Re: [Qemu-devel] [PATCH] dataplane: drop copy_in_vring_desc()

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

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On Fri, 26 Jun 2015 11:00:45 +0100
Stefan Hajnoczi <stefanha@gmail.com> wrote:

> On Thu, Jun 25, 2015 at 05:26:09PM +0200, Greg Kurz wrote:
> > During early virtio 1.0 devel, there were several proposals about how to
> > deal endianness of the vring descriptor fields:
> > - convert the decriptor to host endianness in a single place, and use its
> >   fields directly in the code
> > - keep the descriptor untouched and use virtio memory helpers to access its
> >   fields with the appropriate endianness
> > 
> > It seems like both approaches got merged: commit f5a5628cf0b6 introduces
> > an extra swap that negates the one brought by commit b0e5d90ebc3e. This
> > breaks cross-endian setups with the following error:
> > 
> > Failed to map descriptor addr 0x18e2517e00000000 len 268435456
> > 
> > A solution could be to revert f5a5628cf0b6, but dropping copy_in_vring_desc()
> > is equivalent and gives a smaller patch.
> 
> Cornelia already sent "[PATCH] Revert "dataplane: allow virtio-1
> devices" to revert f5a5628cf0b.  I acked it but the patch is going
> through Michael Tsirkin.

Indeed... my bad, I overlooked that thread...

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G

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