[Qemu-devel] [PATCH 4/4] Add virtio disk identification support

[john cooper <john.cooper@redhat.com>]

Return serial string to the guest application via
ioctl driver call.

Note this form of interface to the guest userland
was the consensus when the prior version using
the ATA_IDENTIFY came under dispute.

Signed-off-by: john cooper <john.cooper@redhat.com>
---

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index cd66806..0954193 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -225,6 +225,21 @@ static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
 	struct gendisk *disk = bdev->bd_disk;
 	struct virtio_blk *vblk = disk->private_data;
 
+	if (cmd == 'VBID') {
+		void *usr_data = (void __user *)data;
+		char *id_str;
+		int err;
+
+		if (!(id_str = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL)))
+			err = -ENOMEM;
+		else if ((err = virtblk_get_id(disk, id_str)))
+			;
+		else if (copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))
+			err = -EFAULT;
+		if (id_str)
+			kfree(id_str);
+		return err;
+	}
 	/*
 	 * Only allow the generic SCSI ioctls if the host can support it.
 	 */
-- 
john.cooper@redhat.com