On 2025/2/5 23:45, Thomas Monjalon wrote: > 05/02/2025 16:37, Renyong Wan: >> On 2025/2/5 22:43, Thomas Monjalon wrote: >>> 05/02/2025 15:37, Renyong Wan: >>>> On 2025/2/5 19:44, Thomas Monjalon wrote: >>>>> 28/01/2025 15:46, Renyong Wan: >>>>>> XSC PMD is designed to support both VFIO and private kernel drivers. >>>>> What's the benefit of private kernel drivers? >>>>> Why are they private? >>>> Hello Thomas, >>>> >>>> Thanks for your review. >>>> >>>> It can support the bifurcation model without unbinding the kernel >>>> driver, by utilizing our private kernel driver in conjunction with >>>> rdma-core. Currently, our kernel driver is not open-source, so it is >>>> considered a private kernel driver. This patch series only supports the >>>> VFIO driver. Our kernel driver is currently in the process of being >>>> open-sourced on kernel.org, and once it is available there, we also plan >>>> to submit the code that supports our kernel driver to DPDK. >>> OK that's interesting, thank you. >>> >>> I think it would be the first DPDK driver to support both VFIO or >>> bifurcated model. >>> How will we choose which one to use? With devargs? >>> >>> >> That's how we designed it. >> We designed a low-level device operations framework named xsc_dev_ops to >> support both VFIO drivers and kernel drivers. Each xsc_dev_ops is >> registered before the main function runs. During the PCI device probe >> phase, the XSC PMD selects the corresponding xsc_dev_ops based on >> rte_pci_device->driver, therefore, there is no need for devargs. > I don't understand. > If both VFIO and the kernel driver are loaded, > we'll scan the device twice? > Will it be probed 2 times? > > No, it won't probe twice. I suppose that each PCI device will only be bound to either the VFIO driver or a kernel driver. The drv_flags of the xsc_pmd PCI driver will not preset with RTE_PCI_DRV_NEED_MAPPING. Therefore, in the rte_pci_probe_one_driver function, rte_pci_map_device() will not be called. After entering the probe phase of the xsc PMD PCI driver, rte_pci_map_device() will be called in xsc_dev_ops->init() based on whether it is a VFIO driver.
Thank you. -- Best regards, Renyong Wan
