diff options
Diffstat (limited to 'OvmfPkg/Bhyve/BhyveRfbDxe/VbeShim.c')
| -rw-r--r-- | OvmfPkg/Bhyve/BhyveRfbDxe/VbeShim.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/OvmfPkg/Bhyve/BhyveRfbDxe/VbeShim.c b/OvmfPkg/Bhyve/BhyveRfbDxe/VbeShim.c new file mode 100644 index 0000000000..740b966794 --- /dev/null +++ b/OvmfPkg/Bhyve/BhyveRfbDxe/VbeShim.c @@ -0,0 +1,259 @@ +/** @file
+ Install a fake VGABIOS service handler (real mode Int10h) for the buggy
+ Windows 2008 R2 SP1 UEFI guest.
+
+ The handler is never meant to be directly executed by a VCPU; it's there for
+ the internal real mode emulator of Windows 2008 R2 SP1.
+
+ The code is based on Ralf Brown's Interrupt List:
+ <http://www.cs.cmu.edu/~ralf/files.html>
+ <http://www.ctyme.com/rbrown.htm>
+
+ Copyright (C) 2020, Rebecca Cran <rebecca@bsdio.com>
+ Copyright (C) 2015, Nahanni Systems, Inc.
+ Copyright (C) 2014, Red Hat, Inc.
+ Copyright (c) 2013 - 2014, Intel Corporation. All rights reserved.<BR>
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <IndustryStandard/LegacyVgaBios.h>
+#include <Library/DebugLib.h>
+#include <Library/PciLib.h>
+#include <Library/PrintLib.h>
+
+#include "Gop.h"
+#include "VbeShim.h"
+
+#pragma pack (1)
+typedef struct {
+ UINT16 Offset;
+ UINT16 Segment;
+} IVT_ENTRY;
+#pragma pack ()
+
+//
+// This string is displayed by Windows 2008 R2 SP1 in the Screen Resolution,
+// Advanced Settings dialog. It should be short.
+//
+STATIC CONST CHAR8 mProductRevision[] = "2.0";
+
+#define NUM_VBE_MODES 3
+STATIC CONST UINT16 vbeModeIds[] = {
+ 0x13f, // 640x480x32
+ 0x140, // 800x600x32
+ 0x141 // 1024x768x32
+};
+
+// Modes can be toggled with bit-0
+#define VBE_MODE_ENABLED 0x00BB
+#define VBE_MODE_DISABLED 0x00BA
+
+STATIC VBE2_MODE_INFO vbeModes[] = {
+ { // 0x13f 640x480x32
+
+ // ModeAttr - BytesPerScanLine
+ VBE_MODE_DISABLED, 0x07, 0x00, 0x40, 0x40, 0xA000, 0x00, 0x0000, 640*4,
+ // Width, Height..., Vbe3
+ 640, 480, 16, 8, 1, 32, 1, 0x06, 0, 0, 1,
+ // Masks
+ 0x08, 0x10, 0x08, 0x08, 0x08, 0x00, 0x08, 0x18, 0x00,
+ // Framebuffer
+ 0xdeadbeef, 0x0000, 0x0000
+ },
+ { // 0x140 800x600x32
+
+ // ModeAttr - BytesPerScanLine
+ VBE_MODE_DISABLED, 0x07, 0x00, 0x40, 0x40, 0xA000, 0x00, 0x0000, 800*4,
+ // Width, Height..., Vbe3
+ 800, 600, 16, 8, 1, 32, 1, 0x06, 0, 0, 1,
+ // Masks
+ 0x08, 0x10, 0x08, 0x08, 0x08, 0x00, 0x08, 0x18, 0x00,
+ // Framebuffer
+ 0xdeadbeef, 0x0000, 0x0000
+ },
+ { // 0x141 1024x768x32
+
+ // ModeAttr - BytesPerScanLine
+ VBE_MODE_ENABLED, 0x07, 0x00, 0x40, 0x40, 0xA000, 0x00, 0x0000, 1024*4,
+ // Width, Height..., Vbe3
+ 1024, 768, 16, 8, 1, 32, 1, 0x06, 0, 0, 1,
+ // Masks
+ 0x08, 0x10, 0x08, 0x08, 0x08, 0x00, 0x08, 0x18, 0x00,
+ // Framebuffer
+ 0xdeadbeef, 0x0000, 0x0000
+ }
+};
+
+/**
+ Install the VBE Info and VBE Mode Info structures, and the VBE service
+ handler routine in the C segment. Point the real-mode Int10h interrupt vector
+ to the handler. The only advertised mode is 1024x768x32.
+
+ @param[in] CardName Name of the video card to be exposed in the
+ Product Name field of the VBE Info structure.
+ @param[in] FrameBufferBase Guest-physical base address of the video card's
+ frame buffer.
+**/
+VOID
+InstallVbeShim (
+ IN CONST CHAR16 *CardName,
+ IN EFI_PHYSICAL_ADDRESS FrameBufferBase
+ )
+{
+ EFI_PHYSICAL_ADDRESS Segment0, SegmentC, SegmentF;
+ UINTN Segment0Pages;
+ IVT_ENTRY *Int0x10;
+ EFI_STATUS Status;
+ UINTN Pam1Address;
+ UINT8 Pam1;
+ UINTN SegmentCPages;
+ VBE_INFO *VbeInfoFull;
+ VBE_INFO_BASE *VbeInfo;
+ UINT8 *Ptr;
+ UINTN Printed;
+ VBE_MODE_INFO *VbeModeInfo;
+ UINTN i;
+
+ Segment0 = 0x00000;
+ SegmentC = 0xC0000;
+ SegmentF = 0xF0000;
+
+ //
+ // Attempt to cover the real mode IVT with an allocation. This is a UEFI
+ // driver, hence the arch protocols have been installed previously. Among
+ // those, the CPU arch protocol has configured the IDT, so we can overwrite
+ // the IVT used in real mode.
+ //
+ // The allocation request may fail, eg. if LegacyBiosDxe has already run.
+ //
+ Segment0Pages = 1;
+ Int0x10 = (IVT_ENTRY *)(UINTN)Segment0 + 0x10;
+ Status = gBS->AllocatePages (AllocateAddress, EfiBootServicesCode,
+ Segment0Pages, &Segment0);
+
+ if (EFI_ERROR (Status)) {
+ EFI_PHYSICAL_ADDRESS Handler;
+
+ //
+ // Check if a video BIOS handler has been installed previously -- we
+ // shouldn't override a real video BIOS with our shim, nor our own shim if
+ // it's already present.
+ //
+ Handler = (Int0x10->Segment << 4) + Int0x10->Offset;
+ if (Handler >= SegmentC && Handler < SegmentF) {
+ DEBUG ((DEBUG_VERBOSE, "%a: Video BIOS handler found at %04x:%04x\n",
+ __FUNCTION__, Int0x10->Segment, Int0x10->Offset));
+ return;
+ }
+
+ //
+ // Otherwise we'll overwrite the Int10h vector, even though we may not own
+ // the page at zero.
+ //
+ DEBUG ((DEBUG_VERBOSE, "%a: failed to allocate page at zero: %r\n",
+ __FUNCTION__, Status));
+ } else {
+ //
+ // We managed to allocate the page at zero. SVN r14218 guarantees that it
+ // is NUL-filled.
+ //
+ ASSERT (Int0x10->Segment == 0x0000);
+ ASSERT (Int0x10->Offset == 0x0000);
+ }
+
+ //
+ // Put the shim in place first.
+ //
+ Pam1Address = PCI_LIB_ADDRESS (0, 0, 0, 0x5A);
+ //
+ // low nibble covers 0xC0000 to 0xC3FFF
+ // high nibble covers 0xC4000 to 0xC7FFF
+ // bit1 in each nibble is Write Enable
+ // bit0 in each nibble is Read Enable
+ //
+ Pam1 = PciRead8 (Pam1Address);
+ PciWrite8 (Pam1Address, Pam1 | (BIT1 | BIT0));
+
+ //
+ // We never added memory space durig PEI or DXE for the C segment, so we
+ // don't need to (and can't) allocate from there. Also, guest operating
+ // systems will see a hole in the UEFI memory map there.
+ //
+ SegmentCPages = 4;
+
+ ASSERT (sizeof mVbeShim <= EFI_PAGES_TO_SIZE (SegmentCPages));
+ CopyMem ((VOID *)(UINTN)SegmentC, mVbeShim, sizeof mVbeShim);
+
+ //
+ // Fill in the VBE INFO structure.
+ //
+ VbeInfoFull = (VBE_INFO *)(UINTN)SegmentC;
+ VbeInfo = &VbeInfoFull->Base;
+ Ptr = VbeInfoFull->Buffer;
+
+ CopyMem (VbeInfo->Signature, "VESA", 4);
+ VbeInfo->VesaVersion = 0x0200;
+
+ VbeInfo->OemNameAddress = (UINT32)SegmentC << 12 | (UINT16)((UINTN)Ptr-SegmentC);
+ CopyMem (Ptr, "FBSD", 5);
+ Ptr += 5;
+
+ VbeInfo->Capabilities = BIT1 | BIT0; // DAC can be switched into 8-bit mode
+
+ VbeInfo->ModeListAddress = (UINT32)SegmentC << 12 | (UINT16)((UINTN)Ptr-SegmentC);
+ for (i = 0; i < NUM_VBE_MODES; i ++) {
+ *(UINT16*)Ptr = vbeModeIds[i]; // mode number
+ Ptr += 2;
+ }
+ *(UINT16*)Ptr = 0xFFFF; // mode list terminator
+ Ptr += 2;
+
+ VbeInfo->VideoMem64K = (UINT16)((1024 * 768 * 4 + 65535) / 65536);
+ VbeInfo->OemSoftwareVersion = 0x0200;
+
+ VbeInfo->VendorNameAddress = (UINT32)SegmentC << 12 | (UINT16)((UINTN)Ptr-SegmentC);
+ CopyMem (Ptr, "FBSD", 5);
+ Ptr += 5;
+
+ VbeInfo->ProductNameAddress = (UINT32)SegmentC << 12 | (UINT16)((UINTN)Ptr-SegmentC);
+ Printed = AsciiSPrint ((CHAR8 *)Ptr,
+ sizeof VbeInfoFull->Buffer - (Ptr - VbeInfoFull->Buffer), "%s",
+ CardName);
+ Ptr += Printed + 1;
+
+ VbeInfo->ProductRevAddress = (UINT32)SegmentC << 12 | (UINT16)((UINTN)Ptr-SegmentC);
+ CopyMem (Ptr, mProductRevision, sizeof mProductRevision);
+ Ptr += sizeof mProductRevision;
+
+ ASSERT (sizeof VbeInfoFull->Buffer >= Ptr - VbeInfoFull->Buffer);
+ ZeroMem (Ptr, sizeof VbeInfoFull->Buffer - (Ptr - VbeInfoFull->Buffer));
+
+ //
+ // Fill in the VBE MODE INFO structure list
+ //
+ VbeModeInfo = (VBE_MODE_INFO *)(VbeInfoFull + 1);
+ Ptr = (UINT8 *)VbeModeInfo;
+ for (i = 0; i < NUM_VBE_MODES; i++) {
+ vbeModes[i].LfbAddress = (UINT32)FrameBufferBase;
+ CopyMem (Ptr, &vbeModes[i], 0x32);
+ Ptr += 0x32;
+ }
+
+ ZeroMem (Ptr, 56); // Clear remaining bytes
+
+ //
+ // Clear Write Enable (bit1), keep Read Enable (bit0) set
+ //
+ PciWrite8 (Pam1Address, (Pam1 & ~BIT1) | BIT0);
+
+ //
+ // Second, point the Int10h vector at the shim.
+ //
+ Int0x10->Segment = (UINT16) ((UINT32)SegmentC >> 4);
+ Int0x10->Offset = (UINT16) ((UINTN) (VbeModeInfo + 1) - SegmentC);
+
+ DEBUG ((DEBUG_INFO, "%a: VBE shim installed to %x:%x\n",
+ __FUNCTION__, Int0x10->Segment, Int0x10->Offset));
+}
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