On Wed, 6 Sep 2023 15:10:39 -0300 Jason Gunthorpe <j...@nvidia.com> wrote:
> On Wed, Aug 30, 2023 at 06:37:53PM +0800, Zhenzhong Duan wrote: > > Note the /dev/iommu device may have been pre-opened by a > > management tool such as libvirt. This mode is no more considered > > for the legacy backend. So let's remove the "TODO" comment. > > Can you show an example of that syntax too? Unless you're just looking for something in the commit log, patch 16/ added the following to the qemu help output: +#ifdef CONFIG_IOMMUFD + ``-object iommufd,id=id[,fd=fd]`` + Creates an iommufd backend which allows control of DMA mapping + through the /dev/iommu device. + + The ``id`` parameter is a unique ID which frontends (such as + vfio-pci of vdpa) will use to connect withe the iommufd backend. + + The ``fd`` parameter is an optional pre-opened file descriptor + resulting from /dev/iommu opening. Usually the iommufd is shared + accross all subsystems, bringing the benefit of centralized + reference counting. +#endif > Also, the vfio device should be openable externally as well Appears to be added in the very next patch in the series. Thanks, Alex
