Hi all,
the main issue with stubdoms at the moment is that the new dma api does
not support an upper limit for the number of sectors in a single dma
transfer.
This means that block-vbd can issue blkfront_aio transfers that exceed
the blktap limit BLKIF_MAX_SEGMENTS_PER_REQUEST.
The attached qemu patch makes block-vbd split any request bigger than
the limit above.
The small xen patch is also needed to change struct blkfront_aiocb.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>