On 25.09.19 10:26, Paolo Bonzini wrote: > On 25/09/19 10:10, Sergio Lopez wrote: >> That would be great. I'm also looking forward for virtio-mem (and an >> hypothetical virtio-cpu) to eventually gain hotplug capabilities in >> microvm. > > I disagree with this. virtio is not a silver bullet (and in fact > perhaps it's just me but I've never understood the advantages of > virtio-mem over anything else). Sorry, I had to lol about "virtio-mem over anything else". No, not starting a discussion. > > If you want to add hotplug to microvm, you can reuse the existing code > for CPU and memory hotplug controllers, and write drivers for them in > Linux's drivers/platform. The drivers would basically do what the ACPI > AML tells the interpreter to do. > > There is no reason to add the complexity of virtio to something as > low-level and deadlock-prone as CPU hotplug. I do agree in respect of CPU hotplug complexity (especially accross architectures), but thinking "outside of the wonderful x86 world", other architectures impose limitations (e.g., no cpu unplug on s390x - at least for now) that make something like this very interesting. But yeah, I already expressed somewhere else my feelings about CPU hotplug. I consider virtio the silver bullet whenever we want a mature paravirtualized interface across architectures. And you can tell that I'm not the only one by the huge amount of virtio device people are crafting right now. -- Thanks, David / dhildenb
