Re: [PATCH v3 03/13] x86/hvm: Scale host TSC when setting/getting guest TSC

[Haozhong Zhang <haozhong.zhang@intel.com>]

On 01/08/16 02:15, Jan Beulich wrote:
> >>> On 31.12.15 at 04:03, <haozhong.zhang@intel.com> wrote:
> > --- a/xen/arch/x86/hvm/svm/svm.c
> > +++ b/xen/arch/x86/hvm/svm/svm.c
> > @@ -804,6 +804,16 @@ static uint64_t scale_tsc(uint64_t host_tsc, uint64_t ratio)
> >      return scaled_host_tsc;
> >  }
> >  
> > +static uint64_t svm_scale_tsc(struct vcpu *v, uint64_t tsc)
> > +{
> > +    struct domain *d = v->domain;
> > +
> > +    if ( !cpu_has_tsc_ratio || d->arch.vtsc )
> 
> The left side of this check is redundant with those at both call sites.
> It should either be removed altogether, or converted to an ASSERT().
> Perhaps the right side should move into the callers too (as being
> vendor independent), or if not at least the pointless local variable
> should be eliminated.
>

Yes, I'll remove the left check and move the right check to callers. 
 
> Further I suppose this new hook really could/should have its
> first argument const qualified (the hook isn't supposed to fiddle
> with the vCPU).
>

I'll add 'const'.

Haozhong