Re: [Xen-devel] [PATCH v3 05/15] x86: implement get hw info flow for MBA

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

On 17-09-19 10:08:22, Roger Pau Monn� wrote:
> On Tue, Sep 05, 2017 at 05:32:27PM +0800, Yi Sun wrote:
> > diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
> > index 10776d2..0486d2d 100644
> > --- a/xen/arch/x86/psr.c
> > +++ b/xen/arch/x86/psr.c
> > @@ -491,7 +495,18 @@ static const struct feat_props l2_cat_props = {
> >  static bool mba_get_feat_info(const struct feat_node *feat,
> >                                uint32_t data[], unsigned int array_len)
> >  {
> > -    return false;
> > +    if ( array_len != PSR_INFO_ARRAY_SIZE )
> > +        return false;
> > +
> > +    data[PSR_INFO_IDX_COS_MAX] = feat->cos_max;
> > +    data[PSR_INFO_IDX_MBA_THRTL_MAX] = feat->mba.thrtl_max;
> > +
> > +    if ( feat->mba.linear )
> > +        data[PSR_INFO_IDX_MBA_FLAG] |= XEN_SYSCTL_PSR_ALLOC_MBA_LINEAR;
> > +    else
> > +        data[PSR_INFO_IDX_MBA_FLAG] &= ~XEN_SYSCTL_PSR_ALLOC_MBA_LINEAR;
> 
> This branch of the if shouldn't be needed...
> 
> > +
> > +    return true;
> >  }
> >  
> >  static void mba_write_msr(unsigned int cos, uint32_t val,
> > diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
> > index 1d3dbd0..4634cad 100644
> > --- a/xen/arch/x86/sysctl.c
> > +++ b/xen/arch/x86/sysctl.c
> > @@ -214,6 +214,25 @@ long arch_do_sysctl(
> >              break;
> >          }
> >  
> > +        case XEN_SYSCTL_PSR_ALLOC_get_mba_info:
> > +        {
> > +            ret = psr_get_info(sysctl->u.psr_alloc.target,
> > +                               PSR_TYPE_MBA_THRTL, data, ARRAY_SIZE(data));
> 
> ... because data should be initialized, ie:
> 
> uint32_t data[PSR_INFO_ARRAY_SIZE] = { 0 };
> 
> So that we don't leak stack data in the sysctl.
> 
Ok, thanks!

> Thanks, Roger.

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