Re: [Qemu-devel] [PATCH 2/6] Revert "vhost-net: tell tap backend about the vnet endianness"

[Greg Kurz]

On Thu, 7 Jan 2016 20:52:04 +0100
Laurent Vivier  wrote:

> 
> 
> On 07/01/2016 12:32, Greg Kurz wrote:
> > This reverts commit 5be7d9f1b1452613b95c6ba70b8d7ad3d0797991.
> > 
> > Cross-endian is now configured by the core virtio-net code. We simply
> > fall back on full emulation if the net backend cannot support the
> > requested endianness for vnet headers.
> > 
> > Signed-off-by: Greg Kurz 
> > ---
> >  hw/net/vhost_net.c  |   33 +
> >  hw/net/virtio-net.c |7 +++
> >  2 files changed, 8 insertions(+), 32 deletions(-)
> > 
> > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > index 318c3e6ad213..0c7362b7a772 100644
> > --- a/hw/net/vhost_net.c
> > +++ b/hw/net/vhost_net.c
> > @@ -38,7 +38,6 @@
> >  #include "standard-headers/linux/virtio_ring.h"
> >  #include "hw/virtio/vhost.h"
> >  #include "hw/virtio/virtio-bus.h"
> > -#include "hw/virtio/virtio-access.h"
> >  
> >  struct vhost_net {
> >  struct vhost_dev dev;
> > @@ -199,27 +198,6 @@ static void vhost_net_set_vq_index(struct vhost_net 
> > *net, int vq_index)
> >  net->dev.vq_index = vq_index;
> >  }
> >  
> > -static int vhost_net_set_vnet_endian(VirtIODevice *dev, NetClientState 
> > *peer,
> > - bool set)
> > -{
> > -int r = 0;
> > -
> > -if (virtio_vdev_has_feature(dev, VIRTIO_F_VERSION_1) ||
> > -(virtio_legacy_is_cross_endian(dev) && 
> > !virtio_is_big_endian(dev))) {
> > -r = qemu_set_vnet_le(peer, set);
> > -if (r) {
> > -error_report("backend does not support LE vnet headers");
> > -}
> > -} else if (virtio_legacy_is_cross_endian(dev)) {
> > -r = qemu_set_vnet_be(peer, set);
> > -if (r) {
> > -error_report("backend does not support BE vnet headers");
> > -}
> > -}
> > -
> > -return r;
> > -}
> > -
> >  static int vhost_net_start_one(struct vhost_net *net,
> > VirtIODevice *dev)
> >  {
> > @@ -308,11 +286,6 @@ int vhost_net_start(VirtIODevice *dev, NetClientState 
> > *ncs,
> >  goto err;
> >  }
> >  
> > -r = vhost_net_set_vnet_endian(dev, ncs[0].peer, true);
> > -if (r < 0) {
> > -goto err;
> > -}
> > -
> >  for (i = 0; i < total_queues; i++) {
> >  vhost_net_set_vq_index(get_vhost_net(ncs[i].peer), i * 2);
> >  }
> > @@ -320,7 +293,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState 
> > *ncs,
> >  r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
> >  if (r < 0) {
> >  error_report("Error binding guest notifier: %d", -r);
> > -goto err_endian;
> > +goto err;
> >  }
> >  
> >  for (i = 0; i < total_queues; i++) {
> > @@ -342,8 +315,6 @@ err_start:
> >  fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", e);
> >  fflush(stderr);
> >  }
> > -err_endian:
> > -vhost_net_set_vnet_endian(dev, ncs[0].peer, false);
> >  err:
> >  return r;
> >  }
> > @@ -366,8 +337,6 @@ void vhost_net_stop(VirtIODevice *dev, NetClientState 
> > *ncs,
> >  fflush(stderr);
> >  }
> >  assert(r >= 0);
> > -
> > -assert(vhost_net_set_vnet_endian(dev, ncs[0].peer, false) >= 0);
> >  }
> >  
> >  void vhost_net_cleanup(struct vhost_net *net)
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index d4cc94ea5e55..5a0ab6ad5bb5 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -128,6 +128,13 @@ static void virtio_net_vhost_status(VirtIONet *n, 
> > uint8_t status)
> >  if (!n->vhost_started) {
> >  int r, i;
> >  
> > +if (n->needs_vnet_hdr_swap) {
> > +error_report("backend does not support %s vnet headers."
> > + "falling back on userspace virtio",
> > + virtio_is_big_endian(vdev) ? "BE" : "LE");
> > +return;
> > +}
> > +
> 
> This is not part of the revert, perhaps this can go in PATCH 1/6 ?
> In virtio_net_vnet_status() ?
> 

Makes sense. I'll fix that.

> >  /* Any packets outstanding? Purge them to avoid touching rings
> >   * when vhost is running.
> >   */
> > 
> > 
> 

Re: [Qemu-devel] [PATCH 2/6] Revert "vhost-net: tell tap backend about the vnet endianness"

[Cornelia Huck]

On Fri, 8 Jan 2016 11:26:05 +0100
Greg Kurz  wrote:

> On Fri, 8 Jan 2016 11:11:20 +0100
> Cornelia Huck  wrote:
> 
> > On Thu, 07 Jan 2016 12:32:08 +0100
> > Greg Kurz  wrote:

> > > + "falling back on userspace virtio",
> > 
> > s/on/to/
> > 
> > ?
> > 
> 
> I thought the same but...
> 
> http://idioms.thefreedictionary.com/fall+back+on

Then I'd vote for "onto" :)

Re: [Qemu-devel] [PATCH 2/6] Revert "vhost-net: tell tap backend about the vnet endianness"

[Cornelia Huck]

On Thu, 07 Jan 2016 12:32:08 +0100
Greg Kurz  wrote:

> This reverts commit 5be7d9f1b1452613b95c6ba70b8d7ad3d0797991.
> 
> Cross-endian is now configured by the core virtio-net code. We simply
> fall back on full emulation if the net backend cannot support the
> requested endianness for vnet headers.
> 
> Signed-off-by: Greg Kurz 
> ---
>  hw/net/vhost_net.c  |   33 +
>  hw/net/virtio-net.c |7 +++
>  2 files changed, 8 insertions(+), 32 deletions(-)

> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index d4cc94ea5e55..5a0ab6ad5bb5 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -128,6 +128,13 @@ static void virtio_net_vhost_status(VirtIONet *n, 
> uint8_t status)
>  if (!n->vhost_started) {
>  int r, i;
> 
> +if (n->needs_vnet_hdr_swap) {
> +error_report("backend does not support %s vnet headers."

s/./;/

> + "falling back on userspace virtio",

s/on/to/

?

> + virtio_is_big_endian(vdev) ? "BE" : "LE");
> +return;
> +}
> +
>  /* Any packets outstanding? Purge them to avoid touching rings
>   * when vhost is running.
>   */
> 
> 

Re: [Qemu-devel] [PATCH 2/6] Revert "vhost-net: tell tap backend about the vnet endianness"

[Greg Kurz]

On Fri, 8 Jan 2016 11:11:20 +0100
Cornelia Huck  wrote:

> On Thu, 07 Jan 2016 12:32:08 +0100
> Greg Kurz  wrote:
> 
> > This reverts commit 5be7d9f1b1452613b95c6ba70b8d7ad3d0797991.
> > 
> > Cross-endian is now configured by the core virtio-net code. We simply
> > fall back on full emulation if the net backend cannot support the
> > requested endianness for vnet headers.
> > 
> > Signed-off-by: Greg Kurz 
> > ---
> >  hw/net/vhost_net.c  |   33 +
> >  hw/net/virtio-net.c |7 +++
> >  2 files changed, 8 insertions(+), 32 deletions(-)
> 
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index d4cc94ea5e55..5a0ab6ad5bb5 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -128,6 +128,13 @@ static void virtio_net_vhost_status(VirtIONet *n, 
> > uint8_t status)
> >  if (!n->vhost_started) {
> >  int r, i;
> > 
> > +if (n->needs_vnet_hdr_swap) {
> > +error_report("backend does not support %s vnet headers."
> 
> s/./;/
> 

I'll fix that.

> > + "falling back on userspace virtio",
> 
> s/on/to/
> 
> ?
> 

I thought the same but...

http://idioms.thefreedictionary.com/fall+back+on

> > + virtio_is_big_endian(vdev) ? "BE" : "LE");
> > +return;
> > +}
> > +
> >  /* Any packets outstanding? Purge them to avoid touching rings
> >   * when vhost is running.
> >   */
> > 
> > 
>