Index: /trunk/include/VBox/vmm/pdmstorageifs.h
===================================================================
--- /trunk/include/VBox/vmm/pdmstorageifs.h	(revision 64659)
+++ /trunk/include/VBox/vmm/pdmstorageifs.h	(revision 64660)
@@ -621,4 +621,26 @@
 
     /**
+     * Queries a pointer to the memory buffer for the request from the drive/device above.
+     *
+     * @returns VBox status code.
+     * @retval  VERR_NOT_SUPPORTED if this is not supported for this request.
+     * @param   pInterface      Pointer to the interface structure containing the called function pointer.
+     * @param   hIoReq          The I/O request handle.
+     * @param   pvIoReqAlloc    The allocator specific memory for this request.
+     * @param   ppvBuf          Where to store the pointer to the guest buffer on success.
+     * @param   pcbBuf          Where to store the size of the buffer on success.
+     *
+     * @note This is an optional feature of the entity implementing this interface to avoid overhead
+     *       by copying the data between buffers. If NULL it is not supported at all and the caller
+     *       has to resort to PDMIMEDIAEXPORT::pfnIoReqCopyToBuf and PDMIMEDIAEXPORT::pfnIoReqCopyFromBuf.
+     *       The same holds when VERR_NOT_SUPPORTED is returned.
+     *
+     *       On the upside the caller of this interface might not call this method at all and just
+     *       use the before mentioned methods to copy the data between the buffers.
+     */
+    DECLR3CALLBACKMEMBER(int, pfnIoReqQueryBuf, (PPDMIMEDIAEXPORT pInterface, PDMMEDIAEXIOREQ hIoReq,
+                                                 void *pvIoReqAlloc, void **ppvBuf, size_t *pcbBuf));
+
+    /**
      * Queries the specified amount of ranges to discard from the callee for the given I/O request.
      *
@@ -660,5 +682,5 @@
 
 /** PDMIMEDIAAEXPORT interface ID. */
-#define PDMIMEDIAEXPORT_IID                  "e0a586a6-4186-40d0-8067-c754b6585b53"
+#define PDMIMEDIAEXPORT_IID                  "0ae2e534-6c28-41d6-9a88-7f88f2cb2ff8"
 
 
Index: /trunk/src/VBox/Devices/Storage/DevAHCI.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 64659)
+++ /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 64660)
@@ -410,5 +410,7 @@
     PDMLED                          Led;
 
+#if HC_ARCH_BITS == 64
     uint32_t                        u32Alignment3;
+#endif
 
     /** Async IO Thread. */
@@ -6011,4 +6013,5 @@
         pAhciPort->IMediaExPort.pfnIoReqCopyFromBuf        = ahciR3IoReqCopyFromBuf;
         pAhciPort->IMediaExPort.pfnIoReqCopyToBuf          = ahciR3IoReqCopyToBuf;
+        pAhciPort->IMediaExPort.pfnIoReqQueryBuf           = NULL;
         pAhciPort->IMediaExPort.pfnIoReqQueryDiscardRanges = ahciR3IoReqQueryDiscardRanges;
         pAhciPort->IMediaExPort.pfnIoReqStateChanged       = ahciR3IoReqStateChanged;
Index: /trunk/src/VBox/Devices/Storage/DevBusLogic.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DevBusLogic.cpp	(revision 64659)
+++ /trunk/src/VBox/Devices/Storage/DevBusLogic.cpp	(revision 64660)
@@ -4157,4 +4157,5 @@
         pDevice->IMediaExPort.pfnIoReqCopyFromBuf        = buslogicR3IoReqCopyFromBuf;
         pDevice->IMediaExPort.pfnIoReqCopyToBuf          = buslogicR3IoReqCopyToBuf;
+        pDevice->IMediaExPort.pfnIoReqQueryBuf           = NULL;
         pDevice->IMediaExPort.pfnIoReqQueryDiscardRanges = NULL;
         pDevice->IMediaExPort.pfnIoReqStateChanged       = buslogicR3IoReqStateChanged;
Index: /trunk/src/VBox/Devices/Storage/DevLsiLogicSCSI.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DevLsiLogicSCSI.cpp	(revision 64659)
+++ /trunk/src/VBox/Devices/Storage/DevLsiLogicSCSI.cpp	(revision 64660)
@@ -5580,4 +5580,5 @@
         pDevice->IMediaExPort.pfnIoReqCopyFromBuf        = lsilogicR3IoReqCopyFromBuf;
         pDevice->IMediaExPort.pfnIoReqCopyToBuf          = lsilogicR3IoReqCopyToBuf;
+        pDevice->IMediaExPort.pfnIoReqQueryBuf           = NULL;
         pDevice->IMediaExPort.pfnIoReqQueryDiscardRanges = NULL;
         pDevice->IMediaExPort.pfnIoReqStateChanged       = lsilogicR3IoReqStateChanged;
Index: /trunk/src/VBox/Devices/Storage/DrvSCSI.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DrvSCSI.cpp	(revision 64659)
+++ /trunk/src/VBox/Devices/Storage/DrvSCSI.cpp	(revision 64660)
@@ -1327,4 +1327,5 @@
     pThis->IPortEx.pfnIoReqCopyFromBuf          = drvscsiIoReqCopyFromBuf;
     pThis->IPortEx.pfnIoReqCopyToBuf            = drvscsiIoReqCopyToBuf;
+    pThis->IPortEx.pfnIoReqQueryBuf             = NULL;
     pThis->IPortEx.pfnIoReqQueryDiscardRanges   = drvscsiIoReqQueryDiscardRanges;
     pThis->IPortEx.pfnIoReqStateChanged         = drvscsiIoReqStateChanged;