[libvirt] [PATCH 2/4] cpu: Better support for ppc64 compatibility modes

[Andrea Bolognani]

On Fri, 2015-08-21 at 14:27 -0700, Jiri Denemark wrote:

> > +static virCPUCompareResult
> > +ppc64CheckCompatibilityMode(const char *host_model,
> > +                            const char *compat_mode)
> > +{
> > +    int host;
> > +    int compat;
> > +    char *tmp;
> > +    virCPUCompareResult ret = VIR_CPU_COMPARE_IDENTICAL;
> 
> Shouldn't ret be initialized to VIR_CPU_COMPARE_ERROR so that we
> don't
> report everything is OK on errors?

Initializing it to VIR_CPU_COMPARE_IDENTICAL allows us to
just jump to the exit point if a compatibility mode is not
used (see check right below).

That could be replaced with an explicit return if you
think that would make the code easier to understand.

> > +
> > +    if (!compat_mode)
> > +        goto out;
[...]
> > +    ret = VIR_CPU_COMPARE_INCOMPATIBLE;
> > +
> > +    /* Version check */
> > +    if (compat > host)
> > +        goto out;
> > +
> > +    ret = VIR_CPU_COMPARE_IDENTICAL;
> 
>     if (compat > host)
>         ret = VIR_CPU_COMPARE_INCOMPATIBLE;
>     else
>         ret = VIR_CPU_COMPARE_IDENTICAL;
> 
> would be a bit more obvious I think.

Both work for me, so why not :)

> In the long term, I think we should store compatibility modes within
> cpu_map.xml, but ACK to this with the small issues addressed.

Sure, that will come later on.

Cheers.

-- 
Andrea Bolognani
Software Engineer - Virtualization Team