OvmfPkg/VirtioFsDxe: implement virtio device (un)initialization

Add the VirtioFsInit(), VirtioFsUninit(), and VirtioFsExitBoot()
functions.

In VirtioFsInit():

- Verify the host-side config of the virtio-fs device.

- Save the filesystem label ("tag") for later, from the configuration area
  of the virtio-fs device.

- Save the virtio queue size for later as well.

- Set up the virtio ring for sending requests.

In VirtioFsUninit():

- Reset the device.

- Tear down the virtio ring.

In VirtioFsExitBoot():

- Reset the device.

With this patch, the UEFI connect / disconnect controller operations
involve virtio setup / teardown; they are visible in the virtio-fs
daemon's log file. The virtiofsd log also confirms the device reset in
VirtioFsExitBoot(), when an OS is booted while the virtio-fs device is
bound.

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: <20201216211125.19496-5-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

5 files changed, 412 insertions, 2 deletions

diff --git a/OvmfPkg/Include/IndustryStandard/VirtioFs.h b/OvmfPkg/Include/IndustryStandard/VirtioFs.h
new file mode 100644
index 0000000000..ea7d80d15d
--- /dev/null
+++ b/OvmfPkg/Include/IndustryStandard/VirtioFs.h
@@ -0,0 +1,52 @@
+/** @file

+  Type and macro definitions specific to the Virtio Filesystem device.

+

+  At the time of this writing, the latest released Virtio specification (v1.1)

+  does not include the virtio-fs device. The development version of the

+  specification defines it however; see the latest version at

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

+

+  This header file is minimal, and only defines the types and macros that are

+  necessary for the OvmfPkg implementation.

+

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

+

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

+**/

+

+#ifndef VIRTIO_FS_H_

+#define VIRTIO_FS_H_

+

+#include <IndustryStandard/Virtio.h>

+

+//

+// Lowest numbered queue for sending normal priority requests.

+//

+#define VIRTIO_FS_REQUEST_QUEUE 1

+

+//

+// Number of bytes in the "VIRTIO_FS_CONFIG.Tag" field.

+//

+#define VIRTIO_FS_TAG_BYTES 36

+

+//

+// Device configuration layout.

+//

+#pragma pack (1)

+typedef struct {

+  //

+  // The Tag field can be considered the filesystem label, or a mount point

+  // hint. It is UTF-8 encoded, and padded to full size with NUL bytes. If the

+  // encoded bytes take up the entire Tag field, then there is no NUL

+  // terminator.

+  //

+  UINT8 Tag[VIRTIO_FS_TAG_BYTES];

+  //

+  // The total number of request virtqueues exposed by the device (i.e.,

+  // excluding the "hiprio" queue).

+  //

+  UINT32 NumReqQueues;

+} VIRTIO_FS_CONFIG;

+#pragma pack ()

+

+#endif // VIRTIO_FS_H_

diff --git a/OvmfPkg/VirtioFsDxe/DriverBinding.c b/OvmfPkg/VirtioFsDxe/DriverBinding.c
index 65e45b5c4b..b888158a80 100644
--- a/OvmfPkg/VirtioFsDxe/DriverBinding.c
+++ b/OvmfPkg/VirtioFsDxe/DriverBinding.c
@@ -6,7 +6,6 @@
   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

@@ -80,6 +79,17 @@ VirtioFsBindingStart (
     goto FreeVirtioFs;

   }

 

+  Status = VirtioFsInit (VirtioFs);

+  if (EFI_ERROR (Status)) {

+    goto CloseVirtio;

+  }

+

+  Status = gBS->CreateEvent (EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,

+                  VirtioFsExitBoot, VirtioFs, &VirtioFs->ExitBoot);

+  if (EFI_ERROR (Status)) {

+    goto UninitVirtioFs;

+  }

+

   VirtioFs->SimpleFs.Revision   = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION;

   VirtioFs->SimpleFs.OpenVolume = VirtioFsOpenVolume;

 

@@ -87,11 +97,18 @@ VirtioFsBindingStart (
                   &gEfiSimpleFileSystemProtocolGuid, EFI_NATIVE_INTERFACE,

                   &VirtioFs->SimpleFs);

   if (EFI_ERROR (Status)) {

-    goto CloseVirtio;

+    goto CloseExitBoot;

   }

 

   return EFI_SUCCESS;

 

+CloseExitBoot:

+  CloseStatus = gBS->CloseEvent (VirtioFs->ExitBoot);

+  ASSERT_EFI_ERROR (CloseStatus);

+

+UninitVirtioFs:

+  VirtioFsUninit (VirtioFs);

+

 CloseVirtio:

   CloseStatus = gBS->CloseProtocol (ControllerHandle,

                        &gVirtioDeviceProtocolGuid, This->DriverBindingHandle,

@@ -133,6 +150,11 @@ VirtioFsBindingStop (
     return Status;

   }

 

+  Status = gBS->CloseEvent (VirtioFs->ExitBoot);

+  ASSERT_EFI_ERROR (Status);

+

+  VirtioFsUninit (VirtioFs);

+

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

                   This->DriverBindingHandle, ControllerHandle);

   ASSERT_EFI_ERROR (Status);

diff --git a/OvmfPkg/VirtioFsDxe/Helpers.c b/OvmfPkg/VirtioFsDxe/Helpers.c
new file mode 100644
index 0000000000..7b4906c541
--- /dev/null
+++ b/OvmfPkg/VirtioFsDxe/Helpers.c
@@ -0,0 +1,299 @@
+/** @file

+  Initialization and helper routines for the Virtio Filesystem device.

+

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

+

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

+**/

+

+#include <Library/VirtioLib.h>           // Virtio10WriteFeatures()

+

+#include "VirtioFsDxe.h"

+

+/**

+  Read the Virtio Filesystem device configuration structure in full.

+

+  @param[in] Virtio   The Virtio protocol underlying the VIRTIO_FS object.

+

+  @param[out] Config  The fully populated VIRTIO_FS_CONFIG structure.

+

+  @retval EFI_SUCCESS  Config has been filled in.

+

+  @return              Error codes propagated from Virtio->ReadDevice(). The

+                       contents of Config are indeterminate.

+**/

+STATIC

+EFI_STATUS

+VirtioFsReadConfig (

+  IN  VIRTIO_DEVICE_PROTOCOL *Virtio,

+  OUT VIRTIO_FS_CONFIG       *Config

+  )

+{

+  UINTN      Idx;

+  EFI_STATUS Status;

+

+  for (Idx = 0; Idx < VIRTIO_FS_TAG_BYTES; Idx++) {

+    Status = Virtio->ReadDevice (

+                       Virtio,                                 // This

+                       OFFSET_OF (VIRTIO_FS_CONFIG, Tag[Idx]), // FieldOffset

+                       sizeof Config->Tag[Idx],                // FieldSize

+                       sizeof Config->Tag[Idx],                // BufferSize

+                       &Config->Tag[Idx]                       // Buffer

+                       );

+    if (EFI_ERROR (Status)) {

+      return Status;

+    }

+  }

+

+  Status = Virtio->ReadDevice (

+                     Virtio,                                     // This

+                     OFFSET_OF (VIRTIO_FS_CONFIG, NumReqQueues), // FieldOffset

+                     sizeof Config->NumReqQueues,                // FieldSize

+                     sizeof Config->NumReqQueues,                // BufferSize

+                     &Config->NumReqQueues                       // Buffer

+                     );

+  return Status;

+}

+

+/**

+  Configure the Virtio Filesystem device underlying VirtioFs.

+

+  @param[in,out] VirtioFs  The VIRTIO_FS object for which Virtio communication

+                           should be set up. On input, the caller is

+                           responsible for VirtioFs->Virtio having been

+                           initialized. On output, synchronous Virtio

+                           Filesystem commands (primitives) may be submitted to

+                           the device.

+

+  @retval EFI_SUCCESS      Virtio machinery has been set up.

+

+  @retval EFI_UNSUPPORTED  The host-side configuration of the Virtio Filesystem

+                           is not supported by this driver.

+

+  @return                  Error codes from underlying functions.

+**/

+EFI_STATUS

+VirtioFsInit (

+  IN OUT VIRTIO_FS *VirtioFs

+  )

+{

+  UINT8            NextDevStat;

+  EFI_STATUS       Status;

+  UINT64           Features;

+  VIRTIO_FS_CONFIG Config;

+  UINTN            Idx;

+  UINT64           RingBaseShift;

+

+  //

+  // Execute virtio-v1.1-cs01-87fa6b5d8155, 3.1.1 Driver Requirements: Device

+  // Initialization.

+  //

+  // 1. Reset the device.

+  //

+  NextDevStat = 0;

+  Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+

+  //

+  // 2. Set the ACKNOWLEDGE status bit [...]

+  //

+  NextDevStat |= VSTAT_ACK;

+  Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+

+  //

+  // 3. Set the DRIVER status bit [...]

+  //

+  NextDevStat |= VSTAT_DRIVER;

+  Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+

+  //

+  // 4. Read device feature bits...

+  //

+  Status = VirtioFs->Virtio->GetDeviceFeatures (VirtioFs->Virtio, &Features);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+  if ((Features & VIRTIO_F_VERSION_1) == 0) {

+    Status = EFI_UNSUPPORTED;

+    goto Failed;

+  }

+  //

+  // No device-specific feature bits have been defined in file "virtio-fs.tex"

+  // of the virtio spec at <https://github.com/oasis-tcs/virtio-spec.git>, as

+  // of commit 87fa6b5d8155.

+  //

+  Features &= VIRTIO_F_VERSION_1 | VIRTIO_F_IOMMU_PLATFORM;

+

+  //

+  // ... and write the subset of feature bits understood by the [...] driver to

+  // the device. [...]

+  // 5. Set the FEATURES_OK status bit.

+  // 6. Re-read device status to ensure the FEATURES_OK bit is still set [...]

+  //

+  Status = Virtio10WriteFeatures (VirtioFs->Virtio, Features, &NextDevStat);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+

+  //

+  // 7. Perform device-specific setup, including discovery of virtqueues for

+  // the device, [...] reading [...] the device's virtio configuration space

+  //

+  Status = VirtioFsReadConfig (VirtioFs->Virtio, &Config);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+

+  //

+  // 7.a. Convert the filesystem label from UTF-8 to UCS-2. Only labels with

+  // printable ASCII code points (U+0020 through U+007E) are supported.

+  // NUL-terminate at either the terminator we find, or right after the

+  // original label.

+  //

+  for (Idx = 0; Idx < VIRTIO_FS_TAG_BYTES && Config.Tag[Idx] != '\0'; Idx++) {

+    if (Config.Tag[Idx] < 0x20 || Config.Tag[Idx] > 0x7E) {

+      Status = EFI_UNSUPPORTED;

+      goto Failed;

+    }

+    VirtioFs->Label[Idx] = Config.Tag[Idx];

+  }

+  VirtioFs->Label[Idx] = L'\0';

+

+  //

+  // 7.b. We need one queue for sending normal priority requests.

+  //

+  if (Config.NumReqQueues < 1) {

+    Status = EFI_UNSUPPORTED;

+    goto Failed;

+  }

+

+  //

+  // 7.c. Fetch and remember the number of descriptors we can place on the

+  // queue at once. We'll need two descriptors per request, as a minimum --

+  // request header, response header.

+  //

+  Status = VirtioFs->Virtio->SetQueueSel (VirtioFs->Virtio,

+                               VIRTIO_FS_REQUEST_QUEUE);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+  Status = VirtioFs->Virtio->GetQueueNumMax (VirtioFs->Virtio,

+                               &VirtioFs->QueueSize);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+  if (VirtioFs->QueueSize < 2) {

+    Status = EFI_UNSUPPORTED;

+    goto Failed;

+  }

+

+  //

+  // 7.d. [...] population of virtqueues [...]

+  //

+  Status = VirtioRingInit (VirtioFs->Virtio, VirtioFs->QueueSize,

+             &VirtioFs->Ring);

+  if (EFI_ERROR (Status)) {

+    goto Failed;

+  }

+

+  Status = VirtioRingMap (VirtioFs->Virtio, &VirtioFs->Ring, &RingBaseShift,

+             &VirtioFs->RingMap);

+  if (EFI_ERROR (Status)) {

+    goto ReleaseQueue;

+  }

+

+  Status = VirtioFs->Virtio->SetQueueAddress (VirtioFs->Virtio,

+                               &VirtioFs->Ring, RingBaseShift);

+  if (EFI_ERROR (Status)) {

+    goto UnmapQueue;

+  }

+

+  //

+  // 8. Set the DRIVER_OK status bit.

+  //

+  NextDevStat |= VSTAT_DRIVER_OK;

+  Status = VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);

+  if (EFI_ERROR (Status)) {

+    goto UnmapQueue;

+  }

+

+  return EFI_SUCCESS;

+

+UnmapQueue:

+  VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio, VirtioFs->RingMap);

+

+ReleaseQueue:

+  VirtioRingUninit (VirtioFs->Virtio, &VirtioFs->Ring);

+

+Failed:

+  //

+  // If any of these steps go irrecoverably wrong, the driver SHOULD set the

+  // FAILED status bit to indicate that it has given up on the device (it can

+  // reset the device later to restart if desired). [...]

+  //

+  // Virtio access failure here should not mask the original error.

+  //

+  NextDevStat |= VSTAT_FAILED;

+  VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, NextDevStat);

+

+  return Status;

+}

+

+/**

+  De-configure the Virtio Filesystem device underlying VirtioFs.

+

+  @param[in] VirtioFs  The VIRTIO_FS object for which Virtio communication

+                       should be torn down. On input, the caller is responsible

+                       for having called VirtioFsInit(). On output, Virtio

+                       Filesystem commands (primitives) must no longer be

+                       submitted to the device.

+**/

+VOID

+VirtioFsUninit (

+  IN OUT VIRTIO_FS *VirtioFs

+  )

+{

+  //

+  // Resetting the Virtio device makes it release its resources and forget its

+  // configuration.

+  //

+  VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, 0);

+  VirtioFs->Virtio->UnmapSharedBuffer (VirtioFs->Virtio, VirtioFs->RingMap);

+  VirtioRingUninit (VirtioFs->Virtio, &VirtioFs->Ring);

+}

+

+/**

+  ExitBootServices event notification function for a Virtio Filesystem object.

+

+  This function resets the VIRTIO_FS.Virtio device, causing it to release all

+  references to guest-side resources. The function may only be called after

+  VirtioFsInit() returns successfully and before VirtioFsUninit() is called.

+

+  @param[in] ExitBootEvent   The VIRTIO_FS.ExitBoot event that has been

+                             signaled.

+

+  @param[in] VirtioFsAsVoid  Pointer to the VIRTIO_FS object, passed in as

+                             (VOID*).

+**/

+VOID

+EFIAPI

+VirtioFsExitBoot (

+  IN EFI_EVENT ExitBootEvent,

+  IN VOID      *VirtioFsAsVoid

+  )

+{

+  VIRTIO_FS *VirtioFs;

+

+  VirtioFs = VirtioFsAsVoid;

+  DEBUG ((DEBUG_VERBOSE, "%a: VirtioFs=0x%p Label=\"%s\"\n", __FUNCTION__,

+    VirtioFsAsVoid, VirtioFs->Label));

+  VirtioFs->Virtio->SetDeviceStatus (VirtioFs->Virtio, 0);

+}

diff --git a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
index 287defd21f..2aae96ecd7 100644
--- a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
+++ b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
@@ -11,13 +11,22 @@
 #define VIRTIO_FS_DXE_H_

 

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

+#include <IndustryStandard/VirtioFs.h> // VIRTIO_FS_TAG_BYTES

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

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

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

+#include <Uefi/UefiBaseType.h>         // EFI_EVENT

 

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

 

 //

+// Filesystem label encoded in UCS-2, transformed from the UTF-8 representation

+// in "VIRTIO_FS_CONFIG.Tag", and NUL-terminated. Only the printable ASCII code

+// points (U+0020 through U+007E) are supported.

+//

+typedef CHAR16 VIRTIO_FS_LABEL[VIRTIO_FS_TAG_BYTES + 1];

+

+//

 // Main context structure, expressing an EFI_SIMPLE_FILE_SYSTEM_PROTOCOL

 // interface on top of the Virtio Filesystem device.

 //

@@ -31,6 +40,11 @@ typedef struct {
   //                              -----------   ------------------  ----------

   UINT64                          Signature; // DriverBindingStart  0

   VIRTIO_DEVICE_PROTOCOL          *Virtio;   // DriverBindingStart  0

+  VIRTIO_FS_LABEL                 Label;     // VirtioFsInit        1

+  UINT16                          QueueSize; // VirtioFsInit        1

+  VRING                           Ring;      // VirtioRingInit      2

+  VOID                            *RingMap;  // VirtioRingMap       2

+  EFI_EVENT                       ExitBoot;  // DriverBindingStart  0

   EFI_SIMPLE_FILE_SYSTEM_PROTOCOL SimpleFs;  // DriverBindingStart  0

 } VIRTIO_FS;

 

@@ -38,6 +52,27 @@ typedef struct {
   CR (SimpleFsReference, VIRTIO_FS, SimpleFs, VIRTIO_FS_SIG);

 

 //

+// Initialization and helper routines for the Virtio Filesystem device.

+//

+

+EFI_STATUS

+VirtioFsInit (

+  IN OUT VIRTIO_FS *VirtioFs

+  );

+

+VOID

+VirtioFsUninit (

+  IN OUT VIRTIO_FS *VirtioFs

+  );

+

+VOID

+EFIAPI

+VirtioFsExitBoot (

+  IN EFI_EVENT ExitBootEvent,

+  IN VOID      *VirtioFsAsVoid

+  );

+

+//

 // EFI_SIMPLE_FILE_SYSTEM_PROTOCOL member functions for the Virtio Filesystem

 // driver.

 //

diff --git a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
index ff9b1c6178..f6eebdb6bc 100644
--- a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
+++ b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
@@ -82,6 +82,7 @@
 

 [Sources]

   DriverBinding.c

+  Helpers.c

   SimpleFsOpenVolume.c

   VirtioFsDxe.h

 

@@ -91,6 +92,7 @@
   MemoryAllocationLib

   UefiBootServicesTableLib

   UefiDriverEntryPoint

+  VirtioLib

 

 [Protocols]

   gEfiComponentName2ProtocolGuid        ## PRODUCES