On Wed, Sep 06, 2023 at 01:09:26PM -0600, Alex Williamson wrote: > 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,
Yeah, I was thinking 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, Indeed, I got confused because this removed the TODO - that could reasonably be pushed to the next patch and include a bit more detail in the commit message Jason
