Re: [Xen-devel] [PATCH 09/11] xen: Add DOMCTL to limit the number of event channels a domain may use

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

On 09/27/2013 06:55 AM, David Vrabel wrote:
> From: David Vrabel <dvrabel@xxxxxxxxxx>
>
> Add XEN_DOMCTL_set_max_evtchn which may be used during domain creation to
> set the maximum event channel port a domain may use.  This may be used to
> limit the amount of Xen resources (global mapping space and xenheap) that
> a domain may use for event channels.
>
> A domain that does not have a limit set may use all the event channels
> supported by the event channel ABI in use.
>
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> Cc: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
> ---
[...]
> diff --git a/xen/xsm/flask/policy/access_vectors 
> b/xen/xsm/flask/policy/access_vectors
> index 5dfe13b..03a8e64 100644
> --- a/xen/xsm/flask/policy/access_vectors
> +++ b/xen/xsm/flask/policy/access_vectors
> @@ -157,6 +157,8 @@ class domain
>       set_misc_info
>   # XEN_DOMCTL_set_virq_handler
>       set_virq_handler
> +# XEN_DOMCTL_set_max_evtchn
> +    set_max_evtchn
>   }
>
>   # This is a continuation of class domain, since only 32 permissions can be
>   # defined per class
>   class domain2
The new domctl access vector must be added to the "domain2" class, not
"domain" which is full (already has 32 items). While the hypervisor
compilation does not currently report this as an error, attempting to
compile the policy (tools/flask/policy) will report it.

--
Daniel De Graaf
National Security Agency

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