* Avi Kivity <avi@xxxxxxxxxx> wrote: > > That is not what i said. I said they are closely related, and where > > technologies are closely related, project proximity turns into project > > unification at a certain stage. > > I really don't see how. So what if both qemu and kvm implement an i8254? > They can't share any code since the internal APIs are so different. [...] I wouldnt jump to assumptions there. perf shares some facilities with the kernel on the source code level - they can be built both in the kernel and in user-space. But my main thought wasnt even to actually share the implementation - but to actually synchronize when a piece of device emulation moves into the kernel. It is arguably bad for performance in most cases when Qemu handles a given device - so all the common devices should be kernel accelerated. The version and testing matrix would be simplified significantly as well: as kernel and qemu goes hand in hand, they are always on the same version. > [...] Even worse for the x86 emulator as qemu and kvm are fundamentally > different. So is it your argument that the difference and the duplication in x86 instruction emulation is a good thing? You said it some time ago that the kvm x86 emulator was very messy and you wish it was cleaner. While qemu's is indeed rather different (it's partly a translator/JIT), i'm sure the decoder logic could be shared - and qemu has a slow-path full-emulation fallback in any case, which is similar to what in-kernel emulator does (IIRC ...). That might have changed meanwhile. Ingo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
