OvmfPkg/GenericQemuLoadImageLib: Read cmdline from QemuKernelLoaderFs

Remove the QemuFwCfgLib interface used to read the QEMU cmdline
(-append argument) and the initrd size.  Instead, use the synthetic
filesystem QemuKernelLoaderFs which has three files: "kernel", "initrd",
and "cmdline".

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Tobin Feldman-Fitzthum <tobin@linux.ibm.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3457
Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
Message-Id: <20210628105110.379951-5-dovmurik@linux.ibm.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>

2 files changed, 139 insertions, 15 deletions

diff --git a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
index 8a29976ae1..66e029397b 100644
--- a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
+++ b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
@@ -11,13 +11,14 @@
 #include <Base.h>

 #include <Guid/QemuKernelLoaderFsMedia.h>

 #include <Library/DebugLib.h>

+#include <Library/FileHandleLib.h>

 #include <Library/MemoryAllocationLib.h>

 #include <Library/PrintLib.h>

-#include <Library/QemuFwCfgLib.h>

 #include <Library/QemuLoadImageLib.h>

 #include <Library/UefiBootServicesTableLib.h>

 #include <Protocol/DevicePath.h>

 #include <Protocol/LoadedImage.h>

+#include <Protocol/SimpleFileSystem.h>

 

 #pragma pack (1)

 typedef struct {

@@ -30,6 +31,11 @@ typedef struct {
   KERNEL_FILE_DEVPATH       FileNode;

   EFI_DEVICE_PATH_PROTOCOL  EndNode;

 } KERNEL_VENMEDIA_FILE_DEVPATH;

+

+typedef struct {

+  VENDOR_DEVICE_PATH       VenMediaNode;

+  EFI_DEVICE_PATH_PROTOCOL EndNode;

+} SINGLE_VENMEDIA_NODE_DEVPATH;

 #pragma pack ()

 

 STATIC CONST KERNEL_VENMEDIA_FILE_DEVPATH mKernelDevicePath = {

@@ -51,6 +57,82 @@ STATIC CONST KERNEL_VENMEDIA_FILE_DEVPATH mKernelDevicePath = {
   }

 };

 

+STATIC CONST SINGLE_VENMEDIA_NODE_DEVPATH mQemuKernelLoaderFsDevicePath = {

+  {

+    {

+      MEDIA_DEVICE_PATH, MEDIA_VENDOR_DP,

+      { sizeof (VENDOR_DEVICE_PATH) }

+    },

+    QEMU_KERNEL_LOADER_FS_MEDIA_GUID

+  }, {

+    END_DEVICE_PATH_TYPE, END_ENTIRE_DEVICE_PATH_SUBTYPE,

+    { sizeof (EFI_DEVICE_PATH_PROTOCOL) }

+  }

+};

+

+STATIC

+EFI_STATUS

+GetQemuKernelLoaderBlobSize (

+  IN  EFI_FILE_HANDLE     Root,

+  IN  CHAR16              *FileName,

+  OUT UINTN               *Size

+  )

+{

+  EFI_STATUS      Status;

+  EFI_FILE_HANDLE FileHandle;

+  UINT64          FileSize;

+

+  Status = Root->Open (Root, &FileHandle, FileName, EFI_FILE_MODE_READ, 0);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+  Status = FileHandleGetSize (FileHandle, &FileSize);

+  if (EFI_ERROR (Status)) {

+    goto CloseFile;

+  }

+  if (FileSize > MAX_UINTN) {

+    Status = EFI_UNSUPPORTED;

+    goto CloseFile;

+  }

+  *Size = (UINTN)FileSize;

+  Status = EFI_SUCCESS;

+CloseFile:

+  FileHandle->Close (FileHandle);

+  return Status;

+}

+

+STATIC

+EFI_STATUS

+ReadWholeQemuKernelLoaderBlob (

+  IN  EFI_FILE_HANDLE     Root,

+  IN  CHAR16              *FileName,

+  IN  UINTN               Size,

+  OUT VOID                *Buffer

+  )

+{

+  EFI_STATUS      Status;

+  EFI_FILE_HANDLE FileHandle;

+  UINTN           ReadSize;

+

+  Status = Root->Open (Root, &FileHandle, FileName, EFI_FILE_MODE_READ, 0);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+  ReadSize = Size;

+  Status = FileHandle->Read (FileHandle, &ReadSize, Buffer);

+  if (EFI_ERROR (Status)) {

+    goto CloseFile;

+  }

+  if (ReadSize != Size) {

+    Status = EFI_PROTOCOL_ERROR;

+    goto CloseFile;

+  }

+  Status = EFI_SUCCESS;

+CloseFile:

+  FileHandle->Close (FileHandle);

+  return Status;

+}

+

 /**

   Download the kernel, the initial ramdisk, and the kernel command line from

   QEMU's fw_cfg. The kernel will be instructed via its command line to load

@@ -76,12 +158,16 @@ QemuLoadKernelImage (
   OUT EFI_HANDLE                  *ImageHandle

   )

 {

-  EFI_STATUS                Status;

-  EFI_HANDLE                KernelImageHandle;

-  EFI_LOADED_IMAGE_PROTOCOL *KernelLoadedImage;

-  UINTN                     CommandLineSize;

-  CHAR8                     *CommandLine;

-  UINTN                     InitrdSize;

+  EFI_STATUS                      Status;

+  EFI_HANDLE                      KernelImageHandle;

+  EFI_LOADED_IMAGE_PROTOCOL       *KernelLoadedImage;

+  EFI_DEVICE_PATH_PROTOCOL        *DevicePathNode;

+  EFI_HANDLE                      FsVolumeHandle;

+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *FsProtocol;

+  EFI_FILE_HANDLE                 Root;

+  UINTN                           CommandLineSize;

+  CHAR8                           *CommandLine;

+  UINTN                           InitrdSize;

 

   //

   // Load the image. This should call back into the QEMU EFI loader file system.

@@ -124,8 +210,38 @@ QemuLoadKernelImage (
                   );

   ASSERT_EFI_ERROR (Status);

 

-  QemuFwCfgSelectItem (QemuFwCfgItemCommandLineSize);

-  CommandLineSize = (UINTN)QemuFwCfgRead32 ();

+  //

+  // Open the Qemu Kernel Loader abstract filesystem (volume) which will be

+  // used to query the "initrd" and to read the "cmdline" synthetic files.

+  //

+  DevicePathNode = (EFI_DEVICE_PATH_PROTOCOL *)&mQemuKernelLoaderFsDevicePath;

+  Status = gBS->LocateDevicePath (

+                  &gEfiSimpleFileSystemProtocolGuid,

+                  &DevicePathNode,

+                  &FsVolumeHandle

+                  );

+  if (EFI_ERROR (Status)) {

+    goto UnloadImage;

+  }

+

+  Status = gBS->HandleProtocol (

+                  FsVolumeHandle,

+                  &gEfiSimpleFileSystemProtocolGuid,

+                  (VOID **)&FsProtocol

+                  );

+  if (EFI_ERROR (Status)) {

+    goto UnloadImage;

+  }

+

+  Status = FsProtocol->OpenVolume (FsVolumeHandle, &Root);

+  if (EFI_ERROR (Status)) {

+    goto UnloadImage;

+  }

+

+  Status = GetQemuKernelLoaderBlobSize (Root, L"cmdline", &CommandLineSize);

+  if (EFI_ERROR (Status)) {

+    goto CloseRoot;

+  }

 

   if (CommandLineSize == 0) {

     KernelLoadedImage->LoadOptionsSize = 0;

@@ -133,11 +249,14 @@ QemuLoadKernelImage (
     CommandLine = AllocatePool (CommandLineSize);

     if (CommandLine == NULL) {

       Status = EFI_OUT_OF_RESOURCES;

-      goto UnloadImage;

+      goto CloseRoot;

     }

 

-    QemuFwCfgSelectItem (QemuFwCfgItemCommandLineData);

-    QemuFwCfgReadBytes (CommandLineSize, CommandLine);

+    Status = ReadWholeQemuKernelLoaderBlob (Root, L"cmdline", CommandLineSize,

+               CommandLine);

+    if (EFI_ERROR (Status)) {

+      goto FreeCommandLine;

+    }

 

     //

     // Verify NUL-termination of the command line.

@@ -155,8 +274,10 @@ QemuLoadKernelImage (
     KernelLoadedImage->LoadOptionsSize = (UINT32)((CommandLineSize - 1) * 2);

   }

 

-  QemuFwCfgSelectItem (QemuFwCfgItemInitrdSize);

-  InitrdSize = (UINTN)QemuFwCfgRead32 ();

+  Status = GetQemuKernelLoaderBlobSize (Root, L"initrd", &InitrdSize);

+  if (EFI_ERROR (Status)) {

+    goto FreeCommandLine;

+  }

 

   if (InitrdSize > 0) {

     //

@@ -199,6 +320,8 @@ FreeCommandLine:
   if (CommandLineSize > 0) {

     FreePool (CommandLine);

   }

+CloseRoot:

+  Root->Close (Root);

 UnloadImage:

   if (EFI_ERROR (Status)) {

     gBS->UnloadImage (KernelImageHandle);

diff --git a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
index b262cb926a..9c9e35b1c5 100644
--- a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
+++ b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
@@ -25,14 +25,15 @@
 

 [LibraryClasses]

   DebugLib

+  FileHandleLib

   MemoryAllocationLib

   PrintLib

-  QemuFwCfgLib

   UefiBootServicesTableLib

 

 [Protocols]

   gEfiDevicePathProtocolGuid

   gEfiLoadedImageProtocolGuid

+  gEfiSimpleFileSystemProtocolGuid

 

 [Guids]

   gQemuKernelLoaderFsMediaGuid