Re: [PATCH v2 6/6] libxl: add support for parsing MSR features

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Jul 13, 2023 at 11:39:53AM +0100, Anthony PERARD wrote:
> On Tue, Jul 11, 2023 at 11:22:30AM +0200, Roger Pau Monne wrote:
> > diff --git a/tools/libs/light/libxl_cpuid.c b/tools/libs/light/libxl_cpuid.c
> > index b1c4f8f2f45b..86a08f29a19c 100644
> > --- a/tools/libs/light/libxl_cpuid.c
> > +++ b/tools/libs/light/libxl_cpuid.c
> > @@ -158,6 +158,57 @@ static int cpuid_add(libxl_cpuid_policy_list *policy,
> >      return 0;
> >  }
> >  
> > +static struct xc_msr *msr_find_match(libxl_cpuid_policy_list *pl, uint32_t 
> > index)
> > +{
> > +    unsigned int i = 0;
> > +    libxl_cpuid_policy_list policy = *pl;
> > +
> > +    if (policy == NULL)
> > +        policy = *pl = calloc(1, sizeof(*policy));
> > +
> > +    if (policy->msr != NULL)
> > +        for (i = 0; policy->msr[i].index != XC_MSR_INPUT_UNUSED; i++)
> 
> Could you add { } for this two blocks? One line after a if() without { }
> is ok, but not more.

Sure.

> > +            if (policy->msr[i].index == index)
> > +                return &policy->msr[i];
> > +
> > +    policy->msr = realloc(policy->msr, sizeof(struct xc_msr) * (i + 2));
> > +    policy->msr[i].index = index;
> > +    memset(policy->msr[i].policy, 'x', ARRAY_SIZE(policy->msr[0].policy) - 
> > 1);
> 
> Is this "array_size() - 1" correct? The -1 need to go, right?
> 
> > +    policy->msr[i].policy[ARRAY_SIZE(policy->msr[0].policy) - 1] = '\0';
> 
> Is it for convenience? Maybe for easier debugging (printf)? Also, I
> guess having a NUL at the end mean the -1 on the previous statement kind
> of useful.

Yes, it's also to match the format of the policy string used by
xc_xend_cpuid, which also has a terminating zero.

Are you OK with this?

Thanks, Roger.