On Sun, 28 Jun 2015 15:03:20 +0200 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Fri, Jun 26, 2015 at 07:05:07PM +0200, Greg Kurz wrote: > > On Fri, 26 Jun 2015 18:28:42 +0200 > > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > > > > On Fri, Jun 26, 2015 at 02:18:38PM +0200, Greg Kurz wrote: > > > > On Fri, 26 Jun 2015 12:28:45 +0200 > > > > Cornelia Huck <cornelia.h...@de.ibm.com> wrote: > > > > > > > > > On Fri, 26 Jun 2015 09:32:21 +0200 > > > > > Greg Kurz <gk...@linux.vnet.ibm.com> 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. > > > > > > > > > > > > > Agreed. It is good to clear the endianness noise out of the real code. > > > > :) > > > > > > Can you please send v2 that works the way you want it? > > > > > > > Taken from a previous mail by Stefan: > > > > "Cornelia already sent "[PATCH] Revert "dataplane: allow virtio-1 > > devices" to revert f5a5628cf0b. I acked it but the patch is going > > through Michael Tsirkin." > > > > I guess you just have to take Cornelia's patch + Stefan's ack, > > and patch 2/2 in my series + Cornelia's rb, and we are all set. :) > > > > FWIW I tested and it works exactly the same. > > Sounds good. > Can you please test the pci branch from my tree, and confirm? > Sure ! I shall do it tomorrow. Thanks. -- Greg > > > > > > > But your second patch should apply regardless. > > > > > > > > > > > > > Thanks for your feedback. > > > > > > > > > > > > > > > > This patch allows SLOF to boot the OS. > > > > > > > > > > > > Signed-off-by: Greg Kurz <gk...@linux.vnet.ibm.com> > > > > > > --- > > > > > > hw/virtio/dataplane/vring.c | 14 ++------------ > > > > > > 1 file changed, 2 insertions(+), 12 deletions(-) > > > >
