[Qemu-devel] [PULL 17/23] virtio-blk: reject configs with logical block size > physical block size

[Stefan Hajnoczi <stefanha@redhat.com>]

From: Mark Kanda <mark.kanda@oracle.com>

virtio-blk logical block size should never be larger than physical block
size because it doesn't make sense to have such configurations. QEMU doesn't
have a way to effectively express this condition; the best it can do is
report the physical block exponent as 0 - indicating the logical block size
equals the physical block size.

This is identical to commit 3da023b5827543ee4c022986ea2ad9d1274410b2
but applied to virtio-blk (instead of virtio-scsi).

Signed-off-by: Mark Kanda <mark.kanda@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Ameya More <ameya.more@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 773169891f9f2deb4cb7c4ef2655580dbe24c1d1.1513005190.git.mark.kanda@oracle.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/virtio-blk.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index d8cfdc81f6..58a5def75d 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -948,6 +948,13 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
 
     blkconf_blocksizes(&conf->conf);
 
+    if (conf->conf.logical_block_size >
+        conf->conf.physical_block_size) {
+        error_setg(errp,
+                   "logical_block_size > physical_block_size not supported");
+        return;
+    }
+
     virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
                 sizeof(struct virtio_blk_config));
 
-- 
2.14.3