> From: Alex Williamson <alex.williamson@xxxxxxxxxx> > Sent: Wednesday, March 22, 2023 5:01 AM > > On Tue, 21 Mar 2023 17:50:08 -0300 > Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > > > > > Though it would be nice if qemu didn't need two implementations so Yi > > I'd rather see a new info in this series as well and qemu can just > > consistently use dev_id and never bdf in iommufd mode. > > We also need to consider how libvirt determines if QEMU has the kernel > support it needs to pass file descriptors. It'd be a lot cleaner if > this aligned with the introduction of vfio cdevs. > Libvirt can check whether the kernel creates cdev for a given device via sysfs. but I'm not sure how Libvirt determines whether QEMU supports a feature that it wants to use. But sounds this is a general handshake problem as Libvirt needs to support many versions of QEMU then there must be a way for such negotiation?
