_enabled: dynamically enable or disable a region
  *
  * Enables or disables a memory region.  A disabled memory region
  * ignores all accesses to itself and its subregions.  It does not
  * obscure sibling subregions with lower priority - it simply behaves as
  * if it was removed from the hierarchy.
  *
  * Regions default to being enabled.
  *
  * @mr: the region to be updated
  * @enabled: whether to enable or disable the region
  */
 void memory_region_set_enabled(MemoryRegion *mr, bool enabled);
 
 /*
  * memory_region_set_address: dynamically update the address of a region
  *
  * Dynamically updates the address of a region, relative to its container.
  * May be used on regions are currently part of a memory hierarchy.
  *
  * @mr: the region to be updated
  * @addr: new address, relative to container region
  */
 void memory_region_set_address(MemoryRegion *mr, hwaddr addr);
 
 /*
  * memory_region_set_size: dynamically update the size of a region.
  *
  * Dynamically updates the size of a region.
  *
  * @mr: the region to be updated
  * @size: used size of the region.
  */
 void memory_region_set_size(MemoryRegion *mr, uint64_t size);
 
 /*
  * memory_region_set_alias_offset: dynamically update a memory alias's offset
  *
  * Dynamically updates the offset into the target region that an alias points
  * to, as if the fourth argument to memory_region_init_alias() has changed.
  *
  * @mr: the #MemoryRegion to be updated; should be an alias.
  * @offset: the new offset into the target memory region
  */
 void memory_region_set_alias_offset(MemoryRegion *mr,
                                     hwaddr offset);
 
 /**
  * memory_region_present: checks if an address relative to a @container
  * translates into #MemoryRegion within @container
  *
  * Answer whether a #MemoryRegion within @container covers the address
  * @addr.
  *
  * @container: a #MemoryRegion within which @addr is a relative address
  * @addr: the area within @container to be searched
  */
 bool memory_region_present(MemoryRegion *container, hwaddr addr);
 
 /**
  * memory_region_is_mapped: returns true if #MemoryRegion is mapped
  * into another memory region, which does not necessarily imply that it is
  * mapped into an address space.
  *
  * @mr: a #MemoryRegion which should be checked if it's mapped
  */
 bool memory_region_is_mapped(MemoryRegion *mr);
 
 /**
  * memory_region_get_ram_discard_manager: get the #RamDiscardManager for a
  * #MemoryRegion
  *
  * The #RamDiscardManager cannot change while a memory region is mapped.
  *
  * @mr: the #MemoryRegion
  */
 RamDiscardManager *memory_region_get_ram_discard_manager(MemoryRegion *mr);
 
 /**
  * memory_region_has_ram_discard_manager: check whether a #MemoryRegion has a
  * #RamDiscardManager assigned
  *
  * @mr: the #MemoryRegion
  */
 static inline bool memory_region_has_ram_discard_manager(MemoryRegion *mr)
 {
     return !!memory_region_get_ram_discard_manager(mr);
 }
 
 /**
  * memory_region_set_ram_discard_manager: set the #RamDiscardManager for a
  * #MemoryRegion
  *
  * This function must not be called for a mapped #MemoryRegion, a #MemoryRegion
  * that does not cover RAM, or a #MemoryRegion that already has a
  * #RamDiscardManager assigned.
  *
  * @mr: the #MemoryRegion
  * @rdm: #RamDiscardManager to set
  */
 void memory_region_set_ram_discard_manager(MemoryRegion *mr,
                                            RamDiscardManager *rdm);
 
 /**
  * memory_region_find: translate an address/size relative to a
  * MemoryRegion into a #MemoryRegionSection.
  *
  * Locates the first #MemoryRegion within @mr that overlaps the range
  * given by @addr and @size.
  *
  * Returns a #MemoryRegionSection that describes a contiguous overlap.
  * It will have the following characteristics:
  * - @size = 0 iff no overlap was found
  * - @mr is non-%NULL iff an overlap was found
  *
  * Remember that in the return value the @offset_within_region is
  * relative to the returned region (in the .@mr field), not to the
  * @mr argument.
  *
  * Similarly, the .@offset_within_address_space is relative to the
  * address space that contains both regions, the passed and the
  * returned one.  However, in the special case where the @mr argument
  * has no container (and thus is the root of the address space), the
  * following will hold:
  * - @offset_within_address_space >= @addr
  * - @offset_within_address_space + .@size <= @addr + @size
  *
  * @mr: a MemoryRegion within which @addr is a relative address
  * @addr: start of the area within @as to be searched
  * @size: size of the area to be searched
  */
 MemoryRegionSection memory_region_find(MemoryRegion *mr,
                                        hwaddr addr, uint64_t size);
 
 /**
  * memory_global_dirty_log_sync: synchronize the dirty log for all memory
  *
  * Synchronizes the dirty page log for all address spaces.
  */
 void memory_global_dirty_log_sync(void);
 
 /**
  * memory_global_dirty_log_sync: synchronize the dirty log for all memory
  *
  * Synchronizes the vCPUs with a thread that is reading the dirty bitmap.
  * This function must be called after the dirty log bitmap is cleared, and
  * before dirty guest memory pages are read.  If you are using
  * #DirtyBitmapSnapshot, memory_region_snapshot_and_clear_dirty() takes
  * care of doing this.
  */
 void memory_global_after_dirty_log_sync(void);
 
 /**
  * memory_region_transaction_begin: Start a transaction.
  *
  * During a transaction, changes will be accumulated and made visible
  * only when the transaction ends (is committed).
  */
 void memory_region_transaction_begin(void);
 
 /**
  * memory_region_transaction_commit: Commit a transaction and make changes
  *                                   visible to the guest.
  */
 void memory_region_transaction_commit(void);
 
 /**
  * memory_listener_register: register callbacks to be called when memory
  *                           sections are mapped or unmapped into an address
  *                           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, AddressSpace *filter);
 
 /**
  * memory_listener_unregister: undo the effect of memory_listener_register()
  *
  * @listener: an object containing the callbacks to be removed
  */
 void memory_listener_unregister(MemoryListener *listener);
 
 /**
  * memory_global_dirty_log_start: begin dirty logging for all regions
  *
  * @flags: purpose of starting dirty log, migration or dirty rate
  */
 void memory_global_dirty_log_start(unsigned int flags);
 
 /**
  * memory_global_dirty_log_stop: end dirty logging for all regions
  *
  * @flags: purpose of stopping dirty log, migration or dirty rate
  */
 void memory_global_dirty_log_stop(unsigned int flags);
 
 void mtree_info(bool flatview, bool dispatch_tree, bool owner, bool disabled);
 
 /**
  * memory_region_dispatch_read: perform a read directly to the specified
  * MemoryRegion.
  *
  * @mr: #MemoryRegion to access
  * @addr: address within that region
  * @pval: pointer to uint64_t which the data is written to
  * @op: size, sign, and endianness of the memory operation
  * @attrs: memory transaction attributes to use for the access
  */
 MemTxResult memory_region_dispatch_read(MemoryRegion *mr,
                                         hwaddr addr,
                                         uint64_t *pval,
                                         MemOp op,
                                         MemTxAttrs attrs);
 /**
  * memory_region_dispatch_write: perform a write directly to the specified
  * MemoryRegion.
  *
  * @mr: #MemoryRegion to access
  * @addr: address within that region
  * @data: data to write
  * @op: size, sign, and endianness of the memory operation
  * @attrs: memory transaction attributes to use for the access
  */
 MemTxResult memory_region_dispatch_write(MemoryRegion *mr,
                                          hwaddr addr,
                                          uint64_t data,
                                          MemOp op,
                                          MemTxAttrs attrs);
 
 /**
  * address_space_init: initializes an address space
  *
  * @as: an uninitialized #AddressSpace
  * @root: a #MemoryRegion that routes addresses for the address space
  * @name: an address space name.  The name is only used for debugging
  *        output.
  */
 void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name);
 
 /**
  * address_space_destroy: destroy an address space
  *
  * Releases all resources associated with an address space.  After an address space
  * is destroyed, its root memory region (given by address_space_init()) may be destroyed
  * as well.
  *
  * @as: address space to be destroyed
  */
 void address_space_destroy(AddressSpace *as);
 
 /**
  * address_space_remove_listeners: unregister all listeners of an address space
  *
  * Removes all callbacks previously registered with memory_listener_register()
  * for @as.
  *
  * @as: an initialized #AddressSpace
  */
 void address_space_remove_listeners(AddressSpace *as);
 
 /**
  * address_space_rw: read from or write to an address space.
  *
  * Return a MemTxResult indicating whether the operation succeeded
  * or failed (eg unassigned memory, device rejected the transaction,
  * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  * @len: the number of bytes to read or write
  * @is_write: indicates the transfer direction
  */
 MemTxResult address_space_rw(AddressSpace *as, hwaddr addr,
                              MemTxAttrs attrs, void *buf,
                              hwaddr len, bool is_write);
 
 /**
  * address_space_write: write to address space.
  *
  * Return a MemTxResult indicating whether the operation succeeded
  * or failed (eg unassigned memory, device rejected the transaction,
  * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  * @len: the number of bytes to write
  */
 MemTxResult address_space_write(AddressSpace *as, hwaddr addr,
                                 MemTxAttrs attrs,
                                 const void *buf, hwaddr len);
 
 /**
  * address_space_write_rom: write to address space, including ROM.
  *
  * This function writes to the specified address space, but will
  * write data to both ROM and RAM. This is used for non-guest
  * writes like writes from the gdb debug stub or initial loading
  * of ROM contents.
  *
  * Note that portions of the write which attempt to write data to
  * a device will be silently ignored -- only real RAM and ROM will
  * be written to.
  *
  * Return a MemTxResult indicating whether the operation succeeded
  * or failed (eg unassigned memory, device rejected the transaction,
  * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  * @len: the number of bytes to write
  */
 MemTxResult address_space_write_rom(AddressSpace *as, hwaddr addr,
                                     MemTxAttrs attrs,
                                     const void *buf, hwaddr len);
 
 /* address_space_ld*: load from an address space
  * address_space_st*: store to an address space
  *
  * These functions perform a load or store of the byte, word,
  * longword or quad to the specified address within the AddressSpace.
  * The _le suffixed functions treat the data as little endian;
  * _be indicates big endian; no suffix indicates "same endianness
  * as guest CPU".
  *
  * The "guest CPU endianness" accessors are deprecated for use outside
  * target-* code; devices should be CPU-agnostic and use either the LE
  * or the BE accessors.
  *
  * @as #AddressSpace to be accessed
  * @addr: address within that address space
  * @val: data value, for stores
  * @attrs: memory transaction attributes
  * @result: location to write the success/failure of the transaction;
  *   if NULL, this information is discarded
  */
 
 #define SUFFIX
 #define ARG1         as
 #define ARG1_DECL    AddressSpace *as
 #include "exec/memory_ldst.h.inc"
 
 #define SUFFIX
 #define ARG1         as
 #define ARG1_DECL    AddressSpace *as
 #include "exec/memory_ldst_phys.h.inc"
 
 struct MemoryRegionCache {
     void *ptr;
     hwaddr xlat;
     hwaddr len;
     FlatView *fv;
     MemoryRegionSection mrs;
     bool is_write;
 };
 
 #define MEMORY_REGION_CACHE_INVALID ((MemoryRegionCache) { .mrs.mr = NULL })
 
 
 /* address_space_ld*_cached: load from a cached #MemoryRegion
  * address_space_st*_cached: store into a cached #MemoryRegion
  *
  * These functions perform a load or store of the byte, word,
  * longword or quad to the specified address.  The address is
  * a physical address in the AddressSpace, but it must lie within
  * a #MemoryRegion that was mapped with address_space_cache_init.
  *
  * The _le suffixed functions treat the data as little endian;
  * _be indicates big endian; no suffix indicates "same endianness
  * as guest CPU".
  *
  * The "guest CPU endianness" accessors are deprecated for use outside
  * target-* code; devices should be CPU-agnostic and use either the LE
  * or the BE accessors.
  *
  * @cache: previously initialized #MemoryRegionCache to be accessed
  * @addr: address within the address space
  * @val: data value, for stores
  * @attrs: memory transaction attributes
  * @result: location to write the success/failure of the transaction;
  *   if NULL, this information is discarded
  */
 
 #define SUFFIX       _cached_slow
 #define ARG1         cache
 #define ARG1_DECL    MemoryRegionCache *cache
 #include "exec/memory_ldst.h.inc"
 
 /* Inline fast path for direct RAM access.  */
 static inline uint8_t address_space_ldub_cached(MemoryRegionCache *cache,
     hwaddr addr, MemTxAttrs attrs, MemTxResult *result)
 {
     assert(addr < cache->len);
     if (likely(cache->ptr)) {
         return ldub_p(cache->ptr + addr);
     } else {
         return address_space_ldub_cached_slow(cache, addr, attrs, result);
     }
 }
 
 static inline void address_space_stb_cached(MemoryRegionCache *cache,
     hwaddr addr, uint8_t val, MemTxAttrs attrs, MemTxResult *result)
 {
     assert(addr < cache->len);
     if (likely(cache->ptr)) {
         stb_p(cache->ptr + addr, val);
     } else {
         address_space_stb_cached_slow(cache, addr, val, attrs, result);
     }
 }
 
 #define ENDIANNESS   _le
 #include "exec/memory_ldst_cached.h.inc"
 
 #define ENDIANNESS   _be
 #include "exec/memory_ldst_cached.h.inc"
 
 #define SUFFIX       _cached
 #define ARG1         cache
 #define ARG1_DECL    MemoryRegionCache *cache
 #include "exec/memory_ldst_phys.h.inc"
 
 /* address_space_cache_init: prepare for repeated access to a physical
  * memory region
  *
  * @cache: #MemoryRegionCache to be filled
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @len: length of buffer
  * @is_write: indicates the transfer direction
  *
  * Will only work with RAM, and may map a subset of the requested range by
  * returning a value that is less than @len.  On failure, return a negative
  * errno value.
  *
  * Because it only works with RAM, this function can be used for
  * read-modify-write operations.  In this case, is_write should be %true.
  *
  * Note that addresses passed to the address_space_*_cached functions
  * are relative to @addr.
  */
 int64_t address_space_cache_init(MemoryRegionCache *cache,
                                  AddressSpace *as,
                                  hwaddr addr,
                                  hwaddr len,
                                  bool is_write);
 
 /**
  * address_space_cache_invalidate: complete a write to a #MemoryRegionCache
  *
  * @cache: The #MemoryRegionCache to operate on.
  * @addr: The first physical address that was written, relative to the
  * address that was passed to @address_space_cache_init.
  * @access_len: The number of bytes that were written starting at @addr.
  */
 void address_space_cache_invalidate(MemoryRegionCache *cache,
                                     hwaddr addr,
                                     hwaddr access_len);
 
 /**
  * address_space_cache_destroy: free a #MemoryRegionCache
  *
  * @cache: The #MemoryRegionCache whose memory should be released.
  */
 void address_space_cache_destroy(MemoryRegionCache *cache);
 
 /* address_space_get_iotlb_entry: translate an address into an IOTLB
  * entry. Should be called from an RCU critical section.
  */
 IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr,
                                             bool is_write, MemTxAttrs attrs);
 
 /* address_space_translate: translate an address range into an address space
  * into a MemoryRegion and an address range into that section.  Should be
  * called from an RCU critical section, to avoid that the last reference
  * to the returned region disappears after address_space_translate returns.
  *
  * @fv: #FlatView to be accessed
  * @addr: address within that address space
  * @xlat: pointer to address within the returned memory region section's
  * #MemoryRegion.
  * @len: pointer to length
  * @is_write: indicates the transfer direction
  * @attrs: memory attributes
  */
 MemoryRegion *flatview_translate(FlatView *fv,
                                  hwaddr addr, hwaddr *xlat,
                                  hwaddr *len, bool is_write,
                                  MemTxAttrs attrs);
 
 static inline MemoryRegion *address_space_translate(AddressSpace *as,
                                                     hwaddr addr, hwaddr *xlat,
                                                     hwaddr *len, bool is_write,
                                                     MemTxAttrs attrs)
 {
     return flatview_translate(address_space_to_flatview(as),
                               addr, xlat, len, is_write, attrs);
 }
 
 /* address_space_access_valid: check for validity of accessing an address
  * space range
  *
  * Check whether memory is assigned to the given address space range, and
  * access is permitted by any IOMMU regions that are active for the address
  * space.
  *
  * For now, addr and len should be aligned to a page size.  This limitation
  * will be lifted in the future.
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @len: length of the area to be checked
  * @is_write: indicates the transfer direction
  * @attrs: memory attributes
  */
 bool address_space_access_valid(AddressSpace *as, hwaddr addr, hwaddr len,
                                 bool is_write, MemTxAttrs attrs);
 
 /* 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 and set *@plen to zero(0), 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
  * @attrs: memory attributes
  */
 void *address_space_map(AddressSpace *as, hwaddr addr,
                         hwaddr *plen, bool is_write, MemTxAttrs attrs);
 
 /* 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
  * @buffer: host pointer as returned by address_space_map()
  * @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, hwaddr len,
                          bool is_write, hwaddr access_len);
 
 
 /* Internal functions, part of the implementation of address_space_read.  */
 MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr,
                                     MemTxAttrs attrs, void *buf, hwaddr len);
 MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr,
                                    MemTxAttrs attrs, void *buf,
                                    hwaddr len, hwaddr addr1, hwaddr l,
                                    MemoryRegion *mr);
 void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr);
 
 /* Internal functions, part of the implementation of address_space_read_cached
  * and address_space_write_cached.  */
 MemTxResult address_space_read_cached_slow(MemoryRegionCache *cache,
                                            hwaddr addr, void *buf, hwaddr len);
 MemTxResult address_space_write_cached_slow(MemoryRegionCache *cache,
                                             hwaddr addr, const void *buf,
                                             hwaddr len);
 
 int memory_access_size(MemoryRegion *mr, unsigned l, hwaddr addr);
 bool prepare_mmio_access(MemoryRegion *mr);
 
 static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
 {
     if (is_write) {
         return memory_region_is_ram(mr) && !mr->readonly &&
                !mr->rom_device && !memory_region_is_ram_device(mr);
     } else {
         return (memory_region_is_ram(mr) && !memory_region_is_ram_device(mr)) ||
                memory_region_is_romd(mr);
     }
 }
 
 /**
  * address_space_read: read from an address space.
  *
  * Return a MemTxResult indicating whether the operation succeeded
  * or failed (eg unassigned memory, device rejected the transaction,
  * IOMMU fault).  Called within RCU critical section.
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @attrs: memory transaction attributes
  * @buf: buffer with the data transferred
  * @len: length of the data transferred
  */
 static inline __attribute__((__always_inline__))
 MemTxResult address_space_read(AddressSpace *as, hwaddr addr,
                                MemTxAttrs attrs, void *buf,
                                hwaddr len)
 {
     MemTxResult result = MEMTX_OK;
     hwaddr l, addr1;
     void *ptr;
     MemoryRegion *mr;
     FlatView *fv;
 
     if (__builtin_constant_p(len)) {
         if (len) {
             RCU_READ_LOCK_GUARD();
             fv = address_space_to_flatview(as);
             l = len;
             mr = flatview_translate(fv, addr, &addr1, &l, false, attrs);
             if (len == l && memory_access_is_direct(mr, false)) {
                 ptr = qemu_map_ram_ptr(mr->ram_block, addr1);
                 memcpy(buf, ptr, len);
             } else {
                 result = flatview_read_continue(fv, addr, attrs, buf, len,
                                                 addr1, l, mr);
             }
         }
     } else {
         result = address_space_read_full(as, addr, attrs, buf, len);
     }
     return result;
 }
 
 /**
  * address_space_read_cached: read from a cached RAM region
  *
  * @cache: Cached region to be addressed
  * @addr: address relative to the base of the RAM region
  * @buf: buffer with the data transferred
  * @len: length of the data transferred
  */
 static inline MemTxResult
 address_space_read_cached(MemoryRegionCache *cache, hwaddr addr,
                           void *buf, hwaddr len)
 {
     assert(addr < cache->len && len <= cache->len - addr);
     fuzz_dma_read_cb(cache->xlat + addr, len, cache->mrs.mr);
     if (likely(cache->ptr)) {
         memcpy(buf, cache->ptr + addr, len);
         return MEMTX_OK;
     } else {
         return address_space_read_cached_slow(cache, addr, buf, len);
     }
 }
 
 /**
  * address_space_write_cached: write to a cached RAM region
  *
  * @cache: Cached region to be addressed
  * @addr: address relative to the base of the RAM region
  * @buf: buffer with the data transferred
  * @len: length of the data transferred
  */
 static inline MemTxResult
 address_space_write_cached(MemoryRegionCache *cache, hwaddr addr,
                            const void *buf, hwaddr len)
 {
     assert(addr < cache->len && len <= cache->len - addr);
     if (likely(cache->ptr)) {
         memcpy(cache->ptr + addr, buf, len);
         return MEMTX_OK;
     } else {
         return address_space_write_cached_slow(cache, addr, buf, len);
     }
 }
 
 /**
  * address_space_set: Fill address space with a constant byte.
  *
  * Return a MemTxResult indicating whether the operation succeeded
  * or failed (eg unassigned memory, device rejected the transaction,
  * IOMMU fault).
  *
  * @as: #AddressSpace to be accessed
  * @addr: address within that address space
  * @c: constant byte to fill the memory
  * @len: the number of bytes to fill with the constant byte
  * @attrs: memory transaction attributes
  */
 MemTxResult address_space_set(AddressSpace *as, hwaddr addr,
                               uint8_t c, hwaddr len, MemTxAttrs attrs);
 
 #ifdef NEED_CPU_H
 /* enum device_endian to MemOp.  */
 static inline MemOp devend_memop(enum device_endian end)
 {
     QEMU_BUILD_BUG_ON(DEVICE_HOST_ENDIAN != DEVICE_LITTLE_ENDIAN &&
                       DEVICE_HOST_ENDIAN != DEVICE_BIG_ENDIAN);
 
 #if HOST_BIG_ENDIAN != TARGET_BIG_ENDIAN
     /* Swap if non-host endianness or native (target) endianness */
     return (end == DEVICE_HOST_ENDIAN) ? 0 : MO_BSWAP;
 #else
     const int non_host_endianness =
         DEVICE_LITTLE_ENDIAN ^ DEVICE_BIG_ENDIAN ^ DEVICE_HOST_ENDIAN;
 
     /* In this case, native (target) endianness needs no swap.  */
     return (end == non_host_endianness) ? MO_BSWAP : 0;
 #endif
 }
 #endif
 
 /*
  * Inhibit technologies that require discarding of pages in RAM blocks, e.g.,
  * to manage the actual amount of memory consumed by the VM (then, the memory
  * provided by RAM blocks might be bigger than the desired memory consumption).
  * This *must* be set if:
  * - Discarding parts of a RAM blocks does not result in the change being
  *   reflected in the VM and the pages getting freed.
  * - All memory in RAM blocks is pinned or duplicated, invaldiating any previous
  *   discards blindly.
  * - Discarding parts of a RAM blocks will result in integrity issues (e.g.,
  *   encrypted VMs).
  * Technologies that only temporarily pin the current working set of a
  * driver are fine, because we don't expect such pages to be discarded
  * (esp. based on guest action like balloon inflation).
  *
  * This is *not* to be used to protect from concurrent discards (esp.,
  * postcopy).
  *
  * Returns 0 if successful. Returns -EBUSY if a technology that relies on
  * discards to work reliably is active.
  */
 int ram_block_discard_disable(bool state);
 
 /*
  * See ram_block_discard_disable(): only disable uncoordinated discards,
  * keeping coordinated discards (via the RamDiscardManager) enabled.
  */
 int ram_block_uncoordinated_discard_disable(bool state);
 
 /*
  * Inhibit technologies that disable discarding of pages in RAM blocks.
  *
  * Returns 0 if successful. Returns -EBUSY if discards are already set to
  * broken.
  */
 int ram_block_discard_require(bool state);
 
 /*
  * See ram_block_discard_require(): only inhibit technologies that disable
  * uncoordinated discarding of pages in RAM blocks, allowing co-existance with
  * technologies that only inhibit uncoordinated discards (via the
  * RamDiscardManager).
  */
 int ram_block_coordinated_discard_require(bool state);
 
 /*
  * Test if any discarding of memory in ram blocks is disabled.
  */
 bool ram_block_discard_is_disabled(void);
 
 /*
  * Test if any discarding of memory in ram blocks is required to work reliably.
  */
 bool ram_block_discard_is_required(void);
 
 #endif
 
 #endif