On Tue, Jun 03, 2025 at 09:08:10AM -0300, Jason Gunthorpe wrote: > On Tue, Jun 03, 2025 at 11:47:33AM +0800, Xu Yilun wrote: > > > VFIO doesn't have enough information, but VFIO needs to know about > > bound state. So comes the suggestion [1] that the VFIO uAPI, then VFIO > > reach into iommufd for real bind. > > > > And my implementation [2] is: > > > > ioctl(vfio_cdev_fd, VFIO_DEVICE_TSM_BIND) > > -> vfio_iommufd_tsm_bind() > > -> iommufd_device_tsm_bind() > > -> iommufd_vdevice_tsm_bind() > > -> pci_tsm_bind() > > This doesn't work, logically you are binding the vdevice, not the > idevice, the uapi should provide the vdevice id, which VFIO doesn't > have. Yes. Sorry I just too lazy to provide the full API format. The original suggestion [1] is to provide vdevice_id in VFIO uAPI. [1] https://lore.kernel.org/all/20250515175658.GR382960@xxxxxxxxxx/ And here is a piece of the implementation in [2]: +struct vfio_pci_tsm_bind { + __u32 argsz; + __u32 flags; + __u32 vdevice_id; + __u32 pad; +}; + +#define VFIO_DEVICE_TSM_BIND _IO(VFIO_TYPE, VFIO_BASE + 22) [2] https://lore.kernel.org/all/20250529053513.1592088-20-yilun.xu@xxxxxxxxxxxxxxx/ > > If you really need vfio involvement then you need callbacks, I think. Only callback is not enough, there are cases that VFIO wants actively invalidate MMIO, e.g. VFIO_DEVICE_RESET. In that case, VFIO needs dynamic unbind then invalidate MMIO. Thanks, Yilun > > Jason
