Re: [Xen-devel] [PATCH v4 1/2] x86/hvm: Always do SMAP check when updating runstate_guest(v)

["Wu, Feng" <feng.wu@xxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: Wednesday, July 30, 2014 4:15 PM
> To: Wu, Feng
> Cc: linux@xxxxxxxxxxxxxx; xen-devel@xxxxxxxxxxxxx; keir@xxxxxxx;
> tim@xxxxxxx
> Subject: Re: [PATCH v4 1/2] x86/hvm: Always do SMAP check when updating
> runstate_guest(v)
> 
> >>> On 30.07.14 at 03:35, <feng.wu@xxxxxxxxx> wrote:
> > @@ -1349,22 +1357,33 @@ static void paravirt_ctxt_switch_to(struct vcpu
> *v)
> >  }
> >
> >  /* Update per-VCPU guest runstate shared memory area (if registered). */
> > -bool_t update_runstate_area(const struct vcpu *v)
> > +bool_t update_runstate_area(struct vcpu *v)
> >  {
> > +    bool_t rc;
> > +    smap_check_policy_t smap_policy;
> > +
> >      if ( guest_handle_is_null(runstate_guest(v)) )
> >          return 1;
> >
> > +    smap_policy = smap_policy_change(v, SMAP_CHECK_ENABLED);
> > +
> >      if ( has_32bit_shinfo(v->domain) )
> >      {
> >          struct compat_vcpu_runstate_info info;
> >
> >          XLAT_vcpu_runstate_info(&info, &v->runstate);
> >          __copy_to_guest(v->runstate_guest.compat, &info, 1);
> > -        return 1;
> > +        smap_policy_change(v, smap_policy);
> > +        rc = 1;
> > +    }
> > +    else
> > +    {
> > +        rc = __copy_to_guest(runstate_guest(v), &v->runstate, 1) !=
> > +             sizeof(v->runstate);
> > +        smap_policy_change(v, smap_policy);
> >      }
> 
> The common smap_policy_change(v, smap_policy) should have been
> pulled out of the if and else parts. I'll see to remember doing this when
> committing (assuming that not other issue with the patch gets spotted
> by someone else).
> 
> Jan

Thanks a lot. I forgot that one.

Thanks,
Feng


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