Re: [Xen-devel] [PATCH v3 06/15] x86: implement get value interface for MBA

[Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>]

On 17-09-19 10:15:42, Roger Pau Monn� wrote:
> On Tue, Sep 05, 2017 at 05:32:28PM +0800, Yi Sun wrote:
> > diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
> > index 696eff2..7902af7 100644
> > --- a/xen/arch/x86/domctl.c
> > +++ b/xen/arch/x86/domctl.c
> > @@ -1496,6 +1496,13 @@ long arch_do_domctl(
> >              copyback = true;
> >              break;
> >  
> > +        case XEN_DOMCTL_PSR_ALLOC_GET_MBA_THRTL:
> > +            ret = psr_get_val(d, domctl->u.psr_alloc.target,
> > +                              &val32, PSR_TYPE_MBA_THRTL);
> > +            domctl->u.psr_alloc.data = val32;
> 
> Hm, why does psr_get_val take a uint32_t * instead of a uint64_t *? So
> that you can directly pass &domctl->u.psr_alloc.data.
> 
> Or the other way around, why is domctl->u.psr_alloc.data a uint64_t
> instead of a uint32_t?
> 
There is a historical reason. The COS MSR is 64bit. So, the original codes
in L3 CAT (submitted years ago) used uint64_t.

But during L2 CAT review, per Jan's comment, the uint64_t is not necessary
in psr.c. So, we convert it to uint32_t in psr.c and make the codes you see
here.

> Thanks, Roger.

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