[dpdk-dev] [PATCH 2/3] net/vdpa_virtio_pci: introduce vdpa sample driver

[Maxime Coquelin]

Hi Xiao,

On 02/04/2018 03:55 PM, Xiao Wang wrote:
> This driver is a reference sample of making vDPA device driver based
> on vhost lib, this driver uses a standard virtio-net PCI device as
> vDPA device, it can serve as a backend for a virtio-net pci device
> in nested VM.
> 
> The key driver ops implemented are:
> 
> * vdpa_virtio_eng_init
> Mapping virtio pci device with VFIO into userspace, and read device
> capability and intialize internal data.
> 
> * vdpa_virtio_eng_uninit
> Release the mapped device.
> 
> * vdpa_virtio_info_query
> Device capability reporting, e.g. queue number, features.
> 
> * vdpa_virtio_dev_config
> With the guest virtio information provideed by vhost lib, this
> function configures device and IOMMU to set up vhost datapath,
> which includes: Rx/Tx vring, VFIO interrupt, kick relay.
> 
> * vdpa_virtio_dev_close
> Unset the stuff that are configured previously by dev_conf.
> 
> This driver requires the virtio device supports VIRTIO_F_IOMMU_PLATFORM
> , because the buffer address written in desc is IOVA.
> 
> Because vDPA driver needs to set up MSI-X vector to interrupt the guest,
> only vfio-pci is supported currently.
> 
> Signed-off-by: Xiao Wang<xiao.w.wang at intel.com>
> ---
>   config/common_base                                 |    6 +
>   config/common_linuxapp                             |    1 +
>   drivers/net/Makefile                               |    1 +
>   drivers/net/vdpa_virtio_pci/Makefile               |   31 +
>   .../net/vdpa_virtio_pci/rte_eth_vdpa_virtio_pci.c  | 1527 ++++++++++++++++++++
>   .../rte_vdpa_virtio_pci_version.map                |    4 +
>   mk/rte.app.mk                                      |    1 +
>   7 files changed, 1571 insertions(+)
>   create mode 100644 drivers/net/vdpa_virtio_pci/Makefile
>   create mode 100644 drivers/net/vdpa_virtio_pci/rte_eth_vdpa_virtio_pci.c
>   create mode 100644 drivers/net/vdpa_virtio_pci/rte_vdpa_virtio_pci_version.map

Is there a specific constraint that makes you expose PCI functions and
duplicate a lot of vfio code into the driver?

Wouldn't it be better (if possible) to use RTE_PMD_REGISTER_PCI() & co. 
to benefit from all the existing infrastructure?

Maxime