OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c

   1 /**  @file
   2   Generic implementation of QemuLoadImageLib library class interface.
   3
   4   Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
   5
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7 **/
   8
   9 #include <Uefi.h>
  10
  11 #include <Base.h>
  12 #include <Guid/QemuKernelLoaderFsMedia.h>
  13 #include <Library/DebugLib.h>
  14 #include <Library/MemoryAllocationLib.h>
  15 #include <Library/PrintLib.h>
  16 #include <Library/QemuFwCfgLib.h>
  17 #include <Library/QemuLoadImageLib.h>
  18 #include <Library/UefiBootServicesTableLib.h>
  19 #include <Protocol/DevicePath.h>
  20 #include <Protocol/LoadedImage.h>
  21
  22 #pragma pack (1)
  23 typedef struct {
  24   EFI_DEVICE_PATH_PROTOCOL  FilePathHeader;
  25   CHAR16                    FilePath[ARRAY_SIZE (L"kernel")];
  26 } KERNEL_FILE_DEVPATH;
  27
  28 typedef struct {
  29   VENDOR_DEVICE_PATH        VenMediaNode;
  30   KERNEL_FILE_DEVPATH       FileNode;
  31   EFI_DEVICE_PATH_PROTOCOL  EndNode;
  32 } KERNEL_VENMEDIA_FILE_DEVPATH;
  33 #pragma pack ()
  34
  35 STATIC CONST KERNEL_VENMEDIA_FILE_DEVPATH mKernelDevicePath = {
  36   {
  37     {
  38       MEDIA_DEVICE_PATH, MEDIA_VENDOR_DP,
  39       { sizeof (VENDOR_DEVICE_PATH) }
  40     },
  41     QEMU_KERNEL_LOADER_FS_MEDIA_GUID
  42   }, {
  43     {
  44       MEDIA_DEVICE_PATH, MEDIA_FILEPATH_DP,
  45       { sizeof (KERNEL_FILE_DEVPATH) }
  46     },
  47     L"kernel",
  48   }, {
  49     END_DEVICE_PATH_TYPE, END_ENTIRE_DEVICE_PATH_SUBTYPE,
  50     { sizeof (EFI_DEVICE_PATH_PROTOCOL) }
  51   }
  52 };
  53
  54 /**
  55   Download the kernel, the initial ramdisk, and the kernel command line from
  56   QEMU's fw_cfg. The kernel will be instructed via its command line to load
  57   the initrd from the same Simple FileSystem where the kernel was loaded from.
  58
  59   @param[out] ImageHandle       The image handle that was allocated for
  60                                 loading the image
  61
  62   @retval EFI_SUCCESS           The image was loaded successfully.
  63   @retval EFI_NOT_FOUND         Kernel image was not found.
  64   @retval EFI_OUT_OF_RESOURCES  Memory allocation failed.
  65   @retval EFI_PROTOCOL_ERROR    Unterminated kernel command line.
  66   @retval EFI_ACCESS_DENIED     The underlying LoadImage boot service call
  67                                 returned EFI_SECURITY_VIOLATION, and the image
  68                                 was unloaded again.
  69
  70   @return                       Error codes from any of the underlying
  71                                 functions.
  72 **/
  73 EFI_STATUS
  74 EFIAPI
  75 QemuLoadKernelImage (
  76   OUT EFI_HANDLE                  *ImageHandle
  77   )
  78 {
  79   EFI_STATUS                Status;
  80   EFI_HANDLE                KernelImageHandle;
  81   EFI_LOADED_IMAGE_PROTOCOL *KernelLoadedImage;
  82   UINTN                     CommandLineSize;
  83   CHAR8                     *CommandLine;
  84   UINTN                     InitrdSize;
  85
  86   //
  87   // Load the image. This should call back into the QEMU EFI loader file system.
  88   //
  89   Status = gBS->LoadImage (
  90                   FALSE,                    // BootPolicy: exact match required
  91                   gImageHandle,             // ParentImageHandle
  92                   (EFI_DEVICE_PATH_PROTOCOL *)&mKernelDevicePath,
  93                   NULL,                     // SourceBuffer
  94                   0,                        // SourceSize
  95                   &KernelImageHandle
  96                   );
  97   switch (Status) {
  98   case EFI_SUCCESS:
  99     break;
 100
 101   case EFI_SECURITY_VIOLATION:
 102     //
 103     // In this case, the image was loaded but failed to authenticate.
 104     //
 105     Status = EFI_ACCESS_DENIED;
 106     goto UnloadImage;
 107
 108   default:
 109     DEBUG ((DEBUG_ERROR, "%a: LoadImage(): %r\n", __FUNCTION__, Status));
 110     return Status;
 111   }
 112
 113   //
 114   // Construct the kernel command line.
 115   //
 116   Status = gBS->OpenProtocol (
 117                   KernelImageHandle,
 118                   &gEfiLoadedImageProtocolGuid,
 119                   (VOID **)&KernelLoadedImage,
 120                   gImageHandle,                  // AgentHandle
 121                   NULL,                          // ControllerHandle
 122                   EFI_OPEN_PROTOCOL_GET_PROTOCOL
 123                   );
 124   ASSERT_EFI_ERROR (Status);
 125
 126   QemuFwCfgSelectItem (QemuFwCfgItemCommandLineSize);
 127   CommandLineSize = (UINTN)QemuFwCfgRead32 ();
 128
 129   if (CommandLineSize == 0) {
 130     KernelLoadedImage->LoadOptionsSize = 0;
 131   } else {
 132     CommandLine = AllocatePool (CommandLineSize);
 133     if (CommandLine == NULL) {
 134       Status = EFI_OUT_OF_RESOURCES;
 135       goto UnloadImage;
 136     }
 137
 138     QemuFwCfgSelectItem (QemuFwCfgItemCommandLineData);
 139     QemuFwCfgReadBytes (CommandLineSize, CommandLine);
 140
 141     //
 142     // Verify NUL-termination of the command line.
 143     //
 144     if (CommandLine[CommandLineSize - 1] != '\0') {
 145       DEBUG ((DEBUG_ERROR, "%a: kernel command line is not NUL-terminated\n",
 146         __FUNCTION__));
 147       Status = EFI_PROTOCOL_ERROR;
 148       goto FreeCommandLine;
 149     }
 150
 151     //
 152     // Drop the terminating NUL, convert to UTF-16.
 153     //
 154     KernelLoadedImage->LoadOptionsSize = (UINT32)((CommandLineSize - 1) * 2);
 155   }
 156
 157   QemuFwCfgSelectItem (QemuFwCfgItemInitrdSize);
 158   InitrdSize = (UINTN)QemuFwCfgRead32 ();
 159
 160   if (InitrdSize > 0) {
 161     //
 162     // Append ' initrd=initrd' in UTF-16.
 163     //
 164     KernelLoadedImage->LoadOptionsSize += sizeof (L" initrd=initrd") - 2;
 165   }
 166
 167   if (KernelLoadedImage->LoadOptionsSize == 0) {
 168     KernelLoadedImage->LoadOptions = NULL;
 169   } else {
 170     //
 171     // NUL-terminate in UTF-16.
 172     //
 173     KernelLoadedImage->LoadOptionsSize += 2;
 174
 175     KernelLoadedImage->LoadOptions = AllocatePool (
 176                                        KernelLoadedImage->LoadOptionsSize);
 177     if (KernelLoadedImage->LoadOptions == NULL) {
 178       KernelLoadedImage->LoadOptionsSize = 0;
 179       Status = EFI_OUT_OF_RESOURCES;
 180       goto FreeCommandLine;
 181     }
 182
 183     UnicodeSPrintAsciiFormat (
 184       KernelLoadedImage->LoadOptions,
 185       KernelLoadedImage->LoadOptionsSize,
 186       "%a%a",
 187       (CommandLineSize == 0) ?  "" : CommandLine,
 188       (InitrdSize == 0)      ?  "" : " initrd=initrd"
 189       );
 190     DEBUG ((DEBUG_INFO, "%a: command line: \"%s\"\n", __FUNCTION__,
 191       (CHAR16 *)KernelLoadedImage->LoadOptions));
 192   }
 193
 194   *ImageHandle = KernelImageHandle;
 195   return EFI_SUCCESS;
 196
 197 FreeCommandLine:
 198   if (CommandLineSize > 0) {
 199     FreePool (CommandLine);
 200   }
 201 UnloadImage:
 202   gBS->UnloadImage (KernelImageHandle);
 203
 204   return Status;
 205 }
 206
 207 /**
 208   Transfer control to a kernel image loaded with QemuLoadKernelImage ()
 209
 210   @param[in,out]  ImageHandle     Handle of image to be started. May assume a
 211                                   different value on return if the image was
 212                                   reloaded.
 213
 214   @retval EFI_INVALID_PARAMETER   ImageHandle is either an invalid image handle
 215                                   or the image has already been initialized with
 216                                   StartImage
 217   @retval EFI_SECURITY_VIOLATION  The current platform policy specifies that the
 218                                   image should not be started.
 219
 220   @return                         Error codes returned by the started image
 221 **/
 222 EFI_STATUS
 223 EFIAPI
 224 QemuStartKernelImage (
 225   IN  OUT EFI_HANDLE          *ImageHandle
 226   )
 227 {
 228   return gBS->StartImage (
 229                 *ImageHandle,
 230                 NULL,              // ExitDataSize
 231                 NULL               // ExitData
 232                 );
 233 }
 234
 235 /**
 236   Unloads an image loaded with QemuLoadKernelImage ().
 237
 238   @param  ImageHandle             Handle that identifies the image to be
 239                                   unloaded.
 240
 241   @retval EFI_SUCCESS             The image has been unloaded.
 242   @retval EFI_UNSUPPORTED         The image has been started, and does not
 243                                   support unload.
 244   @retval EFI_INVALID_PARAMETER   ImageHandle is not a valid image handle.
 245
 246   @return                         Exit code from the image's unload function.
 247 **/
 248 EFI_STATUS
 249 EFIAPI
 250 QemuUnloadKernelImage (
 251   IN  EFI_HANDLE          ImageHandle
 252   )
 253 {
 254   EFI_LOADED_IMAGE_PROTOCOL   *KernelLoadedImage;
 255   EFI_STATUS                  Status;
 256
 257   Status = gBS->OpenProtocol (
 258                   ImageHandle,
 259                   &gEfiLoadedImageProtocolGuid,
 260                   (VOID **)&KernelLoadedImage,
 261                   gImageHandle,                  // AgentHandle
 262                   NULL,                          // ControllerHandle
 263                   EFI_OPEN_PROTOCOL_GET_PROTOCOL
 264                   );
 265   if (EFI_ERROR (Status)) {
 266     return EFI_INVALID_PARAMETER;
 267   }
 268
 269   if (KernelLoadedImage->LoadOptions != NULL) {
 270     FreePool (KernelLoadedImage->LoadOptions);
 271     KernelLoadedImage->LoadOptions = NULL;
 272   }
 273   KernelLoadedImage->LoadOptionsSize = 0;
 274
 275   return gBS->UnloadImage (ImageHandle);
 276 }