On Tue, 20 Jan 2015 10:43:31 +0000
Stefan Hajnoczi [off-list ref] wrote:

On Thu, Dec 11, 2014 at 02:25:10PM +0100, Cornelia Huck wrote:

quoted

Handle endianness conversion for virtio-1 virtqueues correctly.

Note that dataplane now needs to be built per-target.

Signed-off-by: Cornelia Huck <redacted>
---
 hw/block/dataplane/virtio-blk.c               |    4 +-
 hw/scsi/virtio-scsi-dataplane.c               |    2 +-
 hw/virtio/Makefile.objs                       |    2 +-
 hw/virtio/dataplane/Makefile.objs             |    2 +-
 hw/virtio/dataplane/vring.c                   |   86 ++++++++++++++-----------
 include/hw/virtio/dataplane/vring-accessors.h |   75 +++++++++++++++++++++
 include/hw/virtio/dataplane/vring.h           |   14 +---
 7 files changed, 131 insertions(+), 54 deletions(-)
 create mode 100644 include/hw/virtio/dataplane/vring-accessors.h

This patch is independent of VIRTIO 1.0 and can be merged separately
(faster).

Yep, I've pulled it in front of my queue.

quoted

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 1222a37..2d8cc15 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c

@@ -16,7 +16,9 @@
 #include "qemu/iov.h"
 #include "qemu/thread.h"
 #include "qemu/error-report.h"
+#include "hw/virtio/virtio-access.h"
 #include "hw/virtio/dataplane/vring.h"
+#include "hw/virtio/dataplane/vring-accessors.h"

I like your vring-accessors.h approach better than the inline
virtio_ld/st_p() in my patch.  Nice.

quoted

@@ -154,15 +157,18 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
 }
 
 
-static int get_desc(Vring *vring, VirtQueueElement *elem,
+static int get_desc(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
                     struct vring_desc *desc)

Since we copy in struct vring_desc anyway, it's cleaner to byteswap the
fields once instead of remembering to do it each time we need to access
a field.  The copy_in_vring_desc() function is one thing I prefer I
about my patch.

Agreed, that makes the code cleaner.

I've prepared a version of this patch using copy_in_vring_desc() and
I'll post it when it survives some light testing on my side.