[PATCH v2 0/3] OvmfPkg: Use QemuKernelLoaderFs to read cmdline/initrd

[PATCH v2 0/3] OvmfPkg: Use QemuKernelLoaderFs to read cmdline/initrd

[Dov Murik]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3457

In order to support measured SEV boot with kernel/initrd/cmdline, we'd
like to have one place that reads those blobs; in the future we'll add
the measurement and verification in that place.

We already have a synthetic filesystem (QemuKernelLoaderFs) which holds
three files: "kernel", "initrd", and "cmdline".  The kernel is indeed
read from this filesystem in LoadImage; but the cmdline (and the length
of initrd) are read from QemuFwCfgLib items.

This patch series modifies GenericQemuLoadImageLib to read cmdline (and
the initrd size) from the QemuKernelLoaderFs synthetic filesystem, thus
removing the dependency on QemuFwCfgLib.

Note that X86QemuLoadImageLib is not modified, because it contains a
QemuLoadLegacyImage() which reads other items of the QemuFwCfg which are
not available in QemuKernelLoaderFs.  Since we don't want to support the
legacy boot path in the future measured SEV boot, we leave
X86QemuLoadImageLib as-is (except for a comment addition in patch 3) and
will force use for GenericQemuLoadImageLib in the measured SEV boot
implementation.

Relevant discussion threads start in:
https://edk2.groups.io/g/devel/message/76069

To test this on x86_64, I forced the use of GenericQemuLoadImageLib
using the following local patch:


diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 0a237a905866..46442b543bcf 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -404,7 +404,7 @@ [LibraryClasses.common.DXE_DRIVER]
   PciLib|OvmfPkg/Library/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf
   MpInitLib|UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
   QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/DxeQemuFwCfgS3LibFwCfg.inf
-  QemuLoadImageLib|OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
+  QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf # XXX don't commit this or someone will be mad
 !if $(TPM_ENABLE) == TRUE
   Tpm12DeviceLib|SecurityPkg/Library/Tpm12DeviceLibTcg/Tpm12DeviceLibTcg.inf
   Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf


I tested boot with QEMU and OVMF with the following QEMU arguments:

  -kernel a
  -kernel a -initrd b
  -kernel a -cmdline c
  -kernel a -initrd b -cmdline c

(and also without -kernel)


Code is at
https://github.com/confidential-containers-demo/edk2/tree/use-synthetic-fs-for-cmdline-v2

v2 changes:

 - Add comment to header of X86QemuLoadImageLib.inf
 - Clearer function names in GenericQemuLoadImageLib.c
 - Fix coding style issues

v1: https://edk2.groups.io/g/devel/message/76265


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>

Dov Murik (3):
  Revert "OvmfPkg/QemuKernelLoaderFsDxe: don't expose kernel command
    line"
  OvmfPkg/GenericQemuLoadImageLib: Read cmdline from QemuKernelLoaderFs
  OvmfPkg/X86QemuLoadImageLib: State fw_cfg dependency in file header

 OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf |   2 +-
 OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf         |   3 +
 OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c   | 145 ++++++++++++++++++--
 OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c           |   3 +
 OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c               |  11 +-
 5 files changed, 147 insertions(+), 17 deletions(-)

-- 
2.25.1

[PATCH v2 1/3] Revert "OvmfPkg/QemuKernelLoaderFsDxe: don't expose kernel command line"

[Dov Murik]

This reverts commit efc52d67e1573ce174d301b52fa1577d552c8441.

Manually fixed conflicts in:
  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c

Note that besides re-exposing the kernel command line as a file in the
synthetic filesystem, we also revert back to AllocatePool instead of
AllocatePages.

Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
---
 OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
index b09ff6a3590d..c7ddd86f5c75 100644
--- a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
+++ b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
@@ -33,6 +33,7 @@
 typedef enum {
   KernelBlobTypeKernel,
   KernelBlobTypeInitrd,
+  KernelBlobTypeCommandLine,
   KernelBlobTypeMax
 } KERNEL_BLOB_TYPE;
 
@@ -59,6 +60,11 @@ STATIC KERNEL_BLOB mKernelBlob[KernelBlobTypeMax] = {
     {
       { QemuFwCfgItemInitrdSize,      QemuFwCfgItemInitrdData,      },
     }
+  }, {
+    L"cmdline",
+    {
+      { QemuFwCfgItemCommandLineSize, QemuFwCfgItemCommandLineData, },
+    }
   }
 };
 
@@ -948,7 +954,7 @@ FetchBlob (
   //
   // Read blob.
   //
-  Blob->Data = AllocatePages (EFI_SIZE_TO_PAGES ((UINTN)Blob->Size));
+  Blob->Data = AllocatePool (Blob->Size);
   if (Blob->Data == NULL) {
     DEBUG ((DEBUG_ERROR, "%a: failed to allocate %Ld bytes for \"%s\"\n",
       __FUNCTION__, (INT64)Blob->Size, Blob->Name));
@@ -1083,8 +1089,7 @@ FreeBlobs:
   while (BlobType > 0) {
     CurrentBlob = &mKernelBlob[--BlobType];
     if (CurrentBlob->Data != NULL) {
-      FreePages (CurrentBlob->Data,
-        EFI_SIZE_TO_PAGES ((UINTN)CurrentBlob->Size));
+      FreePool (CurrentBlob->Data);
       CurrentBlob->Size = 0;
       CurrentBlob->Data = NULL;
     }
-- 
2.25.1

[PATCH v2 2/3] OvmfPkg/GenericQemuLoadImageLib: Read cmdline from QemuKernelLoaderFs

[Dov Murik]

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".

Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
---
 OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf |   2 +-
 OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c   | 145 ++++++++++++++++++--
 2 files changed, 133 insertions(+), 14 deletions(-)

diff --git a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
index b262cb926a4d..f462fd6922cf 100644
--- a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
+++ b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf
@@ -27,12 +27,12 @@ [LibraryClasses]
   DebugLib
   MemoryAllocationLib
   PrintLib
-  QemuFwCfgLib
   UefiBootServicesTableLib
 
 [Protocols]
   gEfiDevicePathProtocolGuid
   gEfiLoadedImageProtocolGuid
+  gEfiSimpleFileSystemProtocolGuid
 
 [Guids]
   gQemuKernelLoaderFsMediaGuid
diff --git a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
index 114db7e8441f..f520456e3b24 100644
--- a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
+++ b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
@@ -11,9 +11,9 @@
 #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>
@@ -30,6 +30,11 @@ 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 +56,78 @@ STATIC CONST KERNEL_VENMEDIA_FILE_DEVPATH mKernelDevicePath = {
   }
 };
 
+STATIC CONST SINGLE_VENMEDIA_NODE_DEVPATH mQemuKernelLoaderFileSystemDevicePath = {
+  {
+    {
+      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;
+  }
+  *Size = 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 +153,16 @@ 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 +205,38 @@ QemuLoadKernelImage (
                   );
   ASSERT_EFI_ERROR (Status);
 
-  QemuFwCfgSelectItem (QemuFwCfgItemCommandLineSize);
-  CommandLineSize = (UINTN)QemuFwCfgRead32 ();
+  //
+  // Open the Qemu Kernel Loader abstract filesystem (volume) which will be
+  // used to read the "initrd" and "cmdline" synthetic files.
+  //
+  DevicePathNode = (EFI_DEVICE_PATH_PROTOCOL *)&mQemuKernelLoaderFileSystemDevicePath;
+  Status = gBS->LocateDevicePath (
+                  &gEfiSimpleFileSystemProtocolGuid,
+                  &DevicePathNode,
+                  &FsVolumeHandle
+                  );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = gBS->HandleProtocol (
+                  FsVolumeHandle,
+                  &gEfiSimpleFileSystemProtocolGuid,
+                  (VOID **)&FsProtocol
+                  );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = FsProtocol->OpenVolume (FsVolumeHandle, &Root);
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  Status = GetQemuKernelLoaderBlobSize (Root, L"cmdline", &CommandLineSize);
+  if (EFI_ERROR (Status)) {
+    goto CloseRoot;
+  }
 
   if (CommandLineSize == 0) {
     KernelLoadedImage->LoadOptionsSize = 0;
@@ -136,8 +247,11 @@ QemuLoadKernelImage (
       goto UnloadImage;
     }
 
-    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 +269,10 @@ 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) {
     //
@@ -193,6 +309,7 @@ QemuLoadKernelImage (
   }
 
   *ImageHandle = KernelImageHandle;
+  Root->Close (Root);
   return EFI_SUCCESS;
 
 FreeCommandLine:
@@ -201,6 +318,8 @@ FreeCommandLine:
   }
 UnloadImage:
   gBS->UnloadImage (KernelImageHandle);
+CloseRoot:
+  Root->Close (Root);
 
   return Status;
 }
-- 
2.25.1

[PATCH v2 3/3] OvmfPkg/X86QemuLoadImageLib: State fw_cfg dependency in file header

[Dov Murik]

Make it clear that X86QemuLoadImageLib relies on fw_cfg; prepare the
ground to add a warning about the incompatibility with boot verification
process.

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>
Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
---
 OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf | 3 +++
 OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf b/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
index e1615badd2ba..c7ec041cb706 100644
--- a/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
+++ b/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
@@ -2,6 +2,9 @@
 #  X86 specific implementation of QemuLoadImageLib library class interface
 #  with support for loading mixed mode images and non-EFI stub images
 #
+#  Note that this implementation reads the cmdline (and possibly kernel, setup
+#  data, and initrd in the legacy boot mode) from fw_cfg directly.
+#
 #  Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
 #
 #  SPDX-License-Identifier: BSD-2-Clause-Patent
diff --git a/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c b/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
index 1177582ab051..dc9018f4333b 100644
--- a/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
+++ b/OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c
@@ -2,6 +2,9 @@
   X86 specific implementation of QemuLoadImageLib library class interface
   with support for loading mixed mode images and non-EFI stub images
 
+  Note that this implementation reads the cmdline (and possibly kernel, setup
+  data, and initrd in the legacy boot mode) from fw_cfg directly.
+
   Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
   Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
 
-- 
2.25.1

Re: [edk2-devel] [PATCH v2 0/3] OvmfPkg: Use QemuKernelLoaderFs to read cmdline/initrd

[Ard Biesheuvel]

On Thu, 17 Jun 2021 at 11:12, Dov Murik <dovmurik@linux.ibm.com> wrote:
>
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3457
>
> In order to support measured SEV boot with kernel/initrd/cmdline, we'd
> like to have one place that reads those blobs; in the future we'll add
> the measurement and verification in that place.
>
> We already have a synthetic filesystem (QemuKernelLoaderFs) which holds
> three files: "kernel", "initrd", and "cmdline".  The kernel is indeed
> read from this filesystem in LoadImage; but the cmdline (and the length
> of initrd) are read from QemuFwCfgLib items.
>
> This patch series modifies GenericQemuLoadImageLib to read cmdline (and
> the initrd size) from the QemuKernelLoaderFs synthetic filesystem, thus
> removing the dependency on QemuFwCfgLib.
>
> Note that X86QemuLoadImageLib is not modified, because it contains a
> QemuLoadLegacyImage() which reads other items of the QemuFwCfg which are
> not available in QemuKernelLoaderFs.  Since we don't want to support the
> legacy boot path in the future measured SEV boot, we leave
> X86QemuLoadImageLib as-is (except for a comment addition in patch 3) and
> will force use for GenericQemuLoadImageLib in the measured SEV boot
> implementation.
>
> Relevant discussion threads start in:
> https://edk2.groups.io/g/devel/message/76069
>
> To test this on x86_64, I forced the use of GenericQemuLoadImageLib
> using the following local patch:
>
>
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index 0a237a905866..46442b543bcf 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -404,7 +404,7 @@ [LibraryClasses.common.DXE_DRIVER]
>    PciLib|OvmfPkg/Library/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf
>    MpInitLib|UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
>    QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/DxeQemuFwCfgS3LibFwCfg.inf
> -  QemuLoadImageLib|OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
> +  QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf # XXX don't commit this or someone will be mad
>  !if $(TPM_ENABLE) == TRUE
>    Tpm12DeviceLib|SecurityPkg/Library/Tpm12DeviceLibTcg/Tpm12DeviceLibTcg.inf
>    Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf
>
>
> I tested boot with QEMU and OVMF with the following QEMU arguments:
>
>   -kernel a
>   -kernel a -initrd b
>   -kernel a -cmdline c
>   -kernel a -initrd b -cmdline c
>
> (and also without -kernel)
>
>
> Code is at
> https://github.com/confidential-containers-demo/edk2/tree/use-synthetic-fs-for-cmdline-v2
>
> v2 changes:
>
>  - Add comment to header of X86QemuLoadImageLib.inf
>  - Clearer function names in GenericQemuLoadImageLib.c
>  - Fix coding style issues
>
> v1: https://edk2.groups.io/g/devel/message/76265
>
>
> 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>
>
> Dov Murik (3):
>   Revert "OvmfPkg/QemuKernelLoaderFsDxe: don't expose kernel command
>     line"
>   OvmfPkg/GenericQemuLoadImageLib: Read cmdline from QemuKernelLoaderFs
>   OvmfPkg/X86QemuLoadImageLib: State fw_cfg dependency in file header
>


Please cc me on the entire series.


>  OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf |   2 +-
>  OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf         |   3 +
>  OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c   | 145 ++++++++++++++++++--
>  OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c           |   3 +
>  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c               |  11 +-
>  5 files changed, 147 insertions(+), 17 deletions(-)
>
> --
> 2.25.1
>
>
>
> 
>
>

[PATCH v2 1/3] Revert "OvmfPkg/QemuKernelLoaderFsDxe: don't expose kernel command line"

[Dov Murik]

This reverts commit efc52d67e1573ce174d301b52fa1577d552c8441.

Manually fixed conflicts in:
  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c

Note that besides re-exposing the kernel command line as a file in the
synthetic filesystem, we also revert back to AllocatePool instead of
AllocatePages.

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>
Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
---
 OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
index b09ff6a3590d..c7ddd86f5c75 100644
--- a/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
+++ b/OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c
@@ -33,6 +33,7 @@
 typedef enum {
   KernelBlobTypeKernel,
   KernelBlobTypeInitrd,
+  KernelBlobTypeCommandLine,
   KernelBlobTypeMax
 } KERNEL_BLOB_TYPE;
 
@@ -59,6 +60,11 @@ STATIC KERNEL_BLOB mKernelBlob[KernelBlobTypeMax] = {
     {
       { QemuFwCfgItemInitrdSize,      QemuFwCfgItemInitrdData,      },
     }
+  }, {
+    L"cmdline",
+    {
+      { QemuFwCfgItemCommandLineSize, QemuFwCfgItemCommandLineData, },
+    }
   }
 };
 
@@ -948,7 +954,7 @@ FetchBlob (
   //
   // Read blob.
   //
-  Blob->Data = AllocatePages (EFI_SIZE_TO_PAGES ((UINTN)Blob->Size));
+  Blob->Data = AllocatePool (Blob->Size);
   if (Blob->Data == NULL) {
     DEBUG ((DEBUG_ERROR, "%a: failed to allocate %Ld bytes for \"%s\"\n",
       __FUNCTION__, (INT64)Blob->Size, Blob->Name));
@@ -1083,8 +1089,7 @@ FreeBlobs:
   while (BlobType > 0) {
     CurrentBlob = &mKernelBlob[--BlobType];
     if (CurrentBlob->Data != NULL) {
-      FreePages (CurrentBlob->Data,
-        EFI_SIZE_TO_PAGES ((UINTN)CurrentBlob->Size));
+      FreePool (CurrentBlob->Data);
       CurrentBlob->Size = 0;
       CurrentBlob->Data = NULL;
     }
-- 
2.25.1

Re: [edk2-devel] [PATCH v2 0/3] OvmfPkg: Use QemuKernelLoaderFs to read cmdline/initrd

[Dov Murik]

On 17/06/2021 15:01, Ard Biesheuvel wrote:
> On Thu, 17 Jun 2021 at 11:12, Dov Murik <dovmurik@linux.ibm.com> wrote:
>>
>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3457
>>
>> In order to support measured SEV boot with kernel/initrd/cmdline, we'd
>> like to have one place that reads those blobs; in the future we'll add
>> the measurement and verification in that place.
>>
>> We already have a synthetic filesystem (QemuKernelLoaderFs) which holds
>> three files: "kernel", "initrd", and "cmdline".  The kernel is indeed
>> read from this filesystem in LoadImage; but the cmdline (and the length
>> of initrd) are read from QemuFwCfgLib items.
>>
>> This patch series modifies GenericQemuLoadImageLib to read cmdline (and
>> the initrd size) from the QemuKernelLoaderFs synthetic filesystem, thus
>> removing the dependency on QemuFwCfgLib.
>>
>> Note that X86QemuLoadImageLib is not modified, because it contains a
>> QemuLoadLegacyImage() which reads other items of the QemuFwCfg which are
>> not available in QemuKernelLoaderFs.  Since we don't want to support the
>> legacy boot path in the future measured SEV boot, we leave
>> X86QemuLoadImageLib as-is (except for a comment addition in patch 3) and
>> will force use for GenericQemuLoadImageLib in the measured SEV boot
>> implementation.
>>
>> Relevant discussion threads start in:
>> https://edk2.groups.io/g/devel/message/76069
>>
>> To test this on x86_64, I forced the use of GenericQemuLoadImageLib
>> using the following local patch:
>>
>>
>> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
>> index 0a237a905866..46442b543bcf 100644
>> --- a/OvmfPkg/OvmfPkgX64.dsc
>> +++ b/OvmfPkg/OvmfPkgX64.dsc
>> @@ -404,7 +404,7 @@ [LibraryClasses.common.DXE_DRIVER]
>>    PciLib|OvmfPkg/Library/DxePciLibI440FxQ35/DxePciLibI440FxQ35.inf
>>    MpInitLib|UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
>>    QemuFwCfgS3Lib|OvmfPkg/Library/QemuFwCfgS3Lib/DxeQemuFwCfgS3LibFwCfg.inf
>> -  QemuLoadImageLib|OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf
>> +  QemuLoadImageLib|OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf # XXX don't commit this or someone will be mad
>>  !if $(TPM_ENABLE) == TRUE
>>    Tpm12DeviceLib|SecurityPkg/Library/Tpm12DeviceLibTcg/Tpm12DeviceLibTcg.inf
>>    Tpm2DeviceLib|SecurityPkg/Library/Tpm2DeviceLibTcg2/Tpm2DeviceLibTcg2.inf
>>
>>
>> I tested boot with QEMU and OVMF with the following QEMU arguments:
>>
>>   -kernel a
>>   -kernel a -initrd b
>>   -kernel a -cmdline c
>>   -kernel a -initrd b -cmdline c
>>
>> (and also without -kernel)
>>
>>
>> Code is at
>> https://github.com/confidential-containers-demo/edk2/tree/use-synthetic-fs-for-cmdline-v2
>>
>> v2 changes:
>>
>>  - Add comment to header of X86QemuLoadImageLib.inf
>>  - Clearer function names in GenericQemuLoadImageLib.c
>>  - Fix coding style issues
>>
>> v1: https://edk2.groups.io/g/devel/message/76265
>>
>>
>> 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>
>>
>> Dov Murik (3):
>>   Revert "OvmfPkg/QemuKernelLoaderFsDxe: don't expose kernel command
>>     line"
>>   OvmfPkg/GenericQemuLoadImageLib: Read cmdline from QemuKernelLoaderFs
>>   OvmfPkg/X86QemuLoadImageLib: State fw_cfg dependency in file header
>>
> 
> 
> Please cc me on the entire series.
> 

Sorry, my bad. Resent.

-Dov


> 
>>  OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.inf |   2 +-
>>  OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.inf         |   3 +
>>  OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c   | 145 ++++++++++++++++++--
>>  OvmfPkg/Library/X86QemuLoadImageLib/X86QemuLoadImageLib.c           |   3 +
>>  OvmfPkg/QemuKernelLoaderFsDxe/QemuKernelLoaderFsDxe.c               |  11 +-
>>  5 files changed, 147 insertions(+), 17 deletions(-)
>>
>> --
>> 2.25.1
>>
>>
>>
>> 
>>
>>