Messages in this thread | | | Date | Tue, 04 Aug 2020 18:16:30 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH v1 3/3] kernel/configs: don't include PCI_QUIRKS in KVM guest configs |
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On 2020-08-04 16:40, Alex Bennée wrote: > Marc Zyngier <maz@kernel.org> writes: > >> On 2020-08-04 15:44, Alex Bennée wrote: >>> Marc Zyngier <maz@kernel.org> writes: >>> >>>> On 2020-08-04 13:44, Alex Bennée wrote: >>>>> The VIRTIO_PCI support is an idealised PCI bus, we don't need a >>>>> bunch >>>>> of bloat for real world hardware for a VirtIO guest. >>>> >>>> Who says this guest will only have virtio devices? >>> >>> This is true - although what is the point of kvm_guest.config? We >>> certainly turn on a whole bunch of virt optimised pathways with >>> PARAVIRT >>> and HYPERVISOR_GUEST along with the rest of VirtIO. >> >> Most of which actually qualifies as bloat itself as far as KVM/arm64 >> is concerned... > > So here is the question - does the kernel care about having a blessed > config for a minimal viable guest? They are certainly used in the cloud > but I understand the kernel is trying to get away from having a zoo of > configs. What is the actual point of kvm_guest.config? Just an easy > enabling for developers?
The cloud vendor I know certainly doesn't provide a "dumbed down" kernel configuration. What they run is either a distro kernel or something that fits their environment (which does include HW PCI devices, and hardly any virtio device).
My take is that this kvm-special config isn't that useful in the real world, and I don't believe there is such thing as a "minimal viable guest" config, certainly not across architectures and VMMs. Hopefully it fits someone's development workflow, but that's probably it.
M. -- Jazz is not dead. It just smells funny...
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