Re: Merging kvm-apic into qemu-kvm

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-01-26 16:25, Jan Kiszka wrote:
> On 2012-01-26 16:15, Avi Kivity wrote:
>> The changes to kvm-apic are so drastic, that merging them into qemu-kvm
>> in the normal way won't work.  I can consider just dropping the existing
>> implementation and switching to the new one, but the comment at the end
>>
>>     Make the basic in-kernel irqchip support selectable via
>>     -machine ...,kernel_irqchip=on. Leave it off by default until it can
>>     fully replace user space models.
>>
>> suggests that things are still missing.
>>
>> Jan, what's still missing?
> 
> - in-kernel PIT (patches done, waiting for some upstream bits to be
>   merged first)
> - TPR acceleration via VAPIC (WIP)
> - MSI support
> 
> The latter is the big chunk. It requires quite some
> refactoring/enhancement of the MSI layer. I posted the first version
> last year. We need to agree on the design, then probably switch qemu-kvm
> over while pushing generic bits upstream. And then we can extend the
> upstream in-kernel *PIC using that new interfaces. Once upstream works
> with MSI, we can switch qemu-kvm over, leaving basically only
> device-assignment as the last missing bit.
> 
>>  Any idea on how to proceed?
> 
> I had a qemu-kvm branch here that disables the upstream in-kernel *PIC
> in favor of its current version. I still need to refresh that work (was
> based on an earlier revision), but it was not that horrible. Let me check...

It's online, see
http://git.kiszka.org/?p=qemu-kvm.git;a=shortlog;h=refs/heads/kvm-irqchip-merge

I merged the upstream patches one by one, resolving the mechanical and
logical conflicts in each step. Was done for that backend/frontend
concept, but the adjustments should basically be the same now. Want me
to prepare a branch or will you do this?

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux