/* $Id: bs3-cmn-ExtCtxGetSize.c $ */
/** @file
 * BS3Kit - Bs3ExtCtxGetSize
 */

/*
 * Copyright (C) 2007-2019 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.
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#include "bs3kit-template-header.h"
#include <iprt/asm-amd64-x86.h>


#undef Bs3ExtCtxGetSize
BS3_CMN_DEF(uint16_t, Bs3ExtCtxGetSize,(uint64_t BS3_FAR *pfFlags))
{
    uint32_t fEcx, fEdx;
    *pfFlags = 0;

    ASMCpuIdExSlow(1, 0, 0, 0, NULL, NULL, &fEcx, &fEdx);
#if 1 /* To disable xsave/xrstor till IEM groks it... */
    if (fEcx & X86_CPUID_FEATURE_ECX_XSAVE)
    {
        uint32_t fEax;
        ASMCpuIdExSlow(13, 0, 0, 0, &fEax, NULL, &fEcx, &fEdx);
        if (   fEcx >= sizeof(X86FXSTATE) + sizeof(X86XSAVEHDR)
            && fEcx < _32K)
        {
            *pfFlags = fEax | ((uint64_t)fEdx << 32);
            return RT_UOFFSETOF(BS3EXTCTX, Ctx) + RT_ALIGN(fEcx, 256);
        }
    }
#endif
    if (fEdx & X86_CPUID_FEATURE_EDX_FXSR)
        return RT_UOFFSETOF(BS3EXTCTX, Ctx) + sizeof(X86FXSTATE);
    return RT_UOFFSETOF(BS3EXTCTX, Ctx) + sizeof(X86FPUSTATE);
}