OvmfPkg/VirtioFsDxe: DriverBinding: open VirtioDevice, install SimpleFs

Complete the Supported, Start, and Stop member functions of
EFI_DRIVER_BINDING_PROTOCOL sufficiently for exercising the UEFI driver
model:

- bind virtio-fs devices,

- produce placeholder EFI_SIMPLE_FILE_SYSTEM_PROTOCOL instances on them.

On the "TO_START" (= Virtio) side, the VirtioFsBindingSupported() function
verifies the Virtio subsystem ID for the virtio-fs device (decimal 26 --
see
<https://github.com/oasis-tcs/virtio-spec/blob/87fa6b5d8155/virtio-fs.tex>).
Beyond that, no actual Virtio setup is performed for now. Those bits are
going to be implemented later in this series.

On the "BY_START" (= UEFI filesystem) side, the VirtioFsOpenVolume()
function -- which is the sole EFI_SIMPLE_FILE_SYSTEM_PROTOCOL member
function -- is a stub; it always returns EFI_NO_MEDIA, for now.

The "CONNECT", "DISCONNECT", and "MAP -R" UEFI Shell commands can be used
to test this patch.

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20201216211125.19496-4-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

5 files changed, 181 insertions, 3 deletions

diff --git a/OvmfPkg/Include/IndustryStandard/Virtio10.h b/OvmfPkg/Include/IndustryStandard/Virtio10.h
index 3c1592d1fd..2c60be2b7c 100644
--- a/OvmfPkg/Include/IndustryStandard/Virtio10.h
+++ b/OvmfPkg/Include/IndustryStandard/Virtio10.h
@@ -17,6 +17,11 @@
 // Subsystem Device IDs (to be) introduced in VirtIo 1.0

 //

 #define VIRTIO_SUBSYSTEM_GPU_DEVICE         16

+//

+// Subsystem Device IDs from the VirtIo spec at git commit 87fa6b5d8155;

+// <https://github.com/oasis-tcs/virtio-spec/tree/87fa6b5d8155>.

+//

+#define VIRTIO_SUBSYSTEM_FILESYSTEM         26

 

 //

 // Structures for parsing the VirtIo 1.0 specific PCI capabilities from the

diff --git a/OvmfPkg/VirtioFsDxe/DriverBinding.c b/OvmfPkg/VirtioFsDxe/DriverBinding.c
index ac0a6330f0..65e45b5c4b 100644
--- a/OvmfPkg/VirtioFsDxe/DriverBinding.c
+++ b/OvmfPkg/VirtioFsDxe/DriverBinding.c
@@ -6,11 +6,15 @@
   SPDX-License-Identifier: BSD-2-Clause-Patent

 **/

 

+#include <IndustryStandard/Virtio.h>          // VIRTIO_SUBSYSTEM_FILESYSTEM

 #include <Library/BaseLib.h>                  // AsciiStrCmp()

+#include <Library/MemoryAllocationLib.h>      // AllocatePool()

 #include <Library/UefiBootServicesTableLib.h> // gBS

 #include <Protocol/ComponentName2.h>          // EFI_COMPONENT_NAME2_PROTOCOL

 #include <Protocol/DriverBinding.h>           // EFI_DRIVER_BINDING_PROTOCOL

 

+#include "VirtioFsDxe.h"

+

 //

 // UEFI Driver Model protocol instances.

 //

@@ -28,7 +32,27 @@ VirtioFsBindingSupported (
   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath OPTIONAL

   )

 {

-  return EFI_UNSUPPORTED;

+  EFI_STATUS             Status;

+  VIRTIO_DEVICE_PROTOCOL *Virtio;

+  EFI_STATUS             CloseStatus;

+

+  Status = gBS->OpenProtocol (ControllerHandle, &gVirtioDeviceProtocolGuid,

+                  (VOID **)&Virtio, This->DriverBindingHandle,

+                  ControllerHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+

+  if (Virtio->SubSystemDeviceId != VIRTIO_SUBSYSTEM_FILESYSTEM) {

+    Status = EFI_UNSUPPORTED;

+  }

+

+  CloseStatus = gBS->CloseProtocol (ControllerHandle,

+                       &gVirtioDeviceProtocolGuid, This->DriverBindingHandle,

+                       ControllerHandle);

+  ASSERT_EFI_ERROR (CloseStatus);

+

+  return Status;

 }

 

 EFI_STATUS

@@ -39,7 +63,45 @@ VirtioFsBindingStart (
   IN EFI_DEVICE_PATH_PROTOCOL    *RemainingDevicePath OPTIONAL

   )

 {

-  return EFI_DEVICE_ERROR;

+  VIRTIO_FS  *VirtioFs;

+  EFI_STATUS Status;

+  EFI_STATUS CloseStatus;

+

+  VirtioFs = AllocatePool (sizeof *VirtioFs);

+  if (VirtioFs == NULL) {

+    return EFI_OUT_OF_RESOURCES;

+  }

+  VirtioFs->Signature = VIRTIO_FS_SIG;

+

+  Status = gBS->OpenProtocol (ControllerHandle, &gVirtioDeviceProtocolGuid,

+                  (VOID **)&VirtioFs->Virtio, This->DriverBindingHandle,

+                  ControllerHandle, EFI_OPEN_PROTOCOL_BY_DRIVER);

+  if (EFI_ERROR (Status)) {

+    goto FreeVirtioFs;

+  }

+

+  VirtioFs->SimpleFs.Revision   = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION;

+  VirtioFs->SimpleFs.OpenVolume = VirtioFsOpenVolume;

+

+  Status = gBS->InstallProtocolInterface (&ControllerHandle,

+                  &gEfiSimpleFileSystemProtocolGuid, EFI_NATIVE_INTERFACE,

+                  &VirtioFs->SimpleFs);

+  if (EFI_ERROR (Status)) {

+    goto CloseVirtio;

+  }

+

+  return EFI_SUCCESS;

+

+CloseVirtio:

+  CloseStatus = gBS->CloseProtocol (ControllerHandle,

+                       &gVirtioDeviceProtocolGuid, This->DriverBindingHandle,

+                       ControllerHandle);

+  ASSERT_EFI_ERROR (CloseStatus);

+

+FreeVirtioFs:

+  FreePool (VirtioFs);

+

+  return Status;

 }

 

 EFI_STATUS

@@ -51,7 +113,33 @@ VirtioFsBindingStop (
   IN EFI_HANDLE                  *ChildHandleBuffer OPTIONAL

   )

 {

-  return EFI_DEVICE_ERROR;

+  EFI_STATUS                      Status;

+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *SimpleFs;

+  VIRTIO_FS                       *VirtioFs;

+

+  Status = gBS->OpenProtocol (ControllerHandle,

+                  &gEfiSimpleFileSystemProtocolGuid, (VOID **)&SimpleFs,

+                  This->DriverBindingHandle, ControllerHandle,

+                  EFI_OPEN_PROTOCOL_GET_PROTOCOL);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+

+  VirtioFs = VIRTIO_FS_FROM_SIMPLE_FS (SimpleFs);

+

+  Status = gBS->UninstallProtocolInterface (ControllerHandle,

+                  &gEfiSimpleFileSystemProtocolGuid, SimpleFs);

+  if (EFI_ERROR (Status)) {

+    return Status;

+  }

+

+  Status = gBS->CloseProtocol (ControllerHandle, &gVirtioDeviceProtocolGuid,

+                  This->DriverBindingHandle, ControllerHandle);

+  ASSERT_EFI_ERROR (Status);

+

+  FreePool (VirtioFs);

+

+  return EFI_SUCCESS;

 }

 

 EFI_STATUS

diff --git a/OvmfPkg/VirtioFsDxe/SimpleFsOpenVolume.c b/OvmfPkg/VirtioFsDxe/SimpleFsOpenVolume.c
new file mode 100644
index 0000000000..a5a66a27d8
--- /dev/null
+++ b/OvmfPkg/VirtioFsDxe/SimpleFsOpenVolume.c
@@ -0,0 +1,26 @@
+/** @file

+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL.OpenVolume() member function for the Virtio

+  Filesystem driver.

+

+  Copyright (C) 2020, Red Hat, Inc.

+

+  SPDX-License-Identifier: BSD-2-Clause-Patent

+**/

+

+#include "VirtioFsDxe.h"

+

+/**

+  Open the root directory on the Virtio Filesystem.

+

+  Refer to EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_OPEN_VOLUME for the interface

+  contract.

+**/

+EFI_STATUS

+EFIAPI

+VirtioFsOpenVolume (

+  IN  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *This,

+  OUT EFI_FILE_PROTOCOL               **Root

+  )

+{

+  return EFI_NO_MEDIA;

+}

diff --git a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
new file mode 100644
index 0000000000..287defd21f
--- /dev/null
+++ b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
@@ -0,0 +1,52 @@
+/** @file

+  Internal macro definitions, type definitions, and function declarations for

+  the Virtio Filesystem device driver.

+

+  Copyright (C) 2020, Red Hat, Inc.

+

+  SPDX-License-Identifier: BSD-2-Clause-Patent

+**/

+

+#ifndef VIRTIO_FS_DXE_H_

+#define VIRTIO_FS_DXE_H_

+

+#include <Base.h>                      // SIGNATURE_64()

+#include <Library/DebugLib.h>          // CR()

+#include <Protocol/SimpleFileSystem.h> // EFI_SIMPLE_FILE_SYSTEM_PROTOCOL

+#include <Protocol/VirtioDevice.h>     // VIRTIO_DEVICE_PROTOCOL

+

+#define VIRTIO_FS_SIG SIGNATURE_64 ('V', 'I', 'R', 'T', 'I', 'O', 'F', 'S')

+

+//

+// Main context structure, expressing an EFI_SIMPLE_FILE_SYSTEM_PROTOCOL

+// interface on top of the Virtio Filesystem device.

+//

+typedef struct {

+  //

+  // Parts of this structure are initialized / torn down in various functions

+  // at various call depths. The table to the right should make it easier to

+  // track them.

+  //

+  //                              field         init function       init depth

+  //                              -----------   ------------------  ----------

+  UINT64                          Signature; // DriverBindingStart  0

+  VIRTIO_DEVICE_PROTOCOL          *Virtio;   // DriverBindingStart  0

+  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL SimpleFs;  // DriverBindingStart  0

+} VIRTIO_FS;

+

+#define VIRTIO_FS_FROM_SIMPLE_FS(SimpleFsReference) \

+  CR (SimpleFsReference, VIRTIO_FS, SimpleFs, VIRTIO_FS_SIG);

+

+//

+// EFI_SIMPLE_FILE_SYSTEM_PROTOCOL member functions for the Virtio Filesystem

+// driver.

+//

+

+EFI_STATUS

+EFIAPI

+VirtioFsOpenVolume (

+  IN  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *This,

+  OUT EFI_FILE_PROTOCOL               **Root

+  );

+

+#endif // VIRTIO_FS_DXE_H_

diff --git a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
index 69cb44bc7c..ff9b1c6178 100644
--- a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
+++ b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
@@ -78,15 +78,22 @@
 

 [Packages]

   MdePkg/MdePkg.dec

+  OvmfPkg/OvmfPkg.dec

 

 [Sources]

   DriverBinding.c

+  SimpleFsOpenVolume.c

+  VirtioFsDxe.h

 

 [LibraryClasses]

   BaseLib

+  DebugLib

+  MemoryAllocationLib

   UefiBootServicesTableLib

   UefiDriverEntryPoint

 

 [Protocols]

   gEfiComponentName2ProtocolGuid        ## PRODUCES

   gEfiDriverBindingProtocolGuid         ## PRODUCES

+  gEfiSimpleFileSystemProtocolGuid      ## BY_START

+  gVirtioDeviceProtocolGuid             ## TO_START