OvmfPkg/VirtioFsDxe: implement EFI_FILE_PROTOCOL.Write()

Using the functions introduced previously, we can now implement
VirtioFsSimpleFileWrite().

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: <20201216211125.19496-40-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

diff --git a/OvmfPkg/VirtioFsDxe/SimpleFsWrite.c b/OvmfPkg/VirtioFsDxe/SimpleFsWrite.c
index 90d82bd722b1c8d67c1a6f234765b5af8034425e..8ae317c88e43c184af87c7baf883040f1b02bf1d 100644 (file)
--- a/OvmfPkg/VirtioFsDxe/SimpleFsWrite.c
+++ b/OvmfPkg/VirtioFsDxe/SimpleFsWrite.c
@@ -16,5 +16,66 @@ VirtioFsSimpleFileWrite (
   IN     VOID              *Buffer\r
   )\r
 {\r
-  return EFI_NO_MEDIA;\r
+  VIRTIO_FS_FILE *VirtioFsFile;\r
+  VIRTIO_FS      *VirtioFs;\r
+  EFI_STATUS     Status;\r
+  UINTN          Transferred;\r
+  UINTN          Left;\r
+\r
+  VirtioFsFile = VIRTIO_FS_FILE_FROM_SIMPLE_FILE (This);\r
+  VirtioFs     = VirtioFsFile->OwnerFs;\r
+\r
+  if (VirtioFsFile->IsDirectory) {\r
+    return EFI_UNSUPPORTED;\r
+  }\r
+  if (!VirtioFsFile->IsOpenForWriting) {\r
+    return EFI_ACCESS_DENIED;\r
+  }\r
+\r
+  Status      = EFI_SUCCESS;\r
+  Transferred = 0;\r
+  Left        = *BufferSize;\r
+  while (Left > 0) {\r
+    UINT32 WriteSize;\r
+\r
+    //\r
+    // Honor the write buffer size limit.\r
+    //\r
+    WriteSize = (UINT32)MIN ((UINTN)VirtioFs->MaxWrite, Left);\r
+    Status = VirtioFsFuseWrite (\r
+               VirtioFs,\r
+               VirtioFsFile->NodeId,\r
+               VirtioFsFile->FuseHandle,\r
+               VirtioFsFile->FilePosition + Transferred,\r
+               &WriteSize,\r
+               (UINT8 *)Buffer + Transferred\r
+               );\r
+    if (!EFI_ERROR (Status) && WriteSize == 0) {\r
+      //\r
+      // Progress should have been made.\r
+      //\r
+      Status = EFI_DEVICE_ERROR;\r
+    }\r
+    if (EFI_ERROR (Status)) {\r
+      break;\r
+    }\r
+    Transferred += WriteSize;\r
+    Left        -= WriteSize;\r
+  }\r
+\r
+  *BufferSize = Transferred;\r
+  VirtioFsFile->FilePosition += Transferred;\r
+  //\r
+  // According to the UEFI spec,\r
+  //\r
+  // - 'Partial writes only occur when there has been a data error during the\r
+  //    write attempt (such as "file space full")', and\r
+  //\r
+  // - (as an example) EFI_VOLUME_FULL is returned when 'The volume is full'.\r
+  //\r
+  // These together imply that after a partial write, we have to return an\r
+  // error. In other words, (Transferred > 0) is inconsequential for the return\r
+  // value.\r
+  //\r
+  return Status;\r
 }\r