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[apple/xnu.git] / iokit / Kernel / IOMultiMemoryDescriptor.cpp
index ea706f33abaddbc788282c4390ac4ffb00459afe..d70531265e01d5bf42f2ca02ad0498f421b16d24 100644 (file)
@@ -1,23 +1,29 @@
 /*
  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
- * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- * 
- * @APPLE_LICENSE_HEADER_END@
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 #include <IOKit/IOLib.h>
 #define super IOMemoryDescriptor
 OSDefineMetaClassAndStructors(IOMultiMemoryDescriptor, IOMemoryDescriptor)
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-bool IOMultiMemoryDescriptor::initWithAddress(
-                                  void *      /* address       */ ,
-                                  IOByteCount /* withLength    */ ,
-                                  IODirection /* withDirection */ )
+IOMultiMemoryDescriptor * IOMultiMemoryDescriptor::withDescriptors(
+       IOMemoryDescriptor * *descriptors,
+       UInt32                withCount,
+       IODirection           withDirection,
+       bool                  asReference )
 {
-    return false;
+       //
+       // Create a new IOMultiMemoryDescriptor.  The "buffer" is made up of several
+       // memory descriptors, that are to be chained end-to-end to make up a single
+       // memory descriptor.
+       //
+       // Passing the ranges as a reference will avoid an extra allocation.
+       //
+
+       IOMultiMemoryDescriptor * me = new IOMultiMemoryDescriptor;
+
+       if (me && me->initWithDescriptors(
+                   /* descriptors   */ descriptors,
+                   /* withCount     */ withCount,
+                   /* withDirection */ withDirection,
+                   /* asReference   */ asReference ) == false) {
+               me->release();
+               me = NULL;
+       }
+
+       return me;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-bool IOMultiMemoryDescriptor::initWithAddress(
-                                  vm_address_t /* address       */ ,
-                                  IOByteCount  /* withLength    */ ,
-                                  IODirection  /* withDirection */ ,
-                                  task_t       /* withTask      */ )
+bool
+IOMultiMemoryDescriptor::initWithDescriptors(
+       IOMemoryDescriptor ** descriptors,
+       UInt32                withCount,
+       IODirection           withDirection,
+       bool                  asReference )
 {
-    return false;
+       unsigned index;
+       IOOptionBits copyFlags;
+       //
+       // Initialize an IOMultiMemoryDescriptor. The "buffer" is made up of several
+       // memory descriptors, that are to be chained end-to-end to make up a single
+       // memory descriptor.
+       //
+       // Passing the ranges as a reference will avoid an extra allocation.
+       //
+
+       assert(descriptors);
+
+       // Release existing descriptors, if any
+       if (_descriptors) {
+               for (unsigned index = 0; index < _descriptorsCount; index++) {
+                       _descriptors[index]->release();
+               }
+
+               if (_descriptorsIsAllocated) {
+                       IODelete(_descriptors, IOMemoryDescriptor *, _descriptorsCount);
+               }
+       } else {
+               // Ask our superclass' opinion.
+               if (super::init() == false) {
+                       return false;
+               }
+       }
+
+       // Initialize our minimal state.
+
+       _descriptors            = NULL;
+       _descriptorsCount       = withCount;
+       _descriptorsIsAllocated = asReference ? false : true;
+       _flags                  = withDirection;
+#ifndef __LP64__
+       _direction              = (IODirection) (_flags & kIOMemoryDirectionMask);
+#endif /* !__LP64__ */
+       _length                 = 0;
+       _mappings               = NULL;
+       _tag                    = 0;
+
+       if (asReference) {
+               _descriptors = descriptors;
+       } else {
+               _descriptors = IONew(IOMemoryDescriptor *, withCount);
+               if (_descriptors == NULL) {
+                       return false;
+               }
+
+               bcopy( /* from  */ descriptors,
+                   /* to    */ _descriptors,
+                   /* bytes */ withCount * sizeof(IOMemoryDescriptor *));
+       }
+
+       for (index = 0; index < withCount; index++) {
+               descriptors[index]->retain();
+               _length += descriptors[index]->getLength();
+               if (_tag == 0) {
+                       _tag = descriptors[index]->getTag();
+               }
+               assert(descriptors[index]->getDirection() ==
+                   (withDirection & kIOMemoryDirectionMask));
+       }
+
+       enum { kCopyFlags = kIOMemoryBufferPageable };
+       copyFlags = 0;
+       for (index = 0; index < withCount; index++) {
+               if (!index) {
+                       copyFlags =  (kCopyFlags & descriptors[index]->_flags);
+               } else if (copyFlags != (kCopyFlags & descriptors[index]->_flags)) {
+                       break;
+               }
+       }
+       if (index < withCount) {
+               return false;
+       }
+       _flags |= copyFlags;
+
+       return true;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-bool IOMultiMemoryDescriptor::initWithPhysicalAddress(
-                                  IOPhysicalAddress /* address       */ ,
-                                  IOByteCount       /* withLength    */ ,
-                                  IODirection       /* withDirection */ )
+void
+IOMultiMemoryDescriptor::free()
 {
-    return false;
-}
+       //
+       // Free all of this object's outstanding resources.
+       //
 
+       if (_descriptors) {
+               for (unsigned index = 0; index < _descriptorsCount; index++) {
+                       _descriptors[index]->release();
+               }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+               if (_descriptorsIsAllocated) {
+                       IODelete(_descriptors, IOMemoryDescriptor *, _descriptorsCount);
+               }
+       }
 
-bool IOMultiMemoryDescriptor::initWithPhysicalRanges(
-                                  IOPhysicalRange * /* ranges        */ ,
-                                  UInt32            /* withCount     */ ,
-                                  IODirection       /* withDirection */ ,
-                                  bool              /* asReference   */ )
-{
-    return false;
+       super::free();
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-bool IOMultiMemoryDescriptor::initWithRanges(
-                                  IOVirtualRange * /* ranges        */ ,
-                                  UInt32           /* withCount     */ ,
-                                  IODirection      /* withDirection */ ,
-                                  task_t           /* withTask      */ ,
-                                  bool             /* asReference   */ )
+IOReturn
+IOMultiMemoryDescriptor::prepare(IODirection forDirection)
 {
-    return false;
+       //
+       // Prepare the memory for an I/O transfer.
+       //
+       // This involves paging in the memory and wiring it down for the duration
+       // of the transfer.  The complete() method finishes the processing of the
+       // memory after the I/O transfer finishes.
+       //
+
+       unsigned index;
+       IOReturn status = kIOReturnInternalError;
+       IOReturn statusUndo;
+
+       if (forDirection == kIODirectionNone) {
+               forDirection = getDirection();
+       }
+
+       for (index = 0; index < _descriptorsCount; index++) {
+               status = _descriptors[index]->prepare(forDirection);
+               if (status != kIOReturnSuccess) {
+                       break;
+               }
+       }
+
+       if (status != kIOReturnSuccess) {
+               for (unsigned indexUndo = 0; indexUndo < index; indexUndo++) {
+                       statusUndo = _descriptors[indexUndo]->complete(forDirection);
+                       assert(statusUndo == kIOReturnSuccess);
+               }
+       }
+
+       return status;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-IOMultiMemoryDescriptor * IOMultiMemoryDescriptor::withDescriptors(
-                                  IOMemoryDescriptor ** descriptors,
-                                  UInt32                withCount,
-                                  IODirection           withDirection,
-                                  bool                  asReference )
+IOReturn
+IOMultiMemoryDescriptor::complete(IODirection forDirection)
 {
-    //
-    // Create a new IOMultiMemoryDescriptor.  The "buffer" is made up of several
-    // memory descriptors, that are to be chained end-to-end to make up a single
-    // memory descriptor.
-    //
-    // Passing the ranges as a reference will avoid an extra allocation.
-    //
-
-    IOMultiMemoryDescriptor * me = new IOMultiMemoryDescriptor;
-    
-    if ( me && me->initWithDescriptors(
-                                  /* descriptors   */ descriptors,
-                                  /* withCount     */ withCount,
-                                  /* withDirection */ withDirection,
-                                  /* asReference   */ asReference ) == false )
-    {
-           me->release();
-           me = 0;
-    }
-
-    return me;
+       //
+       // Complete processing of the memory after an I/O transfer finishes.
+       //
+       // This method shouldn't be called unless a prepare() was previously issued;
+       // the prepare() and complete() must occur in pairs, before and after an I/O
+       // transfer.
+       //
+
+       IOReturn status;
+       IOReturn statusFinal = kIOReturnSuccess;
+
+       if (forDirection == kIODirectionNone) {
+               forDirection = getDirection();
+       }
+
+       for (unsigned index = 0; index < _descriptorsCount; index++) {
+               status = _descriptors[index]->complete(forDirection);
+               if (status != kIOReturnSuccess) {
+                       statusFinal = status;
+               }
+               assert(status == kIOReturnSuccess);
+       }
+
+       return statusFinal;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-bool IOMultiMemoryDescriptor::initWithDescriptors(
-                                  IOMemoryDescriptor ** descriptors,
-                                  UInt32                withCount,
-                                  IODirection           withDirection,
-                                  bool                  asReference )
+addr64_t
+IOMultiMemoryDescriptor::getPhysicalSegment(IOByteCount   offset,
+    IOByteCount * length,
+    IOOptionBits  options)
 {
-    //
-    // Initialize an IOMultiMemoryDescriptor. The "buffer" is made up of several
-    // memory descriptors, that are to be chained end-to-end to make up a single
-    // memory descriptor.
-    //
-    // Passing the ranges as a reference will avoid an extra allocation.
-    //
-
-    assert(descriptors);
-    assert(withCount);
-
-    // Release existing descriptors, if any
-    if ( _descriptors )
-    {
-        for ( unsigned index = 0; index < _descriptorsCount; index++ ) 
-            _descriptors[index]->release();
-
-        if ( _descriptorsIsAllocated )
-            IODelete(_descriptors, IOMemoryDescriptor *, _descriptorsCount);
-    } else {
-        // Ask our superclass' opinion.
-        if ( super::init() == false )  return false;
-    }
-    
-    // Initialize our minimal state.
-
-    _descriptors            = 0;
-    _descriptorsCount       = withCount;
-    _descriptorsIsAllocated = asReference ? false : true;
-    _direction              = withDirection;
-    _length                 = 0;
-    _mappings               = 0;
-    _tag                    = 0;
-
-    if ( asReference )
-    {
-        _descriptors = descriptors;
-    }
-    else
-    {
-        _descriptors = IONew(IOMemoryDescriptor *, withCount);
-        if ( _descriptors == 0 )  return false;
-
-        bcopy( /* from  */ descriptors,
-               /* to    */ _descriptors,
-               /* bytes */ withCount * sizeof(IOMemoryDescriptor *) );
-    }
-
-    for ( unsigned index = 0; index < withCount; index++ ) 
-    {
-        descriptors[index]->retain();
-        _length += descriptors[index]->getLength();
-        if ( _tag == 0 )  _tag = descriptors[index]->getTag();
-        assert(descriptors[index]->getDirection() == withDirection);
-    }
-
-    return true;
+       //
+       // This method returns the physical address of the byte at the given offset
+       // into the memory,  and optionally the length of the physically contiguous
+       // segment from that offset.
+       //
+
+       assert(offset <= _length);
+
+       for (unsigned index = 0; index < _descriptorsCount; index++) {
+               if (offset < _descriptors[index]->getLength()) {
+                       return _descriptors[index]->getPhysicalSegment(offset, length, options);
+               }
+               offset -= _descriptors[index]->getLength();
+       }
+
+       if (length) {
+               *length = 0;
+       }
+
+       return 0;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+#include "IOKitKernelInternal.h"
 
-void IOMultiMemoryDescriptor::free()
+IOReturn
+IOMultiMemoryDescriptor::doMap(vm_map_t           __addressMap,
+    IOVirtualAddress *  __address,
+    IOOptionBits       options,
+    IOByteCount        __offset,
+    IOByteCount        __length)
 {
-    //
-    // Free all of this object's outstanding resources.
-    //
-
-    if ( _descriptors )
-    {
-        for ( unsigned index = 0; index < _descriptorsCount; index++ ) 
-            _descriptors[index]->release();
-
-        if ( _descriptorsIsAllocated )
-            IODelete(_descriptors, IOMemoryDescriptor *, _descriptorsCount);
-    }
-
-    super::free();
+       IOMemoryMap *     mapping = (IOMemoryMap *) *__address;
+       vm_map_t          map     = mapping->fAddressMap;
+       mach_vm_size_t    offset  = mapping->fOffset;
+       mach_vm_size_t    length  = mapping->fLength;
+       mach_vm_address_t address = mapping->fAddress;
+
+       kern_return_t     err;
+       IOOptionBits      subOptions;
+       mach_vm_size_t    mapOffset;
+       mach_vm_size_t    bytesRemaining, chunk;
+       mach_vm_address_t nextAddress;
+       IOMemoryDescriptorMapAllocRef ref;
+       vm_prot_t                     prot;
+
+       do{
+               prot = VM_PROT_READ;
+               if (!(kIOMapReadOnly & options)) {
+                       prot |= VM_PROT_WRITE;
+               }
+
+               if (kIOMapOverwrite & options) {
+                       if ((map == kernel_map) && (kIOMemoryBufferPageable & _flags)) {
+                               map = IOPageableMapForAddress(address);
+                       }
+                       err = KERN_SUCCESS;
+               } else {
+                       ref.map     = map;
+                       ref.tag     = IOMemoryTag(map);
+                       ref.options = options;
+                       ref.size    = length;
+                       ref.prot    = prot;
+                       if (options & kIOMapAnywhere) {
+                               // vm_map looks for addresses above here, even when VM_FLAGS_ANYWHERE
+                               ref.mapped = 0;
+                       } else {
+                               ref.mapped = mapping->fAddress;
+                       }
+
+                       if ((ref.map == kernel_map) && (kIOMemoryBufferPageable & _flags)) {
+                               err = IOIteratePageableMaps(ref.size, &IOMemoryDescriptorMapAlloc, &ref);
+                       } else {
+                               err = IOMemoryDescriptorMapAlloc(ref.map, &ref);
+                       }
+
+                       if (KERN_SUCCESS != err) {
+                               break;
+                       }
+
+                       address = ref.mapped;
+                       mapping->fAddress = address;
+               }
+
+               mapOffset = offset;
+               bytesRemaining = length;
+               nextAddress = address;
+               assert(mapOffset <= _length);
+               subOptions = (options & ~kIOMapAnywhere) | kIOMapOverwrite;
+
+               for (unsigned index = 0; bytesRemaining && (index < _descriptorsCount); index++) {
+                       chunk = _descriptors[index]->getLength();
+                       if (mapOffset >= chunk) {
+                               mapOffset -= chunk;
+                               continue;
+                       }
+                       chunk -= mapOffset;
+                       if (chunk > bytesRemaining) {
+                               chunk = bytesRemaining;
+                       }
+                       IOMemoryMap * subMap;
+                       subMap = _descriptors[index]->createMappingInTask(mapping->fAddressTask, nextAddress, subOptions, mapOffset, chunk );
+                       if (!subMap) {
+                               break;
+                       }
+                       subMap->release(); // kIOMapOverwrite means it will not deallocate
+
+                       bytesRemaining -= chunk;
+                       nextAddress += chunk;
+                       mapOffset = 0;
+               }
+               if (bytesRemaining) {
+                       err = kIOReturnUnderrun;
+               }
+       }while (false);
+
+       if (kIOReturnSuccess == err) {
+#if IOTRACKING
+               IOTrackingAddUser(gIOMapTracking, &mapping->fTracking, mapping->fLength);
+#endif
+       }
+
+       return err;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-IOReturn IOMultiMemoryDescriptor::prepare(IODirection forDirection)
+IOReturn
+IOMultiMemoryDescriptor::setPurgeable( IOOptionBits newState,
+    IOOptionBits * oldState )
 {
-    //
-    // Prepare the memory for an I/O transfer.
-    //
-    // This involves paging in the memory and wiring it down for the duration
-    // of the transfer.  The complete() method finishes the processing of the
-    // memory after the I/O transfer finishes.
-    //
-
-    unsigned index;
-    IOReturn status = kIOReturnInternalError;
-    IOReturn statusUndo;
-
-    if ( forDirection == kIODirectionNone )
-    {
-        forDirection = _direction;
-    }
-
-    for ( index = 0; index < _descriptorsCount; index++ ) 
-    {
-        status = _descriptors[index]->prepare(forDirection);
-        if ( status != kIOReturnSuccess )  break;
-    }
-
-    if ( status != kIOReturnSuccess )
-    {
-        for ( unsigned indexUndo = 0; indexUndo <= index; indexUndo++ )
-        {
-            statusUndo = _descriptors[index]->complete(forDirection);
-            assert(statusUndo == kIOReturnSuccess);
-        }
-    }
-
-    return status;
+       IOReturn     err;
+       IOOptionBits totalState, state;
+
+       totalState = kIOMemoryPurgeableNonVolatile;
+       err = kIOReturnSuccess;
+       for (unsigned index = 0; index < _descriptorsCount; index++) {
+               err = _descriptors[index]->setPurgeable(newState, &state);
+               if (kIOReturnSuccess != err) {
+                       break;
+               }
+
+               if (kIOMemoryPurgeableEmpty == state) {
+                       totalState = kIOMemoryPurgeableEmpty;
+               } else if (kIOMemoryPurgeableEmpty == totalState) {
+                       continue;
+               } else if (kIOMemoryPurgeableVolatile == totalState) {
+                       continue;
+               } else if (kIOMemoryPurgeableVolatile == state) {
+                       totalState = kIOMemoryPurgeableVolatile;
+               } else {
+                       totalState = kIOMemoryPurgeableNonVolatile;
+               }
+       }
+       if (oldState) {
+               *oldState = totalState;
+       }
+
+       return err;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-IOReturn IOMultiMemoryDescriptor::complete(IODirection forDirection)
+IOReturn
+IOMultiMemoryDescriptor::setOwnership( task_t newOwner,
+    int newLedgerTag,
+    IOOptionBits newLedgerOptions )
 {
-    //
-    // Complete processing of the memory after an I/O transfer finishes.
-    //
-    // This method shouldn't be called unless a prepare() was previously issued;
-    // the prepare() and complete() must occur in pairs, before and after an I/O
-    // transfer.
-    //
-
-    IOReturn status;
-    IOReturn statusFinal = kIOReturnSuccess;
-
-    if ( forDirection == kIODirectionNone )
-    {
-        forDirection = _direction;
-    }
-
-    for ( unsigned index = 0; index < _descriptorsCount; index++ ) 
-    {
-        status = _descriptors[index]->complete(forDirection);
-        if ( status != kIOReturnSuccess )  statusFinal = status;
-        assert(status == kIOReturnSuccess);
-    }
-
-    return statusFinal;
-}
+       IOReturn     err;
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+       if (iokit_iomd_setownership_enabled == FALSE) {
+               return kIOReturnUnsupported;
+       }
 
-IOPhysicalAddress IOMultiMemoryDescriptor::getPhysicalSegment(
-                                                       IOByteCount   offset,
-                                                       IOByteCount * length )
-{
-    //
-    // This method returns the physical address of the byte at the given offset
-    // into the memory,  and optionally the length of the physically contiguous
-    // segment from that offset.
-    //
-
-    assert(offset <= _length);
-
-    for ( unsigned index = 0; index < _descriptorsCount; index++ ) 
-    {
-        if ( offset < _descriptors[index]->getLength() )
-        {
-            return _descriptors[index]->getPhysicalSegment(offset, length);
-        }
-        offset -= _descriptors[index]->getLength();
-    }
-
-    if ( length )  *length = 0;
-
-    return 0;
-}
+       err = kIOReturnSuccess;
+       for (unsigned index = 0; index < _descriptorsCount; index++) {
+               err = _descriptors[index]->setOwnership(newOwner, newLedgerTag, newLedgerOptions);
+               if (kIOReturnSuccess != err) {
+                       break;
+               }
+       }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+       return err;
+}
 
-IOPhysicalAddress IOMultiMemoryDescriptor::getSourceSegment(
-                                                       IOByteCount   offset,
-                                                       IOByteCount * length )
+IOReturn
+IOMultiMemoryDescriptor::getPageCounts(IOByteCount * pResidentPageCount,
+    IOByteCount * pDirtyPageCount)
 {
-    //
-    // This method returns the physical address of the byte at the given offset
-    // into the memory,  and optionally the length of the physically contiguous
-    // segment from that offset.
-    //
-
-    assert(offset <= _length);
-
-    for ( unsigned index = 0; index < _descriptorsCount; index++ ) 
-    {
-        if ( offset < _descriptors[index]->getLength() )
-        {
-            return _descriptors[index]->getSourceSegment(offset, length);
-        }
-        offset -= _descriptors[index]->getLength();
-    }
-
-    if ( length )  *length = 0;
-
-    return 0;
+       IOReturn    err;
+       IOByteCount totalResidentPageCount, totalDirtyPageCount;
+       IOByteCount residentPageCount, dirtyPageCount;
+
+       err = kIOReturnSuccess;
+       totalResidentPageCount = totalDirtyPageCount = 0;
+       for (unsigned index = 0; index < _descriptorsCount; index++) {
+               err = _descriptors[index]->getPageCounts(&residentPageCount, &dirtyPageCount);
+               if (kIOReturnSuccess != err) {
+                       break;
+               }
+               totalResidentPageCount += residentPageCount;
+               totalDirtyPageCount    += dirtyPageCount;
+       }
+
+       if (pResidentPageCount) {
+               *pResidentPageCount = totalResidentPageCount;
+       }
+       if (pDirtyPageCount) {
+               *pDirtyPageCount = totalDirtyPageCount;
+       }
+
+       return err;
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-void * IOMultiMemoryDescriptor::getVirtualSegment( IOByteCount   /* offset */ ,
-                                                   IOByteCount * /* length */ )
+uint64_t
+IOMultiMemoryDescriptor::getPreparationID( void )
 {
-    return 0;
-}
+       if (!super::getKernelReserved()) {
+               return kIOPreparationIDUnsupported;
+       }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+       for (unsigned index = 0; index < _descriptorsCount; index++) {
+               uint64_t preparationID = _descriptors[index]->getPreparationID();
 
-IOByteCount IOMultiMemoryDescriptor::readBytes( IOByteCount offset,
-                                                void *      bytes,
-                                                IOByteCount withLength )
-{
-    //
-    // Copies data from the memory descriptor's buffer at the given offset, to
-    // the specified buffer.  Returns the number of bytes copied.
-    //
-
-    IOByteCount bytesCopied = 0;
-    unsigned    index;
-
-    for ( index = 0; index < _descriptorsCount; index++ ) 
-    {
-        if ( offset < _descriptors[index]->getLength() )  break;
-        offset -= _descriptors[index]->getLength();
-    }
-
-    for ( ; index < _descriptorsCount && withLength; index++)
-    {
-        IOByteCount copy   = min(_descriptors[index]->getLength(), withLength);
-        IOByteCount copied = _descriptors[index]->readBytes(offset,bytes,copy);
-
-        bytesCopied += copied;
-        if ( copied != copy )  break;
-
-        bytes = ((UInt8 *) bytes) + copied;
-        withLength -= copied;
-        offset = 0;
-    }
-
-    return bytesCopied;
-}
+               if (preparationID == kIOPreparationIDUnsupported) {
+                       return kIOPreparationIDUnsupported;
+               }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+               if (preparationID == kIOPreparationIDUnprepared) {
+                       return kIOPreparationIDUnprepared;
+               }
+       }
 
-IOByteCount IOMultiMemoryDescriptor::writeBytes( IOByteCount  offset,
-                                                 const void * bytes,
-                                                 IOByteCount  withLength )
-{
-    //
-    // Copies data to the memory descriptor's buffer at the given offset, from
-    // the specified buffer.  Returns the number of bytes copied.
-    //
-
-    IOByteCount bytesCopied = 0;
-    unsigned    index;
-
-    for ( index = 0; index < _descriptorsCount; index++ ) 
-    {
-        if ( offset < _descriptors[index]->getLength() )  break;
-        offset -= _descriptors[index]->getLength();
-    }
-
-    for ( ; index < _descriptorsCount && withLength; index++)
-    {
-        IOByteCount copy   = min(_descriptors[index]->getLength(), withLength);
-        IOByteCount copied = _descriptors[index]->writeBytes(offset,bytes,copy);
-
-        bytesCopied += copied;
-        if ( copied != copy )  break;
-
-        bytes = ((UInt8 *) bytes) + copied;
-        withLength -= copied;
-        offset = 0;
-    }
-
-    return bytesCopied;
+       super::setPreparationID();
+
+       return super::getPreparationID();
 }