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

[Stefan Hajnoczi]

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.

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