int10.c

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/*
 * VideoPort driver
 *
 * Copyright (C) 2002, 2003, 2004 ReactOS Team
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
 
#include "videoprt.h"
 
#include <ndk/kefuncs.h>
#include <ndk/mmfuncs.h>
 
#define NDEBUG
#include <debug.h>
 
/* GLOBAL VARIABLES ***********************************************************/
 
#ifdef _M_IX86
/* Use the 32-bit x86 emulator by default, on NT 6.x (Vista+), or on NT 5.x
 * if the HAL has the necessary exports. Otherwise fall back to V86 mode. */
BOOLEAN VideoPortDisableX86Emulator = FALSE;
 
/* Tells whether the video address space has been initialized for VDM calls */
static BOOLEAN VDMAddressSpaceInitialized = FALSE;
#endif
 
KMUTEX VideoPortInt10Mutex;
 
 
/* X86 EMULATOR & V86 MODE INITIALIZATION *************************************/
 
#if (NTDDI_VERSION < NTDDI_VISTA) && (DLL_EXPORT_VERSION < _WIN32_WINNT_VISTA)
/*
 * x86 Emulator callbacks
 */
#include <ndk/haltypes.h> // For X86_BIOS_REGISTERS
 
static BOOLEAN
(NTAPI *x86BiosCall)(
    _In_ ULONG InterruptNumber,
    _Inout_ PX86_BIOS_REGISTERS Registers);
 
static NTSTATUS
(NTAPI *x86BiosAllocateBuffer)(
    _Inout_ PULONG Size,
    _Out_ PUSHORT Segment,
    _Out_ PUSHORT Offset);
 
static NTSTATUS
(NTAPI *x86BiosFreeBuffer)(
    _In_ USHORT Segment,
    _In_ USHORT Offset);
 
static NTSTATUS
(NTAPI *x86BiosReadMemory)(
    _In_ USHORT Segment,
    _In_ USHORT Offset,
    _Out_writes_bytes_(Size) PVOID Buffer,
    _In_ ULONG Size);
 
static NTSTATUS
(NTAPI *x86BiosWriteMemory)(
    _In_ USHORT Segment,
    _In_ USHORT Offset,
    _In_reads_bytes_(Size) PVOID Buffer,
    _In_ ULONG Size);
 
#else // (NTDDI_VERSION >= NTDDI_VISTA) || (DLL_EXPORT_VERSION >= _WIN32_WINNT_VISTA)
#include <ndk/halfuncs.h> // For x86Bios*()
#endif
 
static BOOLEAN
IntInitializeX86Emu(VOID)
{
#if (NTDDI_VERSION < NTDDI_VISTA) && (DLL_EXPORT_VERSION < _WIN32_WINNT_VISTA)
    UNICODE_STRING ImportName;
#define LOAD_IMPORT(func) \
    (RtlInitUnicodeString(&ImportName, L ## #func), \
     (func) = MmGetSystemRoutineAddress(&ImportName))
 
    if (!LOAD_IMPORT(x86BiosCall)) // Check also HalInitializeBios ?
        return FALSE; /* No emulator available */
    if (!LOAD_IMPORT(x86BiosAllocateBuffer))
        return FALSE;
    if (!LOAD_IMPORT(x86BiosFreeBuffer))
        return FALSE;
    if (!LOAD_IMPORT(x86BiosReadMemory))
        return FALSE;
    if (!LOAD_IMPORT(x86BiosWriteMemory))
        return FALSE;
#undef LOAD_IMPORT
#endif
 
    return TRUE;
}
 
#ifdef _M_IX86
 
#define IsLowV86Mem(_Seg, _Off) ((((_Seg) << 4) + (_Off)) < (0xa0000))
 
/* Those two functions below are there so that CSRSS can't access low mem.
 * Especially, MAKE IT CRASH ON NULL ACCESS */
static VOID
ProtectLowV86Mem(VOID)
{
    /* We pass a non-NULL address so that ZwAllocateVirtualMemory really does it
     * And we truncate one page to get the right range spanned. */
    PVOID BaseAddress = (PVOID)1;
    NTSTATUS Status;
    SIZE_T ViewSize = 0xa0000 - PAGE_SIZE;
 
    /* We should only do that for CSRSS */
    ASSERT(PsGetCurrentProcess() == (PEPROCESS)CsrProcess);
 
    /* Commit (again) the pages, but with PAGE_NOACCESS protection */
    Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
                                     &BaseAddress,
                                     0,
                                     &ViewSize,
                                     MEM_COMMIT,
                                     PAGE_NOACCESS);
    ASSERT(NT_SUCCESS(Status));
}
 
static VOID
UnprotectLowV86Mem(VOID)
{
    /* We pass a non-NULL address so that ZwAllocateVirtualMemory really does it
     * And we truncate one page to get the right range spanned. */
    PVOID BaseAddress = (PVOID)1;
    NTSTATUS Status;
    SIZE_T ViewSize = 0xa0000 - PAGE_SIZE;
 
    /* We should only do that for CSRSS, for the v86 address space */
    ASSERT(PsGetCurrentProcess() == (PEPROCESS)CsrProcess);
 
    /* Commit (again) the pages, but with PAGE_READWRITE protection */
    Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
                                     &BaseAddress,
                                     0,
                                     &ViewSize,
                                     MEM_COMMIT,
                                     PAGE_READWRITE);
    ASSERT(NT_SUCCESS(Status));
}
 
static inline
NTSTATUS
IntInitializeVideoAddressSpace(VOID)
{
    OBJECT_ATTRIBUTES ObjectAttributes;
    UNICODE_STRING PhysMemName = RTL_CONSTANT_STRING(L"\\Device\\PhysicalMemory");
    NTSTATUS Status;
    HANDLE PhysMemHandle;
    PVOID BaseAddress;
    LARGE_INTEGER Offset;
    SIZE_T ViewSize;
    CHAR IVTAndBda[1024 + 256];
 
    /* We should only do that for CSRSS */
    ASSERT(PsGetCurrentProcess() == (PEPROCESS)CsrProcess);
 
    /* Free the 1MB pre-reserved region. In reality, ReactOS should simply
     * support us mapping the view into the reserved area, but it doesn't. */
    BaseAddress = 0;
    ViewSize = 1024 * 1024;
    Status = ZwFreeVirtualMemory(NtCurrentProcess(),
                                 &BaseAddress,
                                 &ViewSize,
                                 MEM_RELEASE);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Couldn't unmap reserved memory (%x)\n", Status);
        return Status;
    }
 
    /* Open the physical memory section */
    InitializeObjectAttributes(&ObjectAttributes,
                               &PhysMemName,
                               OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
                               NULL,
                               NULL);
    Status = ZwOpenSection(&PhysMemHandle,
                           SECTION_ALL_ACCESS,
                           &ObjectAttributes);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Couldn't open \\Device\\PhysicalMemory\n");
        return Status;
    }
 
    /* Map the BIOS and device registers into the address space */
    Offset.QuadPart = 0xa0000;
    ViewSize = 0x100000 - 0xa0000;
    BaseAddress = (PVOID)0xa0000;
    Status = ZwMapViewOfSection(PhysMemHandle,
                                NtCurrentProcess(),
                                &BaseAddress,
                                0,
                                ViewSize,
                                &Offset,
                                &ViewSize,
                                ViewUnmap,
                                0,
                                PAGE_EXECUTE_READWRITE);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Couldn't map physical memory (%x)\n", Status);
        ZwClose(PhysMemHandle);
        return Status;
    }
 
    /* Close physical memory section handle */
    ZwClose(PhysMemHandle);
 
    if (BaseAddress != (PVOID)0xa0000)
    {
        DPRINT1("Couldn't map physical memory at the right address (was %x)\n",
                BaseAddress);
        return STATUS_UNSUCCESSFUL;
    }
 
    /* Allocate some low memory to use for the non-BIOS
     * parts of the v86 mode address space
     */
    BaseAddress = (PVOID)0x1;
    ViewSize = 0xa0000 - 0x1000;
    Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
                                     &BaseAddress,
                                     0,
                                     &ViewSize,
                                     MEM_RESERVE | MEM_COMMIT,
                                     PAGE_EXECUTE_READWRITE);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("Failed to allocate virtual memory (Status %x)\n", Status);
        return Status;
    }
    if (BaseAddress != (PVOID)0x0)
    {
        DPRINT1("Failed to allocate virtual memory at right address (was %x)\n",
                BaseAddress);
        return STATUS_UNSUCCESSFUL;
    }
 
    /* Get the real mode IVT and BDA from the kernel */
    Status = NtVdmControl(VdmInitialize, IVTAndBda);
    if (!NT_SUCCESS(Status))
    {
        DPRINT1("NtVdmControl failed (status %x)\n", Status);
        return Status;
    }
 
    /* Protect the V86 address space after this */
    ProtectLowV86Mem();
 
    /* Return success */
    VDMAddressSpaceInitialized = TRUE;
    return STATUS_SUCCESS;
}
 
#endif // _M_IX86
 
 
/* VideoPortServicesInt10 CALLBACKS *******************************************/
 
#ifdef _M_IX86
typedef struct _INT10_INTERFACE
{
    PINT10_ALLOCATE_BUFFER Int10AllocateBuffer;
    PINT10_FREE_BUFFER Int10FreeBuffer;
    PINT10_READ_MEMORY Int10ReadMemory;
    PINT10_WRITE_MEMORY Int10WriteMemory;
    PINT10_CALL_BIOS Int10CallBios;
} INT10_INTERFACE;
 
// Remark: Instead of `Int10Vtbl->`, one could use: `Int10IFace[VideoPortDisableX86Emulator].`
static const INT10_INTERFACE *Int10Vtbl; // Int10IFace[2];
#define INT10(func) Int10Vtbl->Int10##func
#else
#define INT10(func) IntInt10##func##Emu
#endif // _M_IX86
 
 
static VP_STATUS
NTAPI
IntInt10AllocateBufferEmu(
    _In_ PVOID Context,
    _Out_ PUSHORT Seg,
    _Out_ PUSHORT Off,
    _Inout_ PULONG Length)
{
    NTSTATUS Status;
 
    UNREFERENCED_PARAMETER(Context);
 
    Status = x86BiosAllocateBuffer(Length, Seg, Off);
    return (NT_SUCCESS(Status) ? NO_ERROR : ERROR_NOT_ENOUGH_MEMORY);
}
 
#ifdef _M_IX86
static VP_STATUS
NTAPI
IntInt10AllocateBufferV86(
    _In_ PVOID Context,
    _Out_ PUSHORT Seg,
    _Out_ PUSHORT Off,
    _Inout_ PULONG Length)
{
    NTSTATUS Status;
    PVOID MemoryAddress;
    PKPROCESS CallingProcess;
    KAPC_STATE ApcState;
    SIZE_T Size;
 
    UNREFERENCED_PARAMETER(Context);
 
    /* Perform the call in the CSRSS context */
    if (!IntAttachToCSRSS(&CallingProcess, &ApcState))
        return ERROR_INVALID_PARAMETER;
 
    Size = *Length;
    MemoryAddress = (PVOID)0x20000;
 
    Status = ZwAllocateVirtualMemory(NtCurrentProcess(),
                                     &MemoryAddress,
                                     0,
                                     &Size,
                                     MEM_COMMIT,
                                     PAGE_EXECUTE_READWRITE);
    if (!NT_SUCCESS(Status))
    {
        WARN_(VIDEOPRT, "- ZwAllocateVirtualMemory failed\n");
        IntDetachFromCSRSS(CallingProcess, &ApcState);
        return ERROR_NOT_ENOUGH_MEMORY;
    }
 
    if (MemoryAddress > (PVOID)(0x100000 - Size))
    {
        ZwFreeVirtualMemory(NtCurrentProcess(),
                            &MemoryAddress,
                            &Size,
                            MEM_RELEASE);
        WARN_(VIDEOPRT, "- Unacceptable memory allocated\n");
        IntDetachFromCSRSS(CallingProcess, &ApcState);
        return ERROR_NOT_ENOUGH_MEMORY;
    }
 
    IntDetachFromCSRSS(CallingProcess, &ApcState);
 
    *Length = (ULONG)Size;
    *Seg = (USHORT)((ULONG_PTR)MemoryAddress >> 4);
    *Off = (USHORT)((ULONG_PTR)MemoryAddress & 0xF);
 
    return NO_ERROR;
}
#endif // _M_IX86
 
VP_STATUS
NTAPI
IntInt10AllocateBuffer(
    _In_ PVOID Context,
    _Out_ PUSHORT Seg,
    _Out_ PUSHORT Off,
    _Inout_ PULONG Length)
{
    VP_STATUS Status;
 
    TRACE_(VIDEOPRT, "IntInt10AllocateBuffer\n");
 
    Status = INT10(AllocateBuffer)(Context, Seg, Off, Length);
    if (Status == NO_ERROR)
    {
        INFO_(VIDEOPRT, "- Segment: 0x%x\n", *Seg);
        INFO_(VIDEOPRT, "- Offset : 0x%x\n", *Off);
        INFO_(VIDEOPRT, "- Length : 0x%x\n", *Length);
    }
    return Status;
}
 
 
static VP_STATUS
NTAPI
IntInt10FreeBufferEmu(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off)
{
    NTSTATUS Status;
 
    UNREFERENCED_PARAMETER(Context);
 
    Status = x86BiosFreeBuffer(Seg, Off);
    return (NT_SUCCESS(Status) ? NO_ERROR : ERROR_INVALID_PARAMETER);
}
 
#ifdef _M_IX86
static VP_STATUS
NTAPI
IntInt10FreeBufferV86(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off)
{
    NTSTATUS Status;
    PVOID MemoryAddress = (PVOID)((ULONG_PTR)(Seg << 4) | Off);
    PKPROCESS CallingProcess;
    KAPC_STATE ApcState;
    SIZE_T Size = 0;
 
    UNREFERENCED_PARAMETER(Context);
 
    /* Perform the call in the CSRSS context */
    if (!IntAttachToCSRSS(&CallingProcess, &ApcState))
        return ERROR_INVALID_PARAMETER;
 
    Status = ZwFreeVirtualMemory(NtCurrentProcess(),
                                 &MemoryAddress,
                                 &Size,
                                 MEM_RELEASE);
 
    IntDetachFromCSRSS(CallingProcess, &ApcState);
 
    return Status;
}
#endif // _M_IX86
 
VP_STATUS
NTAPI
IntInt10FreeBuffer(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off)
{
    TRACE_(VIDEOPRT, "IntInt10FreeBuffer\n");
    INFO_(VIDEOPRT, "- Segment: 0x%x\n", Seg);
    INFO_(VIDEOPRT, "- Offset : 0x%x\n", Off);
 
    return INT10(FreeBuffer)(Context, Seg, Off);
}
 
 
static VP_STATUS
NTAPI
IntInt10ReadMemoryEmu(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off,
    _Out_writes_bytes_(Length) PVOID Buffer,
    _In_ ULONG Length)
{
    NTSTATUS Status;
 
    UNREFERENCED_PARAMETER(Context);
 
    Status = x86BiosReadMemory(Seg, Off, Buffer, Length);
    return (NT_SUCCESS(Status) ? NO_ERROR : ERROR_INVALID_PARAMETER);
}
 
#ifdef _M_IX86
static VP_STATUS
NTAPI
IntInt10ReadMemoryV86(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off,
    _Out_writes_bytes_(Length) PVOID Buffer,
    _In_ ULONG Length)
{
    PKPROCESS CallingProcess;
    KAPC_STATE ApcState;
 
    UNREFERENCED_PARAMETER(Context);
 
    /* Perform the call in the CSRSS context */
    if (!IntAttachToCSRSS(&CallingProcess, &ApcState))
        return ERROR_INVALID_PARAMETER;
 
    if (IsLowV86Mem(Seg, Off))
        UnprotectLowV86Mem();
    RtlCopyMemory(Buffer, (PVOID)((ULONG_PTR)(Seg << 4) | Off), Length);
    if (IsLowV86Mem(Seg, Off))
        ProtectLowV86Mem();
 
    IntDetachFromCSRSS(CallingProcess, &ApcState);
 
    return NO_ERROR;
}
#endif // _M_IX86
 
VP_STATUS
NTAPI
IntInt10ReadMemory(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off,
    _Out_writes_bytes_(Length) PVOID Buffer,
    _In_ ULONG Length)
{
    TRACE_(VIDEOPRT, "IntInt10ReadMemory\n");
    INFO_(VIDEOPRT, "- Segment: 0x%x\n", Seg);
    INFO_(VIDEOPRT, "- Offset : 0x%x\n", Off);
    INFO_(VIDEOPRT, "- Buffer : 0x%x\n", Buffer);
    INFO_(VIDEOPRT, "- Length : 0x%x\n", Length);
 
    return INT10(ReadMemory)(Context, Seg, Off, Buffer, Length);
}
 
 
static VP_STATUS
NTAPI
IntInt10WriteMemoryEmu(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off,
    _In_reads_bytes_(Length) PVOID Buffer,
    _In_ ULONG Length)
{
    NTSTATUS Status;
 
    UNREFERENCED_PARAMETER(Context);
 
    Status = x86BiosWriteMemory(Seg, Off, Buffer, Length);
    return (NT_SUCCESS(Status) ? NO_ERROR : ERROR_INVALID_PARAMETER);
}
 
#ifdef _M_IX86
static VP_STATUS
NTAPI
IntInt10WriteMemoryV86(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off,
    _In_reads_bytes_(Length) PVOID Buffer,
    _In_ ULONG Length)
{
    PKPROCESS CallingProcess;
    KAPC_STATE ApcState;
 
    UNREFERENCED_PARAMETER(Context);
 
    /* Perform the call in the CSRSS context */
    if (!IntAttachToCSRSS(&CallingProcess, &ApcState))
        return ERROR_INVALID_PARAMETER;
 
    if (IsLowV86Mem(Seg, Off))
        UnprotectLowV86Mem();
    RtlCopyMemory((PVOID)((ULONG_PTR)(Seg << 4) | Off), Buffer, Length);
    if (IsLowV86Mem(Seg, Off))
        ProtectLowV86Mem();
 
    IntDetachFromCSRSS(CallingProcess, &ApcState);
 
    return NO_ERROR;
}
#endif // _M_IX86
 
VP_STATUS
NTAPI
IntInt10WriteMemory(
    _In_ PVOID Context,
    _In_ USHORT Seg,
    _In_ USHORT Off,
    _In_reads_bytes_(Length) PVOID Buffer,
    _In_ ULONG Length)
{
    TRACE_(VIDEOPRT, "IntInt10WriteMemory\n");
    INFO_(VIDEOPRT, "- Segment: 0x%x\n", Seg);
    INFO_(VIDEOPRT, "- Offset : 0x%x\n", Off);
    INFO_(VIDEOPRT, "- Buffer : 0x%x\n", Buffer);
    INFO_(VIDEOPRT, "- Length : 0x%x\n", Length);
 
    return INT10(WriteMemory)(Context, Seg, Off, Buffer, Length);
}
 
 
static VP_STATUS
NTAPI
IntInt10CallBiosEmu(
    _In_ PVOID Context,
    _Inout_ PINT10_BIOS_ARGUMENTS BiosArguments)
{
    X86_BIOS_REGISTERS BiosContext;
    BOOLEAN Success;
 
    UNREFERENCED_PARAMETER(Context);
 
#ifdef _M_IX86
    if (!VDMAddressSpaceInitialized)
    {
        /* There are buggy 3rd-party miniport drivers that invoke the Int10 service
         * in their initialization routine, before the VDM address space has been
         * mapped and Ke386CallBios() can be called. They would therefore hit this
         * ASSERT. Instead, disable it, log an error and bail out. */
        //ASSERT(FALSE);
        ERR_(VIDEOPRT, "Warning: Attempt to call %s before Int10 support is initialized.\n", __FUNCTION__);
        return ERROR_INVALID_PARAMETER;
    }
#endif
 
    /* Clear the context and fill out the BIOS arguments */
    RtlZeroMemory(&BiosContext, sizeof(BiosContext));
    BiosContext.Eax = BiosArguments->Eax;
    BiosContext.Ebx = BiosArguments->Ebx;
    BiosContext.Ecx = BiosArguments->Ecx;
    BiosContext.Edx = BiosArguments->Edx;
    BiosContext.Esi = BiosArguments->Esi;
    BiosContext.Edi = BiosArguments->Edi;
    BiosContext.Ebp = BiosArguments->Ebp;
    BiosContext.SegDs = BiosArguments->SegDs;
    BiosContext.SegEs = BiosArguments->SegEs;
 
    /* Do the ROM BIOS call */
    (void)KeWaitForMutexObject(&VideoPortInt10Mutex,
                               Executive,
                               KernelMode,
                               FALSE,
                               NULL);
 
    Success = x86BiosCall(0x10, &BiosContext);
 
    KeReleaseMutex(&VideoPortInt10Mutex, FALSE);
 
    /* Return the arguments */
    BiosArguments->Eax = BiosContext.Eax;
    BiosArguments->Ebx = BiosContext.Ebx;
    BiosArguments->Ecx = BiosContext.Ecx;
    BiosArguments->Edx = BiosContext.Edx;
    BiosArguments->Esi = BiosContext.Esi;
    BiosArguments->Edi = BiosContext.Edi;
    BiosArguments->Ebp = BiosContext.Ebp;
    BiosArguments->SegDs = (USHORT)BiosContext.SegDs;
    BiosArguments->SegEs = (USHORT)BiosContext.SegEs;
 
    return (Success ? NO_ERROR : ERROR_INVALID_PARAMETER);
}
 
#ifdef _M_IX86
static VP_STATUS
NTAPI
IntInt10CallBiosV86(
    _In_ PVOID Context,
    _Inout_ PINT10_BIOS_ARGUMENTS BiosArguments)
{
    CONTEXT BiosContext;
    NTSTATUS Status;
    PKPROCESS CallingProcess;
    KAPC_STATE ApcState;
 
    UNREFERENCED_PARAMETER(Context);
 
    if (!VDMAddressSpaceInitialized)
    {
        /* There are buggy 3rd-party miniport drivers that invoke the Int10 service
         * in their initialization routine, before the VDM address space has been
         * mapped and Ke386CallBios() can be called. They would therefore hit this
         * ASSERT. Instead, disable it, log an error and bail out. */
        //ASSERT(FALSE);
        ERR_(VIDEOPRT, "Warning: Attempt to call %s before Int10 support is initialized.\n", __FUNCTION__);
        return ERROR_INVALID_PARAMETER;
    }
 
    /* Clear the context and fill out the BIOS arguments */
    RtlZeroMemory(&BiosContext, sizeof(BiosContext));
    BiosContext.Eax = BiosArguments->Eax;
    BiosContext.Ebx = BiosArguments->Ebx;
    BiosContext.Ecx = BiosArguments->Ecx;
    BiosContext.Edx = BiosArguments->Edx;
    BiosContext.Esi = BiosArguments->Esi;
    BiosContext.Edi = BiosArguments->Edi;
    BiosContext.Ebp = BiosArguments->Ebp;
    BiosContext.SegDs = BiosArguments->SegDs;
    BiosContext.SegEs = BiosArguments->SegEs;
 
    /* Perform the call in the CSRSS context */
    if (!IntAttachToCSRSS(&CallingProcess, &ApcState))
        return ERROR_INVALID_PARAMETER;
 
    /* Do the ROM BIOS call */
    (void)KeWaitForMutexObject(&VideoPortInt10Mutex,
                               Executive,
                               KernelMode,
                               FALSE,
                               NULL);
 
    /* The kernel needs access here */
    UnprotectLowV86Mem();
 
    /* Invoke the V86 monitor under SEH, as it can raise exceptions */
    _SEH2_TRY
    {
        Status = Ke386CallBios(0x10, &BiosContext);
    }
    _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
    {
        Status = _SEH2_GetExceptionCode();
    }
    _SEH2_END;
 
    ProtectLowV86Mem();
 
    KeReleaseMutex(&VideoPortInt10Mutex, FALSE);
 
    IntDetachFromCSRSS(CallingProcess, &ApcState);
 
    /* Return the arguments */
    BiosArguments->Eax = BiosContext.Eax;
    BiosArguments->Ebx = BiosContext.Ebx;
    BiosArguments->Ecx = BiosContext.Ecx;
    BiosArguments->Edx = BiosContext.Edx;
    BiosArguments->Esi = BiosContext.Esi;
    BiosArguments->Edi = BiosContext.Edi;
    BiosArguments->Ebp = BiosContext.Ebp;
    BiosArguments->SegDs = (USHORT)BiosContext.SegDs;
    BiosArguments->SegEs = (USHORT)BiosContext.SegEs;
 
    return (NT_SUCCESS(Status) ? NO_ERROR : ERROR_INVALID_PARAMETER);
}
#endif // _M_IX86
 
VP_STATUS
NTAPI
IntInt10CallBios(
    _In_ PVOID Context,
    _Inout_ PINT10_BIOS_ARGUMENTS BiosArguments)
{
    return INT10(CallBios)(Context, BiosArguments);
}
 
 
#ifdef _M_IX86
static const INT10_INTERFACE Int10IFace[2] =
{ { IntInt10AllocateBufferEmu,
    IntInt10FreeBufferEmu,
    IntInt10ReadMemoryEmu,
    IntInt10WriteMemoryEmu,
    IntInt10CallBiosEmu }
  ,
  { IntInt10AllocateBufferV86,
    IntInt10FreeBufferV86,
    IntInt10ReadMemoryV86,
    IntInt10WriteMemoryV86,
    IntInt10CallBiosV86 }
};
static const INT10_INTERFACE *Int10Vtbl = &Int10IFace[0];
#endif
 
 
/* PRIVATE FUNCTIONS **********************************************************/
 
NTSTATUS
IntInitializeInt10(VOID)
{
    static BOOLEAN FirstInitialization = FALSE;
 
    if (!FirstInitialization)
    {
        FirstInitialization = TRUE;
#ifdef _M_IX86
        /* Initialize the x86 emulator if necessary, otherwise fall back to V86 mode */
        if (!VideoPortDisableX86Emulator)
        {
            /* Use the emulation routines */
            //Int10Vtbl = &Int10IFace[0];
            if (IntInitializeX86Emu())
                return STATUS_SUCCESS;
            DPRINT1("Could not initialize the x86 emulator; falling back to V86 mode\n");
            VideoPortDisableX86Emulator = TRUE;
        }
 
        /* Fall back to the V86 routines */
        Int10Vtbl = &Int10IFace[1];
        return STATUS_SUCCESS;
#else
        /* Initialize the x86 emulator */
        return (IntInitializeX86Emu() ? STATUS_SUCCESS : STATUS_NOT_SUPPORTED);
#endif
    }
 
    /* We should only do that for CSRSS */
    ASSERT(PsGetCurrentProcess() == (PEPROCESS)CsrProcess);
#ifdef _M_IX86
    return IntInitializeVideoAddressSpace();
#else
    return STATUS_SUCCESS;
#endif
}
 
 
/* PUBLIC FUNCTIONS ***********************************************************/
 
/*
 * @implemented
 */
VP_STATUS
NTAPI
VideoPortInt10(
    IN PVOID HwDeviceExtension,
    IN PVIDEO_X86_BIOS_ARGUMENTS BiosArguments)
{
    VP_STATUS Status;
    INT10_BIOS_ARGUMENTS Int10BiosArguments;
 
    /* Copy arguments to other format */
    RtlCopyMemory(&Int10BiosArguments, BiosArguments, sizeof(*BiosArguments));
    Int10BiosArguments.SegDs = 0;
    Int10BiosArguments.SegEs = 0;
 
    /* Do the BIOS call */
    Status = IntInt10CallBios(NULL, &Int10BiosArguments);
 
    /* Copy results back */
    RtlCopyMemory(BiosArguments, &Int10BiosArguments, sizeof(*BiosArguments));
 
    return Status;
}