Re: [Xen-devel] [PATCH v2 4/6] xsm: flask: change the dummy xsm policy and flask hook for map_gmfn_foregin

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 27.08.17 at 10:36, <blackskygg@xxxxxxxxx> wrote:
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -1284,7 +1284,7 @@ int xenmem_add_to_physmap_one(
>              return -EINVAL;
>          }
>  
> -        rc = xsm_map_gmfn_foreign(XSM_TARGET, d, od);
> +        rc = xsm_map_gmfn_foreign(XSM_TARGET, current->domain, d, od);
>          if ( rc )
>          {
>              rcu_unlock_domain(od);
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -2545,7 +2545,7 @@ int p2m_add_foreign(struct domain *tdom, unsigned long 
> fgfn,
>      if ( tdom == fdom )
>          goto out;
>  
> -    rc = xsm_map_gmfn_foreign(XSM_TARGET, tdom, fdom);
> +    rc = xsm_map_gmfn_foreign(XSM_TARGET, current->domain, tdom, fdom);

I continue to dislike the added arguments here, as being pointless
to pass. I'm not the maintainer of either of the modified files, so I
won't (and can't) veto the change though.

> --- a/xen/include/xsm/dummy.h
> +++ b/xen/include/xsm/dummy.h
> @@ -525,10 +525,14 @@ static XSM_INLINE int 
> xsm_remove_from_physmap(XSM_DEFAULT_ARG struct domain *d1,
>      return xsm_default_action(action, d1, d2);
>  }
>  
> -static XSM_INLINE int xsm_map_gmfn_foreign(XSM_DEFAULT_ARG struct domain *d, 
> struct domain *t)
> +static XSM_INLINE int xsm_map_gmfn_foreign(XSM_DEFAULT_ARG struct domain *cd,
> +                                           struct domain *d, struct domain 
> *t)
>  {
> +    int rc;
>      XSM_ASSERT_ACTION(XSM_TARGET);

Missing blank line between declaration and statements.

> -    return xsm_default_action(action, d, t);
> +    rc = xsm_default_action(action, cd, d);
> +    if (rc) return rc;

Coding style. In any event, as suggested before the whole thing is
easier to write as

> +    return xsm_default_action(action, cd, t);

    return xsm_default_action(action, cd, d) ?: xsm_default_action(action, cd, 
t);

anyway imo (suitably split across lines if needed, of course).

> --- a/xen/xsm/flask/hooks.c
> +++ b/xen/xsm/flask/hooks.c
> @@ -1165,9 +1165,15 @@ static int flask_remove_from_physmap(struct domain 
> *d1, struct domain *d2)
>      return domain_has_perm(d1, d2, SECCLASS_MMU, MMU__PHYSMAP);
>  }
>  
> -static int flask_map_gmfn_foreign(struct domain *d, struct domain *t)
> +static int flask_map_gmfn_foreign(struct domain *cd,
> +                                  struct domain *d, struct domain *t)
>  {
> -    return domain_has_perm(d, t, SECCLASS_MMU, MMU__MAP_READ | 
> MMU__MAP_WRITE);
> +    int rc;
> +    rc = domain_has_perm(cd, d, SECCLASS_MMU, MMU__MAP_READ | 
> MMU__MAP_WRITE);
> +    if (rc) return rc;
> +    rc = domain_has_perm(cd, t, SECCLASS_MMU, MMU__MAP_READ | 
> MMU__MAP_WRITE);
> +    if (rc) return rc;
> +    return domain_has_perm(d, t, SECCLASS_MMU, MMU__SHARE_MEM);
>  }

At least the style problems mentioned above apply here too.

Jan


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