OvmfPkg/VirtioFsDxe: submit the FUSE_INIT request to the device

Submit the FUSE_INIT request to the Virtio Filesystem device, for starting
the FUSE session.

The FUSE_INIT request is logged by the virtio-fs daemon, with this patch
applied, when (for example) using the "CONNECT" UEFI shell command.

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: <20201216211125.19496-9-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

OvmfPkg/VirtioFsDxe/Helpers.c

@@ -721,7 +721,8 @@ Unmap:
                           to send.
 
   @param[in] NodeId       The inode number of the file that the request refers
-                          to.
+                          to. When Opcode is VirtioFsFuseOpInit, NodeId is
+                          ignored by the Virtio Filesystem device.
 
   @retval EFI_INVALID_PARAMETER  RequestSize is smaller than
                                  sizeof(VIRTIO_FS_FUSE_REQUEST).
@@ -737,7 +738,7 @@ VirtioFsFuseNewRequest (
   IN OUT VIRTIO_FS              *VirtioFs,
      OUT VIRTIO_FS_FUSE_REQUEST *Request,
   IN     UINT32                 RequestSize,
-  IN     UINT32                 Opcode,
+  IN     VIRTIO_FS_FUSE_OPCODE  Opcode,
   IN     UINT64                 NodeId
   )
 {