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?
Cheers,
Matt
>
> On Tue, 2011-12-06 at 14:39 +1100, Matt Evans wrote:
>> kvm_cpu__run() currently die()s if KVM_RUN returns non-zero. Some architectures
>> may return positive values in non-error cases, whereas real errors are always
>> negative return values. Check for those instead.
>>
>> Signed-off-by: Matt Evans <matt@xxxxxxxxxx>
>> ---
>> tools/kvm/kvm-cpu.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/tools/kvm/kvm-cpu.c b/tools/kvm/kvm-cpu.c
>> index 9bc0796..884a89f 100644
>> --- a/tools/kvm/kvm-cpu.c
>> +++ b/tools/kvm/kvm-cpu.c
>> @@ -30,7 +30,7 @@ void kvm_cpu__run(struct kvm_cpu *vcpu)
>> int err;
>>
>> err = ioctl(vcpu->vcpu_fd, KVM_RUN, 0);
>> - if (err && (errno != EINTR && errno != EAGAIN))
>> + if (err < 0 && (errno != EINTR && errno != EAGAIN))
>> die_perror("KVM_RUN failed");
>> }
>>
>> --
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