On Wed, Apr 27, 2022 at 11:26:40AM -0400, Matthew Rosato wrote: > > > zPCI devices (zpci_dev) exist regardless of whether kvm is configured or > > > not, and you can e.g. bind the associated PCI device to vfio-pci when KVM is > > > not configured (or module not loaded) and get the existing vfio-pci-zdev > > > extensions for that device (extra VFIO_DEVICE_INFO response data). Making a > > > direct dependency on KVM would remove that; this was discussed in a prior > > > version because this extra info is not used today outside of a KVM usecase > > > are not specific to kvm that need vfio-pci-zdev). > > > > I'm a bit confused, what is the drawback of just having a direct > > symbol dependency here? It means vfio loads a little extra kernel > > module code, but is that really a big worry given almost all vfio > > users on s390 will be using it with kvm? > > It's about trying to avoid loading unnecessary code (or at least giving a > way to turn it off). > > Previously I did something like.... > > https://lore.kernel.org/kvm/20220204211536.321475-15-mjrosato@xxxxxxxxxxxxx/ > > And could do so again; as discussed in the thread there, I can use e.g. > CONFIG_VFIO_PCI_ZDEV_KVM and make vfio-pci-zdev depend on KVM in this > series. You only get the vfio-pci-zdev extensions when you configure KVM. That make sense to me, I'd rather see that then the symbol_get/put here Thanks, Jason
