Re: [PATCH 08/28] kvm tools: Fix KVM_RUN exit code check

Alexander Graf
2011-12-07T15:01:06Z

On 07.12.2011, at 15:12, Avi Kivity <avi@redhat.com> wrote:

> On 12/07/2011 08:44 AM, Alexander Graf wrote:
>> On 07.12.2011, at 01:32, Matt Evans <matt@ozlabs.org> wrote:
>>
>>> On 06/12/11 19:22, Sasha Levin wrote:
>>>> If KVM_RUN can actually return anything besides 0 or -1 it may be also
>>>> worthwhile to update Documentation/virtual/kvm/api.txt .
>>>>
>>>> What are the cases where it happens?
>>>
>>> Well, on PPC the internal kvmppc_run_vcpu() returns either RESUME_GUEST (which
>>> stays in-kernel and drops back to the guest) or RESUME_HOST, which is propagated
>>> back out to userland as the return value of ioctl(KVM_RUN). So, anything
>>> kvmtool sees is either <0 for error or RESUME_HOST, i.e. 2.
>>>
>>> Alex, do you think the PPC KVM code should be forced to 0 on success, or is
>>> there any value to the expanded the return codes (and updating api.txt) for
>>> varying kinds of positive success?
>>
>> I don't think it's worth the potential ABI breakage to change the current behavior :). Even if we did change it, you would still have to touch kvm tool to work with older kernels.
>
> Well it deviates from api.txt, so please fix one or the other.

Hrm - let me check all users. Maybe we can change the return argument. Will do when I'm back on a keyboard ;).

Alex

>