virtio: add virtio disk geometry feature
Rather than faking up some geometry, allow the backend to push the disk
geometry via virtio pci config option. Keep the old geo code around for
compatibility.
Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (modified to single struct)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 78be6b8..84e064f 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -157,10 +157,25 @@
/* We provide getgeo only to please some old bootloader/partitioning tools */
static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
{
- /* some standard values, similar to sd */
- geo->heads = 1 << 6;
- geo->sectors = 1 << 5;
- geo->cylinders = get_capacity(bd->bd_disk) >> 11;
+ struct virtio_blk *vblk = bd->bd_disk->private_data;
+ struct virtio_blk_geometry vgeo;
+ int err;
+
+ /* see if the host passed in geometry config */
+ err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
+ offsetof(struct virtio_blk_config, geometry),
+ &vgeo);
+
+ if (!err) {
+ geo->heads = vgeo.heads;
+ geo->sectors = vgeo.sectors;
+ geo->cylinders = vgeo.cylinders;
+ } else {
+ /* some standard values, similar to sd */
+ geo->heads = 1 << 6;
+ geo->sectors = 1 << 5;
+ geo->cylinders = get_capacity(bd->bd_disk) >> 11;
+ }
return 0;
}
@@ -310,6 +325,7 @@
static unsigned int features[] = {
VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
+ VIRTIO_BLK_F_GEOMETRY,
};
static struct virtio_driver virtio_blk = {