OvmfPkg/QemuVideoDxe/VbeShim.c

   1 /** @file
   2   Install a fake VGABIOS service handler (real mode Int10h) for the buggy
   3   Windows 2008 R2 SP1 UEFI guest.
   4
   5   The handler is never meant to be directly executed by a VCPU; it's there for
   6   the internal real mode emulator of Windows 2008 R2 SP1.
   7
   8   The code is based on Ralf Brown's Interrupt List:
   9   <http://www.cs.cmu.edu/~ralf/files.html>
  10   <http://www.ctyme.com/rbrown.htm>
  11
  12   Copyright (C) 2014, Red Hat, Inc.
  13   Copyright (c) 2013 - 2014, Intel Corporation. All rights reserved.<BR>
  14
  15   This program and the accompanying materials are licensed and made available
  16   under the terms and conditions of the BSD License which accompanies this
  17   distribution. The full text of the license may be found at
  18   http://opensource.org/licenses/bsd-license.php
  19
  20   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
  21   WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  22 **/
  23
  24 #include <IndustryStandard/LegacyVgaBios.h>
  25 #include <Library/DebugLib.h>
  26 #include <Library/PciLib.h>
  27 #include <Library/PrintLib.h>
  28
  29 #include "Qemu.h"
  30 #include "VbeShim.h"
  31
  32 #pragma pack (1)
  33 typedef struct {
  34   UINT16 Offset;
  35   UINT16 Segment;
  36 } IVT_ENTRY;
  37 #pragma pack ()
  38
  39 //
  40 // This string is displayed by Windows 2008 R2 SP1 in the Screen Resolution,
  41 // Advanced Settings dialog. It should be short.
  42 //
  43 STATIC CONST CHAR8 mProductRevision[] = "OVMF Int10h (fake)";
  44
  45 /**
  46   Install the VBE Info and VBE Mode Info structures, and the VBE service
  47   handler routine in the C segment. Point the real-mode Int10h interrupt vector
  48   to the handler. The only advertised mode is 1024x768x32.
  49
  50   @param[in] CardName         Name of the video card to be exposed in the
  51                               Product Name field of the VBE Info structure. The
  52                               parameter must originate from a
  53                               QEMU_VIDEO_CARD.Name field.
  54   @param[in] FrameBufferBase  Guest-physical base address of the video card's
  55                               frame buffer.
  56 **/
  57 VOID
  58 InstallVbeShim (
  59   IN CONST CHAR16         *CardName,
  60   IN EFI_PHYSICAL_ADDRESS FrameBufferBase
  61   )
  62 {
  63   EFI_PHYSICAL_ADDRESS Segment0, SegmentC, SegmentF;
  64   UINTN                Segment0Pages;
  65   IVT_ENTRY            *Int0x10;
  66   EFI_STATUS           Segment0AllocationStatus;
  67   UINTN                Pam1Address;
  68   UINT8                Pam1;
  69   UINTN                SegmentCPages;
  70   VBE_INFO             *VbeInfoFull;
  71   VBE_INFO_BASE        *VbeInfo;
  72   UINT8                *Ptr;
  73   UINTN                Printed;
  74   VBE_MODE_INFO        *VbeModeInfo;
  75
  76   Segment0 = 0x00000;
  77   SegmentC = 0xC0000;
  78   SegmentF = 0xF0000;
  79
  80   //
  81   // Attempt to cover the real mode IVT with an allocation. This is a UEFI
  82   // driver, hence the arch protocols have been installed previously. Among
  83   // those, the CPU arch protocol has configured the IDT, so we can overwrite
  84   // the IVT used in real mode.
  85   //
  86   // The allocation request may fail, eg. if LegacyBiosDxe has already run.
  87   //
  88   Segment0Pages = 1;
  89   Int0x10       = (IVT_ENTRY *)(UINTN)Segment0 + 0x10;
  90   Segment0AllocationStatus = gBS->AllocatePages (
  91                                     AllocateAddress,
  92                                     EfiBootServicesCode,
  93                                     Segment0Pages,
  94                                     &Segment0
  95                                     );
  96
  97   if (EFI_ERROR (Segment0AllocationStatus)) {
  98     EFI_PHYSICAL_ADDRESS Handler;
  99
 100     //
 101     // Check if a video BIOS handler has been installed previously -- we
 102     // shouldn't override a real video BIOS with our shim, nor our own shim if
 103     // it's already present.
 104     //
 105     Handler = (Int0x10->Segment << 4) + Int0x10->Offset;
 106     if (Handler >= SegmentC && Handler < SegmentF) {
 107       DEBUG ((EFI_D_INFO, "%a: Video BIOS handler found at %04x:%04x\n",
 108         __FUNCTION__, Int0x10->Segment, Int0x10->Offset));
 109       return;
 110     }
 111
 112     //
 113     // Otherwise we'll overwrite the Int10h vector, even though we may not own
 114     // the page at zero.
 115     //
 116     DEBUG ((
 117       DEBUG_INFO,
 118       "%a: failed to allocate page at zero: %r\n",
 119       __FUNCTION__,
 120       Segment0AllocationStatus
 121       ));
 122   } else {
 123     //
 124     // We managed to allocate the page at zero. SVN r14218 guarantees that it
 125     // is NUL-filled.
 126     //
 127     ASSERT (Int0x10->Segment == 0x0000);
 128     ASSERT (Int0x10->Offset  == 0x0000);
 129   }
 130
 131   //
 132   // Put the shim in place first.
 133   //
 134   Pam1Address = PCI_LIB_ADDRESS (0, 0, 0, 0x5A);
 135   //
 136   // low nibble covers 0xC0000 to 0xC3FFF
 137   // high nibble covers 0xC4000 to 0xC7FFF
 138   // bit1 in each nibble is Write Enable
 139   // bit0 in each nibble is Read Enable
 140   //
 141   Pam1 = PciRead8 (Pam1Address);
 142   PciWrite8 (Pam1Address, Pam1 | (BIT1 | BIT0));
 143
 144   //
 145   // We never added memory space during PEI or DXE for the C segment, so we
 146   // don't need to (and can't) allocate from there. Also, guest operating
 147   // systems will see a hole in the UEFI memory map there.
 148   //
 149   SegmentCPages = 4;
 150
 151   ASSERT (sizeof mVbeShim <= EFI_PAGES_TO_SIZE (SegmentCPages));
 152   CopyMem ((VOID *)(UINTN)SegmentC, mVbeShim, sizeof mVbeShim);
 153
 154   //
 155   // Fill in the VBE INFO structure.
 156   //
 157   VbeInfoFull = (VBE_INFO *)(UINTN)SegmentC;
 158   VbeInfo     = &VbeInfoFull->Base;
 159   Ptr         = VbeInfoFull->Buffer;
 160
 161   CopyMem (VbeInfo->Signature, "VESA", 4);
 162   VbeInfo->VesaVersion = 0x0300;
 163
 164   VbeInfo->OemNameAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
 165   CopyMem (Ptr, "QEMU", 5);
 166   Ptr += 5;
 167
 168   VbeInfo->Capabilities = BIT0; // DAC can be switched into 8-bit mode
 169
 170   VbeInfo->ModeListAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
 171   *(UINT16*)Ptr = 0x00f1; // mode number
 172   Ptr += 2;
 173   *(UINT16*)Ptr = 0xFFFF; // mode list terminator
 174   Ptr += 2;
 175
 176   VbeInfo->VideoMem64K = (UINT16)((1024 * 768 * 4 + 65535) / 65536);
 177   VbeInfo->OemSoftwareVersion = 0x0000;
 178
 179   VbeInfo->VendorNameAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
 180   CopyMem (Ptr, "OVMF", 5);
 181   Ptr += 5;
 182
 183   VbeInfo->ProductNameAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
 184   Printed = AsciiSPrint ((CHAR8 *)Ptr,
 185               sizeof VbeInfoFull->Buffer - (Ptr - VbeInfoFull->Buffer), "%s",
 186               CardName);
 187   Ptr += Printed + 1;
 188
 189   VbeInfo->ProductRevAddress = (UINT32)SegmentC << 12 | (UINT16)(UINTN)Ptr;
 190   CopyMem (Ptr, mProductRevision, sizeof mProductRevision);
 191   Ptr += sizeof mProductRevision;
 192
 193   ASSERT (sizeof VbeInfoFull->Buffer >= Ptr - VbeInfoFull->Buffer);
 194   ZeroMem (Ptr, sizeof VbeInfoFull->Buffer - (Ptr - VbeInfoFull->Buffer));
 195
 196   //
 197   // Fil in the VBE MODE INFO structure.
 198   //
 199   VbeModeInfo = (VBE_MODE_INFO *)(VbeInfoFull + 1);
 200
 201   //
 202   // bit0: mode supported by present hardware configuration
 203   // bit1: optional information available (must be =1 for VBE v1.2+)
 204   // bit3: set if color, clear if monochrome
 205   // bit4: set if graphics mode, clear if text mode
 206   // bit5: mode is not VGA-compatible
 207   // bit7: linear framebuffer mode supported
 208   //
 209   VbeModeInfo->ModeAttr = BIT7 | BIT5 | BIT4 | BIT3 | BIT1 | BIT0;
 210
 211   //
 212   // bit0: exists
 213   // bit1: bit1: readable
 214   // bit2: writeable
 215   //
 216   VbeModeInfo->WindowAAttr              = BIT2 | BIT1 | BIT0;
 217
 218   VbeModeInfo->WindowBAttr              = 0x00;
 219   VbeModeInfo->WindowGranularityKB      = 0x0040;
 220   VbeModeInfo->WindowSizeKB             = 0x0040;
 221   VbeModeInfo->WindowAStartSegment      = 0xA000;
 222   VbeModeInfo->WindowBStartSegment      = 0x0000;
 223   VbeModeInfo->WindowPositioningAddress = 0x0000;
 224   VbeModeInfo->BytesPerScanLine         = 1024 * 4;
 225
 226   VbeModeInfo->Width                = 1024;
 227   VbeModeInfo->Height               = 768;
 228   VbeModeInfo->CharCellWidth        = 8;
 229   VbeModeInfo->CharCellHeight       = 16;
 230   VbeModeInfo->NumPlanes            = 1;
 231   VbeModeInfo->BitsPerPixel         = 32;
 232   VbeModeInfo->NumBanks             = 1;
 233   VbeModeInfo->MemoryModel          = 6; // direct color
 234   VbeModeInfo->BankSizeKB           = 0;
 235   VbeModeInfo->NumImagePagesLessOne = 0;
 236   VbeModeInfo->Vbe3                 = 0x01;
 237
 238   VbeModeInfo->RedMaskSize      = 8;
 239   VbeModeInfo->RedMaskPos       = 16;
 240   VbeModeInfo->GreenMaskSize    = 8;
 241   VbeModeInfo->GreenMaskPos     = 8;
 242   VbeModeInfo->BlueMaskSize     = 8;
 243   VbeModeInfo->BlueMaskPos      = 0;
 244   VbeModeInfo->ReservedMaskSize = 8;
 245   VbeModeInfo->ReservedMaskPos  = 24;
 246
 247   //
 248   // bit1: Bytes in reserved field may be used by application
 249   //
 250   VbeModeInfo->DirectColorModeInfo = BIT1;
 251
 252   VbeModeInfo->LfbAddress       = (UINT32)FrameBufferBase;
 253   VbeModeInfo->OffScreenAddress = 0;
 254   VbeModeInfo->OffScreenSizeKB  = 0;
 255
 256   VbeModeInfo->BytesPerScanLineLinear = 1024 * 4;
 257   VbeModeInfo->NumImagesLessOneBanked = 0;
 258   VbeModeInfo->NumImagesLessOneLinear = 0;
 259   VbeModeInfo->RedMaskSizeLinear      = 8;
 260   VbeModeInfo->RedMaskPosLinear       = 16;
 261   VbeModeInfo->GreenMaskSizeLinear    = 8;
 262   VbeModeInfo->GreenMaskPosLinear     = 8;
 263   VbeModeInfo->BlueMaskSizeLinear     = 8;
 264   VbeModeInfo->BlueMaskPosLinear      = 0;
 265   VbeModeInfo->ReservedMaskSizeLinear = 8;
 266   VbeModeInfo->ReservedMaskPosLinear  = 24;
 267   VbeModeInfo->MaxPixelClockHz        = 0;
 268
 269   ZeroMem (VbeModeInfo->Reserved, sizeof VbeModeInfo->Reserved);
 270
 271   //
 272   // Clear Write Enable (bit1), keep Read Enable (bit0) set
 273   //
 274   PciWrite8 (Pam1Address, (Pam1 & ~BIT1) | BIT0);
 275
 276   //
 277   // Second, point the Int10h vector at the shim.
 278   //
 279   Int0x10->Segment = (UINT16) ((UINT32)SegmentC >> 4);
 280   Int0x10->Offset  = (UINT16) ((UINTN) (VbeModeInfo + 1) - SegmentC);
 281
 282   DEBUG ((EFI_D_INFO, "%a: VBE shim installed\n", __FUNCTION__));
 283 }