> From: Liu, Yi L <yi.l.liu@xxxxxxxxx> > Sent: Tuesday, February 28, 2023 11:03 AM > > From: Jason Gunthorpe <jgg@xxxxxxxxxx> > > Sent: Tuesday, February 28, 2023 3:21 AM > > > > On Mon, Feb 27, 2023 at 03:11:16AM -0800, Yi Liu wrote: > > > Existing VFIO provides group-centric user APIs for userspace. > > > Userspace opens the /dev/vfio/$group_id first before getting device > > > fd and hence getting access to device. This is not the desired model > > > for iommufd. Per the conclusion of community discussion[1], iommufd > > > provides device- > > centric > > > kAPIs and requires its consumer (like VFIO) to be device-centric > > > user APIs. Such user APIs are used to associate device with iommufd > > > and also the I/O address spaces managed by the iommufd. > > > > > > This series first introduces a per device file structure to be > > > prepared for further enhancement and refactors the kvm-vfio code to > > > be prepared for accepting device file from userspace. Then refactors > > > the vfio to be able to handle iommufd binding. This refactor > > > includes the mechanism of blocking device access before iommufd > > > bind, making the device_open > > exclusive. > > > between the group path and the cdev path. Eventually, adds the cdev > > support > > > for vfio device, and makes group infrastructure optional as it is > > > not needed when vfio device cdev is compiled. > > > > > > This is also a prerequisite for iommu nesting for vfio device[2]. > > > > > > The complete code can be found in below branch, simple test done > > > with > > the > > > legacy group path and the cdev path. Draft QEMU branch can be found > > at[3] > > > > > > https://github.com/yiliu1765/iommufd/tree/vfio_device_cdev_v5 > > > (config CONFIG_IOMMUFD=y CONFIG_VFIO_DEVICE_CDEV=y) > > > > > > base-commit: 63777bd2daa3625da6eada88bd9081f047664dad > > > > This needs to be rebased onto a clean v6.3-rc1 when it comes out > > Yes, I'll send rebase and send one more version when v6.3-rc1 comes. Here > just try to be near to the vfio code in Alex's next branch. > > Regards, > Yi Liu Verified this series by "Intel GVT-g GPU device mediated passthrough" and "Intel GVT-d GPU device direct passthrough" technologies. Both passed VFIO legacy mode / compat mode / cdev mode, including negative tests. Tested-by: Terrence Xu <terrence.xu@xxxxxxxxx>
