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30 #ifndef __MEM_BACKDOOR_HH__
31 #define __MEM_BACKDOOR_HH__
37 #include "base/addr_range.hh"
38 #include "base/callback.hh"
43 // Callbacks from this back door are set up using a callable which accepts
44 // a const reference to this back door as their only parameter.
45 typedef std::function<void(const MemBackdoor &backdoor)> CbFunction;
48 // This wrapper class holds the callables described above so that they
49 // can be stored in a generic CallbackQueue.
50 class Callback : public ::Callback
53 Callback(MemBackdoor &bd, CbFunction cb) :
54 _backdoor(bd), cbFunction(cb)
57 void process() override { cbFunction(_backdoor); }
58 // It looks like this is only called when the CallbackQueue is
59 // destroyed and this Callback is currently in the queue.
60 void autoDestruct() override { delete this; }
62 MemBackdoor &backdoor() { return _backdoor; }
65 MemBackdoor &_backdoor;
66 CbFunction cbFunction;
71 // How data is allowed to be accessed through this backdoor.
77 // The range in the guest address space covered by this back door.
78 const AddrRange &range() const { return _range; }
79 void range(const AddrRange &r) { _range = r; }
81 // A pointer to the data accessible through this back door.
82 uint8_t *ptr() const { return _ptr; }
83 void ptr(uint8_t *p) { _ptr = p; }
86 * Helper functions to make it easier to set/check particular flags.
89 bool readable() const { return _flags & Readable; }
94 _flags = (Flags)(_flags | Readable);
96 _flags = (Flags)(_flags & ~Readable);
99 bool writeable() const { return _flags & Writeable; }
104 _flags = (Flags)(_flags | Writeable);
106 _flags = (Flags)(_flags & ~Writeable);
109 Flags flags() const { return _flags; }
110 void flags(Flags f) { _flags = f; }
112 MemBackdoor(AddrRange r, uint8_t *p, Flags flags) :
113 invalidationCallbacks(new CallbackQueue),
114 _range(r), _ptr(p), _flags(flags)
117 MemBackdoor() : MemBackdoor(AddrRange(), nullptr, NoAccess)
120 // Set up a callable to be called when this back door is invalidated. This
121 // lets holders update their bookkeeping to remove any references to it,
122 // and/or to propogate that invalidation to other interested parties.
124 addInvalidationCallback(CbFunction func)
126 auto *cb = new MemBackdoor::Callback(*this, func);
128 invalidationCallbacks->add(cb);
131 // Notify and clear invalidation callbacks when the data in the backdoor
132 // structure is no longer valid/current. The backdoor might then be
133 // updated or even deleted without having to worry about stale data being
138 invalidationCallbacks->process();
139 // Delete and recreate the callback queue to ensure the callback
140 // objects are deleted.
141 invalidationCallbacks.reset(new CallbackQueue());
145 std::unique_ptr<CallbackQueue> invalidationCallbacks;
152 typedef MemBackdoor *MemBackdoorPtr;
154 #endif //__MEM_BACKDOOR_HH__