On Fri, May 16, 2025 at 12:04:04AM +0800, Xu Yilun wrote: > > arches this was mostly invisible to the hypervisor? > > Attest & Accept can be invisible to hypervisor, or host just help pass > data blobs between guest, firmware & device. > > Bind cannot be host agnostic, host should be aware not to touch device > after Bind.
I'm not sure this is fully true, this could be a Intel thing. When the vPCI is created the host can already know it shouldn't touch the PCI device anymore and the secure world would enforce that when it gets a bind command. The fact it hasn't been locked out immediately at vPCI creation time is sort of a detail that doesn't matter, IMHO. > > It might be reasonable to have VFIO reach into iommufd to do that on > > an already existing iommufd VDEVICE object. A little weird, but we > > could probably make that work. > > Mm, Are you proposing an uAPI in VFIO, and a kAPI from VFIO -> IOMMUFD like: > > ioctl(vfio_fd, VFIO_DEVICE_ATTACH_VDEV, vdev_id) > -> iommufd_device_attach_vdev() > -> tsm_tdi_bind() Not ATTACH, you wanted BIND. You could have a VFIO_DEVICE_BIND(iommufd vdevice id) > > sees VFIO remove the S-EPT and release the KVM, then have iommufd > > destroy the VDEVICE object. > > Regarding VM destroy, TDX Connect has more enforcement, VM could only be > destroyed after all assigned CC vPCI devices are destroyed. And KVM destroys the VM? > Nowadays, VFIO already holds KVM reference, so we need > > close(vfio_fd) > -> iommufd_device_detach_vdev() This doesn't happen though, it destroys the normal device (idev) which the vdevice is stacked on top of. You'd have to make normal device destruction trigger vdevice destruction > -> tsm_tdi_unbind() > -> tdi stop > -> callback to VFIO, dmabuf_move_notify(revoke) > -> KVM unmap MMIO > -> tdi metadata remove This omits the viommu. It won't get destroyed until the iommufd closes, so iommufd will be holding the kvm and it will do the final put. Jason
