hw/dataplane/hostmem.h

   1 /*
   2  * Thread-safe guest to host memory mapping
   3  *
   4  * Copyright 2012 Red Hat, Inc. and/or its affiliates
   5  *
   6  * Authors:
   7  *   Stefan Hajnoczi <stefanha@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #ifndef HOSTMEM_H
  15 #define HOSTMEM_H
  16
  17 #include "exec/memory.h"
  18 #include "qemu/thread.h"
  19
  20 typedef struct {
  21     void *host_addr;
  22     hwaddr guest_addr;
  23     uint64_t size;
  24     bool readonly;
  25 } HostMemRegion;
  26
  27 typedef struct {
  28     /* The listener is invoked when regions change and a new list of regions is
  29      * built up completely before they are installed.
  30      */
  31     MemoryListener listener;
  32     HostMemRegion *new_regions;
  33     size_t num_new_regions;
  34
  35     /* Current regions are accessed from multiple threads either to lookup
  36      * addresses or to install a new list of regions.  The lock protects the
  37      * pointer and the regions.
  38      */
  39     QemuMutex current_regions_lock;
  40     HostMemRegion *current_regions;
  41     size_t num_current_regions;
  42 } HostMem;
  43
  44 void hostmem_init(HostMem *hostmem);
  45 void hostmem_finalize(HostMem *hostmem);
  46
  47 /**
  48  * Map a guest physical address to a pointer
  49  *
  50  * Note that there is map/unmap mechanism here.  The caller must ensure that
  51  * mapped memory is no longer used across events like hot memory unplug.  This
  52  * can be done with other mechanisms like bdrv_drain_all() that quiesce
  53  * in-flight I/O.
  54  */
  55 void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write);
  56
  57 #endif /* HOSTMEM_H */