Re: [PATCH v3 4/6] virtio-net: expose virtio_net_supported_guest_offloads()

[Eugenio Perez Martin]

On Thu, Jun 1, 2023 at 3:49 PM Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> To support restoring offloads state in vdpa, need to expose
> the function virtio_net_supported_guest_offloads().
> QEMU uses this function to get the guest supported offloads
> and no needs to send the corresponding CVQ command if guest

doesn't need to send?

> enables all supported features.
>

Good! I'd add the same message as the next patch's comment, to signal
it is because the device has already enabled by default:

+         * According to VirtIO standard, "Upon feature negotiation
+         * corresponding offload gets enabled to preserve
+         * backward compatibility."
+         * So we do not need to send this CVQ command if the guest
+         * also enables all supported offloads.

Thanks!


> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---
>  hw/net/virtio-net.c            | 2 +-
>  include/hw/virtio/virtio-net.h | 1 +
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 7b27dad6c4..7e8897a8bc 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -874,7 +874,7 @@ static uint64_t 
> virtio_net_guest_offloads_by_features(uint32_t features)
>      return guest_offloads_mask & features;
>  }
>
> -static inline uint64_t virtio_net_supported_guest_offloads(const VirtIONet 
> *n)
> +uint64_t virtio_net_supported_guest_offloads(const VirtIONet *n)
>  {
>      VirtIODevice *vdev = VIRTIO_DEVICE(n);
>      return virtio_net_guest_offloads_by_features(vdev->guest_features);
> diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
> index ef234ffe7e..5f5dcb4572 100644
> --- a/include/hw/virtio/virtio-net.h
> +++ b/include/hw/virtio/virtio-net.h
> @@ -227,5 +227,6 @@ size_t virtio_net_handle_ctrl_iov(VirtIODevice *vdev,
>                                    unsigned out_num);
>  void virtio_net_set_netclient_name(VirtIONet *n, const char *name,
>                                     const char *type);
> +uint64_t virtio_net_supported_guest_offloads(const VirtIONet *n);
>
>  #endif
> --
> 2.25.1
>