Re: [Qemu-devel] [PATCH] kvm: Set default accelerator to "kvm" if the host supports it

[Peter Maydell]

On 5 October 2012 03:24, Alexander Graf <address@hidden> wrote:
> On 05.10.2012, at 04:17, Anthony Liguori wrote:
>> Alexander Graf <address@hidden> writes:
>>> We get similar problems on PPC. Take the following example:
>>>
>>>  $ qemu-system-ppc -M mpc8544ds -kernel uImage -nographic
>>
>> But do you really expect people to do this?  I have to believe that
>> people running on PPC hardware and running qemu-system-ppc most likely
>> want to do KVM...
>
> Sure. But we wouldn't be able to even tell them what went wrong,
> as we don't have a negotiation mechanism right now that could tell
> user space "hey, the CPU you selected is unknown to me".

On ARM we will at least be able to say what happened, because
our kvm_arch_init_vcpu() will fail (when we try the ioctl to
tell the kernel "be this kind of CPU") and we can print a
message there. However QEMU as a whole doesn't have any way of
falling back to TCG at that point so it just bails out.

-- PMM