Re: [PATCH v4 09/11] silo: remove circular xsm hook call

From: Andrew Cooper <andrew.cooper3@citrix.com>
To: "Daniel P. Smith" <dpsmith@apertussolutions.com>,
	<xen-devel@lists.xenproject.org>
Cc: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Subject: Re: [PATCH v4 09/11] silo: remove circular xsm hook call
Date: Mon, 6 Sep 2021 19:55:07 +0100	[thread overview]
Message-ID: <d415ab82-ca83-98e8-0b07-0e093a1fa7e1@citrix.com> (raw)
In-Reply-To: <20210903190629.11917-10-dpsmith@apertussolutions.com>

On 03/09/2021 20:06, Daniel P. Smith wrote:
> SILO implements a few XSM hooks to extended the decision logic beyond
> what is defined in the dummy/default policy. For each of the hooks, it
> falls back to the dummy/default policy. The fall back is done a slight
> round-about way.

"done in a slightly" ?

>  This commit makes the direct call to the default policy's
> logic, xsm_default_action().
>
> Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
> ---
>  xen/xsm/silo.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/xen/xsm/silo.c b/xen/xsm/silo.c
> index 6db793f35c..56a330a831 100644
> --- a/xen/xsm/silo.c
> +++ b/xen/xsm/silo.c
> @@ -17,6 +17,7 @@
>   * You should have received a copy of the GNU General Public License along with
>   * this program; If not, see <http://www.gnu.org/licenses/>.
>   */
> +#include <xsm/xsm-core.h>
>  #include <xsm/dummy.h>
>  
>  /*
> @@ -43,7 +44,7 @@ static int silo_evtchn_unbound(struct domain *d1, struct evtchn *chn,
>      else
>      {
>          if ( silo_mode_dom_check(d1, d2) )
> -            rc = xsm_evtchn_unbound(d1, chn, id2);
> +            rc = xsm_default_action(XSM_TARGET, current->domain, d1);
>          rcu_unlock_domain(d2);
>      }
>  
> @@ -54,7 +55,7 @@ static int silo_evtchn_interdomain(struct domain *d1, struct evtchn *chan1,
>                                     struct domain *d2, struct evtchn *chan2)
>  {
>      if ( silo_mode_dom_check(d1, d2) )
> -        return xsm_evtchn_interdomain(d1, chan1, d2, chan2);
> +        return xsm_default_action(XSM_HOOK, d1, d2);
>      return -EPERM;
>  }
>  
> @@ -62,21 +63,21 @@ static int silo_grant_mapref(struct domain *d1, struct domain *d2,
>                               uint32_t flags)
>  {
>      if ( silo_mode_dom_check(d1, d2) )
> -        return xsm_grant_mapref(d1, d2, flags);
> +        return xsm_default_action(XSM_HOOK, d1, d2);
>      return -EPERM;
>  }
>  
>  static int silo_grant_transfer(struct domain *d1, struct domain *d2)
>  {
>      if ( silo_mode_dom_check(d1, d2) )
> -        return xsm_grant_transfer(d1, d2);
> +        return xsm_default_action(XSM_HOOK, d1, d2);
>      return -EPERM;
>  }
>  
>  static int silo_grant_copy(struct domain *d1, struct domain *d2)
>  {
>      if ( silo_mode_dom_check(d1, d2) )
> -        return xsm_grant_copy(d1, d2);
> +        return xsm_default_action(XSM_HOOK, d1, d2);
>      return -EPERM;
>  }
>  
> @@ -86,14 +87,14 @@ static int silo_argo_register_single_source(const struct domain *d1,
>                                              const struct domain *d2)
>  {
>      if ( silo_mode_dom_check(d1, d2) )
> -        return xsm_argo_register_single_source(d1, d2);
> +        return 0;
>      return -EPERM;
>  }
>  
>  static int silo_argo_send(const struct domain *d1, const struct domain *d2)
>  {
>      if ( silo_mode_dom_check(d1, d2) )
> -        return xsm_argo_send(d1, d2);
> +        return 0;

Shouldn't these be XSM_HOOK too?  Or should all other XSM_HOOK's be
short-circuted to 0?

The asymmetry here seems weird.

~Andrew