Re: [PATCH] virtio-net: enable SRIOV

[Jason Wang <jasowang@redhat.com>]

在 2021/4/26 下午6:21, Arkadiusz Kudan 写道:
> With increasing interest for virtio, NIC have appeared that provide
> SRIOV with PF appearing in the host as a virtio network device
> and probably more similiar NICs will emerge.
> igb_uio of DPDK or pci-pf-stub can be used to provide SRIOV,
> however there are hypervisors/VMMs that require VFs, which are
> to be PCI passthrued to a VM, to have its PF with network
> representation in the kernel. For virtio-net based PFs,
> virtio-net could do that by providing both SRIOV interface and
> netdev representation.
>
> Enable SRIOV via VIRTIO_F_SR_IOV feature bit if the device
> supports it.
>
> Signed-off-by: Arkadiusz Kudan <arkadiusz.kudan@codilime.com>
> Signed-off-by: Miroslaw Walukiewicz <Miroslaw.Walukiewicz@intel.com>
> ---
>   drivers/net/virtio_net.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0824e6999e49..a03aa7e99689 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3249,6 +3249,7 @@ static struct virtio_device_id id_table[] = {
>   
>   static unsigned int features[] = {
>   	VIRTNET_FEATURES,
> +	VIRTIO_F_SR_IOV,
>   };


So I'm suprised that it needs to be enabled per device. We had:

static void vp_transport_features(struct virtio_device *vdev, u64 features)
{
         struct virtio_pci_device *vp_dev = to_vp_device(vdev);
         struct pci_dev *pci_dev = vp_dev->pci_dev;

         if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
                         pci_find_ext_capability(pci_dev, 
PCI_EXT_CAP_ID_SRIOV))
                 __virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
}

And I had used this driver for SRIOV virtio-pci hardware for more than 
one year.

Thanks


>   
>   static unsigned int features_legacy[] = {