Hi Maxime, > -----Original Message----- > From: Maxime Coquelin [mailto:maxime.coque...@redhat.com] > Sent: Tuesday, February 6, 2018 10:24 PM > To: Wang, Xiao W <xiao.w.w...@intel.com>; dev@dpdk.org > Cc: Tan, Jianfeng <jianfeng....@intel.com>; Bie, Tiwei <tiwei....@intel.com>; > y...@fridaylinux.org; Liang, Cunming <cunming.li...@intel.com>; Daly, Dan > <dan.d...@intel.com>; Wang, Zhihong <zhihong.w...@intel.com> > Subject: Re: [PATCH 2/3] net/vdpa_virtio_pci: introduce vdpa sample driver > > 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.w...@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?
The existing vfio code doesn't fit VDPA well, this vDPA driver needs to program IOMMU for a vDPA device with a VM's memory table. While the eal/vfio uses a struct vfio_cfg to takes all regular devices and add them to a single vfio_container, and program IOMMU with DPDK process's memory table. This driver doing PCI VFIO initialization itself can avoid affecting the global vfio_cfg structure. > > Wouldn't it be better (if possible) to use RTE_PMD_REGISTER_PCI() & co. > to benefit from all the existing infrastructure? RTE_PMD_REGISTER_PCI() & co will make this driver as PCI driver (physical device), then this will conflict with the virtio_pmd. So I make vDPA device driver as a vdev driver. > > Maxime Thanks for the comments, Xiao
