Re: [Qemu-devel] [PATCH 1/2] dataplane: drop copy_in_vring_desc()

[Cornelia Huck]

On Fri, 26 Jun 2015 09:32:21 +0200
Greg Kurz <address@hidden> wrote:

> During early virtio 1.0 devel, there were several proposals about how to
> deal with the 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 boot in SLOF (BE client) when host is ppc64le with the following
> QEMU 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 result in a smaller patch.

I'd prefer the revert, as the resulting code is nicer IMHO.

But your second patch should apply regardless.

> 
> This patch allows SLOF to boot the OS.
> 
> Signed-off-by: Greg Kurz <address@hidden>
> ---
>  hw/virtio/dataplane/vring.c |   14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)