Re: [Qemu-arm] [Qemu-devel] [PATCH V4 1/2] arm64: Add an option to turn on/off vPMU support

[Andrew Jones]

On Wed, Sep 21, 2016 at 08:35:41AM -0500, Wei Huang wrote:
> On 09/21/2016 02:53 AM, Andrew Jones wrote:
> > On Tue, Sep 20, 2016 at 10:33:53PM -0400, Wei Huang wrote:
[snip]
> >> +    if (cpu->has_pmu == ON_OFF_AUTO_ON && !kvm_enabled()) {
> >> +        cpu->has_pmu = ON_OFF_AUTO_OFF;
> >> +        if (!pmu_warned && !qtest_enabled()) {
> > 
> > Why do we need this qtest_enabled thing?
> 
> Without this, "make check" will print out the warning message (using a
> qtest machine type). This seems to be a common practice across QEMU code.

I see. Too bad it's so ugly. Maybe we need a new error_report that
hides that ugliness, i.e. an error_report that only reports when
!qtest_enabled(). CC'ing Markus to get his opinion, but I'm off topic
now and wouldn't expect anything like that to be worked out before
accepting this patch.

> 
> > 
> >> +            error_report("warning: pmu can't be enabled without KVM 
> >> acceleration");
> >> +            pmu_warned = true;
> >> +        }
> >> +    }
> >> +    if (cpu->has_pmu == ON_OFF_AUTO_OFF) {
> >> +        unset_feature(env, ARM_FEATURE_PMU);
> >> +    }
> >> +
[snip]

Thanks,
drew