Re: [Qemu-devel] [RFC v2 2/2] virtio-net: Example Patch for using BPF

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jun 25, 2018 at 02:07:06PM +0300, Sameeh Jubran wrote:
> From: Sameeh Jubran <sjubran@redhat.com>
> 
> This commit is a sample only for using the libbpf in the code and
> shouldn't be committed.
> 
> Signed-off-by: Sameeh Jubran <sjubran@redhat.com>
> ---
>  hw/net/Makefile.objs | 4 ++++
>  hw/net/virtio-net.c  | 4 ++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/hw/net/Makefile.objs b/hw/net/Makefile.objs
> index fa461d4463..0fb271436d 100644
> --- a/hw/net/Makefile.objs
> +++ b/hw/net/Makefile.objs
> @@ -37,6 +37,10 @@ obj-$(CONFIG_PSERIES) += spapr_llan.o
>  obj-$(CONFIG_XILINX_ETHLITE) += xilinx_ethlite.o
>  
>  obj-$(CONFIG_VIRTIO_NET) += virtio-net.o
> +ifeq ($(CONFIG_BPF),y)
> +	virtio-net.o-cflags := $(CFLAGS_BPF)
> +	virtio-net.o-libs := $(LIBS_BPF)
> +endif
>  obj-y += vhost_net.o
>  
>  obj-$(CONFIG_ETSEC) += fsl_etsec/etsec.o fsl_etsec/registers.o \
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 90502fca7c..b4840838c1 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -27,6 +27,7 @@
>  #include "hw/virtio/virtio-access.h"
>  #include "migration/misc.h"
>  #include "standard-headers/linux/ethtool.h"
> +#include "standard-headers/linux/libbpf.h"
>  
>  #define VIRTIO_NET_VM_VERSION    11
>  
> @@ -1329,6 +1330,9 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
>      VirtQueueElement *elem;
>      int32_t num_packets = 0;
>      int queue_index = vq2q(virtio_get_queue_index(q->tx_vq));
> +
> +    struct bpf_object *obj = NULL;
> +    bpf_object__load(obj);

This really doesn't tell us anything useful about how this will be
used and integrated in qemu. I'd expect this patch to actually
be doing a real feature complete impl of RSS for virtio-net.

Regards,
Daniel
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