/* $Id: GenericRequest.cpp 109079 2016-07-22 19:16:33Z bird $ */
/** @file
 * VBoxGuestLibR0 - Generic VMMDev request management.
 */

/*
 * Copyright (C) 2006-2016 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */

#include "VBGLInternal.h"
#include <iprt/asm.h>
#include <iprt/asm-amd64-x86.h>
#include <iprt/assert.h>
#include <iprt/string.h>

DECLVBGL(int) VbglGRVerify(const VMMDevRequestHeader * pReq, size_t cbReq)
{
	size_t cbReqExpected;

	if (RT_UNLIKELY(!pReq || cbReq < sizeof(VMMDevRequestHeader))) {
		dprintf(("VbglGRVerify: Invalid parameter: pReq = %p, cbReq = %zu\n", pReq, cbReq));
		return VERR_INVALID_PARAMETER;
	}

	if (RT_UNLIKELY(pReq->size > cbReq)) {
		dprintf(("VbglGRVerify: request size %u > buffer size %zu\n",
			 pReq->size, cbReq));
		return VERR_INVALID_PARAMETER;
	}

	/* The request size must correspond to the request type. */
	cbReqExpected = vmmdevGetRequestSize(pReq->requestType);
	if (RT_UNLIKELY(cbReq < cbReqExpected)) {
		dprintf(("VbglGRVerify: buffer size %zu < expected size %zu\n",
			 cbReq, cbReqExpected));
		return VERR_INVALID_PARAMETER;
	}

	if (cbReqExpected == cbReq) {
		/*
		 * This is most likely a fixed size request, and in this case the
		 * request size must be also equal to the expected size.
		 */
		if (RT_UNLIKELY(pReq->size != cbReqExpected)) {
			dprintf(("VbglGRVerify: request size %u != expected size %zu\n", pReq->size, cbReqExpected));
			return VERR_INVALID_PARAMETER;
		}

		return VINF_SUCCESS;
	}

	/*
	 * This can be a variable size request. Check the request type and limit the size
	 * to VMMDEV_MAX_VMMDEVREQ_SIZE, which is max size supported by the host.
	 *
	 * Note: Keep this list sorted for easier human lookup!
	 */
	if (pReq->requestType == VMMDevReq_ChangeMemBalloon
#ifdef VBOX_WITH_64_BITS_GUESTS
	    || pReq->requestType == VMMDevReq_HGCMCall32
	    || pReq->requestType == VMMDevReq_HGCMCall64
#else
	    || pReq->requestType == VMMDevReq_HGCMCall
#endif
	    || pReq->requestType == VMMDevReq_RegisterSharedModule
	    || pReq->requestType == VMMDevReq_ReportGuestUserState
	    || pReq->requestType == VMMDevReq_LogString
	    || pReq->requestType == VMMDevReq_SetPointerShape
	    || pReq->requestType == VMMDevReq_VideoSetVisibleRegion) {
		if (RT_UNLIKELY(cbReq > VMMDEV_MAX_VMMDEVREQ_SIZE)) {
			dprintf(("VbglGRVerify: VMMDevReq_LogString: buffer size %zu too big\n", cbReq));
			return VERR_BUFFER_OVERFLOW;
					 /** @todo is this error code ok? */
		}
	} else {
		dprintf(("VbglGRVerify: request size %u > buffer size %zu\n",
			 pReq->size, cbReq));
		return VERR_IO_BAD_LENGTH;
				   /** @todo is this error code ok? */
	}

	return VINF_SUCCESS;
}

DECLVBGL(int)VbglGRAlloc(VMMDevRequestHeader ** ppReq, size_t cbReq,
			 VMMDevRequestType enmReqType)
{
	int rc = vbglR0Enter();
	if (RT_SUCCESS(rc)) {
		if (ppReq && cbReq >= sizeof(VMMDevRequestHeader)
		    && cbReq == (uint32_t) cbReq) {
			VMMDevRequestHeader *pReq =
			    (VMMDevRequestHeader *) VbglPhysHeapAlloc((uint32_t)
								      cbReq);
			AssertMsgReturn(pReq,
					("VbglGRAlloc: no memory (cbReq=%u)\n",
					 cbReq), VERR_NO_MEMORY);
			memset(pReq, 0xAA, cbReq);

			pReq->size = (uint32_t) cbReq;
			pReq->version = VMMDEV_REQUEST_HEADER_VERSION;
			pReq->requestType = enmReqType;
			pReq->rc = VERR_GENERAL_FAILURE;
			pReq->reserved1 = 0;
			pReq->reserved2 = 0;

			*ppReq = pReq;
			rc = VINF_SUCCESS;
		} else {
			dprintf(("VbglGRAlloc: Invalid parameter: ppReq=%p cbReq=%u\n", ppReq, cbReq));
			rc = VERR_INVALID_PARAMETER;
		}
	}
	return rc;
}

DECLVBGL(int)VbglGRPerform(VMMDevRequestHeader * pReq)
{
	int rc = vbglR0Enter();
	if (RT_SUCCESS(rc)) {
		if (pReq) {
			RTCCPHYS PhysAddr = VbglPhysHeapGetPhysAddr(pReq);
			if (PhysAddr != 0 && PhysAddr < _4G) {	/* Port IO is 32 bit. */
				ASMOutU32(g_vbgldata.portVMMDev +
					  VMMDEV_PORT_OFF_REQUEST,
					  (uint32_t) PhysAddr);
				/* Make the compiler aware that the host has changed memory. */
				ASMCompilerBarrier();
				rc = pReq->rc;
			} else
				rc = VERR_VBGL_INVALID_ADDR;
		} else
			rc = VERR_INVALID_PARAMETER;
	}
	return rc;
}

DECLVBGL(void)VbglGRFree(VMMDevRequestHeader * pReq)
{
	int rc = vbglR0Enter();
	if (RT_SUCCESS(rc))
		VbglPhysHeapFree(pReq);
}
