Messages in this thread | | | Date | Fri, 6 May 2022 17:56:25 +0200 | Subject | Re: [PATCH v6 16/21] vfio-pci/zdev: add open/close device hooks | From | Christian Borntraeger <> |
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Am 27.04.22 um 17:39 schrieb Jason Gunthorpe: > 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@linux.ibm.com/ >> >> 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
I agree with Jason here.
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