On Tue, Apr 15, 2025 at 10:25:42AM +0100, Jonathan Cameron wrote: > On Tue, 15 Apr 2025 09:11:03 +0100 > Shameer Kolothum <shameerali.kolothum.th...@huawei.com> wrote: > > > Allow cold-plug of smmuv3 device to virt If the machine wide smmuv3 > > or a virtio-iommu is not specified. > > > > Also restrict the usage if virt <= 9.2. This will prevent accidently > > creating a SMMUv3 device on machines prior to 9.2 and cause failure > > on migrating to machines with same version but has a legacy smmuv3 > > device. > > Hi, > > As we discussed internally I'm not convinced we need to prevent this > particular > way for a user to shoot themselves in the foot. > > To be a problem they have to specifically request an old machine + the > device that didn't exist for that machine, then migrate to a real old > version of QEMU. Agreed it is possible but I'm not sure we need to > prevent that particular crazy.
Agreed, there are a million ways to screw up using old machine types with new features, so there's no compelling need to single out smmu for special protection in this respect. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
