Re: [Qemu-devel] buffer alignment for block backends

[Samuel Thibault]

Gerd Hoffmann, le Thu 09 Apr 2009 15:54:34 +0200, a écrit :
> On 04/09/09 15:30, Stefano Stabellini wrote:
> >The userspace\kernelspace distinction does not make much sense in
> >minios, but yes it provides an interface to communicate with blkback in
> >dom0. This interface is used by block-vbd in qemu instead of
> >block-raw-posix when run in minios.
> 
> Sit back, look again.  Do you really need it being page-aligned?

Page aligned is an optimization which comes for free when you can
already choose the alignment.

> The xen block protocol can handle unaligned requests just fine.

Not completely arbitrarily aligned requests. They need to be
sector-aligned.

Samuel