diff mbox series

[v3,7/7] xsm: removing facade that XSM can be enabled/disabled

Message ID 20210805140644.357-8-dpsmith@apertussolutions.com (mailing list archive)
State Superseded
Headers show
Series xsm: refactoring xsm hooks | expand

Commit Message

Daniel P. Smith Aug. 5, 2021, 2:06 p.m. UTC
The XSM facilities are always in use by Xen with the facade of being able to
turn XSM on and off. This option is in fact about allowing the selection of
which policies are available and which are used at runtime.  To provide this
facade a complicated serious of #ifdef's are used to selective include
different headers or portions of headers. This series of #ifdef gyrations
switches between two different versions of the XSM hook interfaces and their
respective backing implementation.  All of this is done to provide a minimal
size/performance optimization for when alternative policies are disabled.

To unwind the #ifdef gyrations a series of changes were necessary,
    * replace CONFIG_XSM with XSM_CONFIGURABLE to allow visibility of
      selecting alternate XSM policy modules to those that require it
    * adjusted CONFIG_XSM_SILO, CONFIG_XSM_FLASK, and the default module
      selection to sensible defaults
    * collapsed the "dummy/defualt" XSM interface and implementation with the
      "multiple policy" interface to provide a single inlined implementation
      that attempts to use a registered hook and falls back to the check from
      the dummy implementation
    * the collapse to a single interface broke code relying on the alternate
      interface, specifically SILO, this was reworked to remove the
      indirection/abstraction making SILO explicit in its access control
      decisions
    * with the change of the XSM hooks to fall back to enforcing the dummy
      policy, it is no longer necessary to fill NULL entries in the struct
      xsm_ops returned by an XSM module's init

Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
---
 xen/common/Kconfig         |  47 +-
 xen/include/xsm/dummy.h    | 709 +----------------------------
 xen/include/xsm/xsm-core.h |  26 --
 xen/include/xsm/xsm.h      | 904 ++++++++++++++++++++++++++++---------
 xen/xsm/Makefile           |   3 +-
 xen/xsm/dummy.c            | 157 -------
 xen/xsm/silo.c             |  15 +-
 xen/xsm/xsm_core.c         |  18 +-
 8 files changed, 726 insertions(+), 1153 deletions(-)
 delete mode 100644 xen/xsm/dummy.c

Comments

Jan Beulich Aug. 26, 2021, 9:37 a.m. UTC | #1
On 05.08.2021 16:06, Daniel P. Smith wrote:
> The XSM facilities are always in use by Xen with the facade of being able to
> turn XSM on and off. This option is in fact about allowing the selection of
> which policies are available and which are used at runtime.  To provide this
> facade a complicated serious of #ifdef's are used to selective include

Nit: It took me a moment to realize that the sentence reads oddly because
you likely mean "series", not "serious".

> different headers or portions of headers. This series of #ifdef gyrations
> switches between two different versions of the XSM hook interfaces and their
> respective backing implementation.  All of this is done to provide a minimal
> size/performance optimization for when alternative policies are disabled.
> 
> To unwind the #ifdef gyrations a series of changes were necessary,
>     * replace CONFIG_XSM with XSM_CONFIGURABLE to allow visibility of
>       selecting alternate XSM policy modules to those that require it
>     * adjusted CONFIG_XSM_SILO, CONFIG_XSM_FLASK, and the default module
>       selection to sensible defaults
>     * collapsed the "dummy/defualt" XSM interface and implementation with the
>       "multiple policy" interface to provide a single inlined implementation
>       that attempts to use a registered hook and falls back to the check from
>       the dummy implementation
>     * the collapse to a single interface broke code relying on the alternate
>       interface, specifically SILO, this was reworked to remove the
>       indirection/abstraction making SILO explicit in its access control
>       decisions
>     * with the change of the XSM hooks to fall back to enforcing the dummy
>       policy, it is no longer necessary to fill NULL entries in the struct
>       xsm_ops returned by an XSM module's init

It would be nice if some of this could be split. Is this really close to
impossible?

> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -200,23 +200,15 @@ config XENOPROF
>  
>  	  If unsure, say Y.
>  
> -config XSM
> -	bool "Xen Security Modules support"
> -	default ARM
> -	---help---
> -	  Enables the security framework known as Xen Security Modules which
> -	  allows administrators fine-grained control over a Xen domain and
> -	  its capabilities by defining permissible interactions between domains,
> -	  the hypervisor itself, and related resources such as memory and
> -	  devices.
> -
> -	  If unsure, say N.
> +config XSM_CONFIGURABLE
> +    bool "Enable Configuring Xen Security Modules"

Is there a reason to change not only the prompt, but also the name of
the Kconfig setting? This alone is the reason for some otherwise
unnecessary code churn.

Also please correct indentation here.

>  config XSM_FLASK
> -	def_bool y
> -	prompt "FLux Advanced Security Kernel support"
> -	depends on XSM
> -	---help---
> +	bool "FLux Advanced Security Kernel support"
> +	default n

I don't understand this change in default (and as an aside, a default
of "n" doesn't need spelling out): In the description you say "adjusted
CONFIG_XSM_SILO, CONFIG_XSM_FLASK, and the default module selection to
sensible defaults". If that's to describe this change, then I'm afraid
I don't see why defaulting to "n" is more sensible once the person
configuring Xen has chosen the configure XSM's (or XSM_CONFIGURABLE's)
sub-options. If that's unrelated to the change here, then I'm afraid
I'm missing justification altogether. (Same for SILO then.)

> +	depends on XSM_CONFIGURABLE
> +	select XSM_EVTCHN_LABELING

Neither this nor any prior patch introduces an option of this name,
and there's also none in the present tree. All afaics; I may have
overlooked something or typo-ed a "grep" command.

> @@ -265,14 +258,14 @@ config XSM_SILO
>  	  If unsure, say Y.
>  
>  choice
> -	prompt "Default XSM implementation"
> -	depends on XSM
> +	prompt "Default XSM module"
>  	default XSM_SILO_DEFAULT if XSM_SILO && ARM
>  	default XSM_FLASK_DEFAULT if XSM_FLASK
>  	default XSM_SILO_DEFAULT if XSM_SILO
>  	default XSM_DUMMY_DEFAULT
> +	depends on XSM_CONFIGURABLE

With the larger set of "default" lines I'd like to suggest to keep
"depends on" ahead of them.

> @@ -282,7 +275,7 @@ endchoice
>  config LATE_HWDOM
>  	bool "Dedicated hardware domain"
>  	default n
> -	depends on XSM && X86
> +	depends on XSM_FLASK && X86

This change is not mentioned or justified in the description. In fact
I think it is unrelated to the change here and hence would want breaking
out.

>  	---help---

As you're changing these elsewhere, any chance of you also changing
this one to just "help"?

> --- a/xen/include/xsm/xsm.h
> +++ b/xen/include/xsm/xsm.h
> @@ -19,545 +19,1023 @@
>  #include <xen/sched.h>
>  #include <xen/multiboot.h>
>  #include <xsm/xsm-core.h>
> -
> -#ifdef CONFIG_XSM
> +#include <xsm/dummy.h>
> +#include <public/version.h>
>  
>  extern struct xsm_ops xsm_ops;
>  
> -static inline void xsm_security_domaininfo (struct domain *d,
> -                                        struct xen_domctl_getdomaininfo *info)
> +static inline void xsm_security_domaininfo(
> +    struct domain *d,
> +    struct xen_domctl_getdomaininfo *info)
>  {
> -    alternative_vcall(xsm_ops.security_domaininfo, d, info);
> +    if ( xsm_ops.security_domaininfo )
> +        alternative_vcall(xsm_ops.security_domaininfo, d, info);

Here and everywhere else, when !XSM_CONFIGURABLE you now needlessly
force NULL checks to occur which are never going to be true. There's
then also the dead indirect call and the associated patching data. I
think this wants hiding in another pair of wrappers, which simply
expand to nothing when !XSM_CONFIGURABLE - perhaps xsm_vcall() and
xsm_call().

>  }
>  
> -static inline int xsm_domain_create (xsm_default_t def, struct domain *d, u32 ssidref)
> +static inline int xsm_domain_create(xsm_default_t action, struct domain *d,
> +                                    u32 ssidref)

It would be nice if you kept on converting u32 -> uint32_t as you did
in earlier patches.

>  {
> -    return alternative_call(xsm_ops.domain_create, d, ssidref);
> +    if ( xsm_ops.domain_create )
> +        return alternative_call(xsm_ops.domain_create, d, ssidref);
> +
> +    XSM_ASSERT_ACTION(XSM_HOOK);

Any reason not to put these assertions first in the functions?

> +    return xsm_default_action(action, current->domain, d);
>  }

Since

static inline int xsm_domain_create(xsm_default_t action, struct domain *d,
                                    uint32_t ssidref)
{
    XSM_ASSERT_ACTION(XSM_HOOK);
    return xsm_call(xsm_ops.domain_create, d, ssidref);
    return xsm_default_action(action, current->domain, d);
}

won't work, and since integrating "return" into xsm_call() also would't
yield a sufficiently clear result:

static inline int xsm_domain_create(xsm_default_t action, struct domain *d,
                                    uint32_t ssidref)
{
    XSM_ASSERT_ACTION(XSM_HOOK);
    xsm_call(xsm_ops.domain_create, d, ssidref);
    return xsm_default_action(action, current->domain, d);
}

(as control flow would be unobvious), the xsm_default_action() invocation
likely would also need integrating into xsm_call() then.

Unless there's some obstacle, this would eliminate a whole lot of code
redundancy.

> -static inline int xsm_set_target (xsm_default_t def, struct domain *d, struct domain *e)
> +static inline int xsm_set_target(xsm_default_t action, struct domain *d,
> +                                 struct domain *e)
>  {
> -    return alternative_call(xsm_ops.set_target, d, e);
> +    if ( xsm_ops.set_target )
> +        return alternative_call(xsm_ops.set_target, d, e);
> +
> +    XSM_ASSERT_ACTION(XSM_HOOK);
> +    return xsm_default_action(action, current->domain, NULL);
>  }

While benign because xsm_default_action() does nothing for XSM_HOOK, I
think there's an inconsistency here which rather wants correcting (in
a prereq patch): The default hook should have been passed consistent
arguments, no matter whether used because of !XSM or because of the
module in use left the hook unset.

Of course such anomalies are much easier to notice (outside of review
of patches introducing such) with you now placing both invocations
next to each other.

> -static inline int xsm_evtchn_interdomain (xsm_default_t def, struct domain *d1,
> -                struct evtchn *chan1, struct domain *d2, struct evtchn *chan2)
> +static inline int xsm_evtchn_interdomain(xsm_default_t action,
> +                                         struct domain *d1,
> +                                         struct evtchn *chan1,
> +                                         struct domain *d2,
> +                                         struct evtchn *chan2)
>  {
> -    return alternative_call(xsm_ops.evtchn_interdomain, d1, chan1, d2, chan2);
> +    if ( xsm_ops.evtchn_interdomain )
> +        return alternative_call(xsm_ops.evtchn_interdomain, d1, chan1, d2,
> +                                chan2);
> +
> +    XSM_ASSERT_ACTION(XSM_HOOK);
> +    return xsm_default_action(action, d1, d2);
>  }

There's another anomaly here: The first argument to xsm_default_action()
typically is current->domain in similar functions. Here d1 gets passed in
despite always being current->domain. I think the unnecessary parameter
wants dropping (again in a prereq patch)) from the wrapper and hook, to
avoid giving the wrong impression of both domains potentially being remote
ones.

> -static inline int xsm_evtchn_send (xsm_default_t def, struct domain *d, struct evtchn *chn)
> +static inline int xsm_evtchn_send(xsm_default_t action, struct domain *d,
> +                                  struct evtchn *chn)
>  {
> -    return alternative_call(xsm_ops.evtchn_send, d, chn);
> +    if ( xsm_ops.evtchn_send )
> +        return alternative_call(xsm_ops.evtchn_send, d, chn);
> +
> +    XSM_ASSERT_ACTION(XSM_HOOK);
> +    return xsm_default_action(action, d, NULL);

This again looks wrong (and again is benign only because XSM_HOOK means
xsm_default_action() ignores the other function parameters), wanting to
follow the usual

    return xsm_default_action(action, current->domain, d);

pattern instead.

> -static inline int xsm_evtchn_reset (xsm_default_t def, struct domain *d1, struct domain *d2)
> +static inline int xsm_evtchn_reset(xsm_default_t action, struct domain *d1,
> +                                   struct domain *d2)
>  {
> -    return alternative_call(xsm_ops.evtchn_reset, d1, d2);
> +    if ( xsm_ops.evtchn_reset )
> +        return alternative_call(xsm_ops.evtchn_reset, d1, d2);
> +
> +    XSM_ASSERT_ACTION(XSM_TARGET);
> +    return xsm_default_action(action, d1, d2);

See xsm_evtchn_interdomain() above.

> -static inline int xsm_grant_mapref (xsm_default_t def, struct domain *d1, struct domain *d2,
> -                                                                uint32_t flags)
> +static inline int xsm_grant_mapref(xsm_default_t action, struct domain *d1,
> +                                   struct domain *d2, uint32_t flags)
>  {
> -    return alternative_call(xsm_ops.grant_mapref, d1, d2, flags);
> +    if ( xsm_ops.grant_mapref )
> +        return alternative_call(xsm_ops.grant_mapref, d1, d2, flags);
> +
> +    XSM_ASSERT_ACTION(XSM_HOOK);
> +    return xsm_default_action(action, d1, d2);

Again (more similar grant ones follow).

> -static inline int xsm_memory_adjust_reservation (xsm_default_t def, struct domain *d1, struct
> -                                                                    domain *d2)
> +static inline int xsm_memory_adjust_reservation(xsm_default_t action,
> +                                                struct domain *d1,
> +                                                struct domain *d2)
>  {
> -    return alternative_call(xsm_ops.memory_adjust_reservation, d1, d2);
> +    if ( xsm_ops.memory_adjust_reservation )
> +        return alternative_call(xsm_ops.memory_adjust_reservation, d1, d2);
> +
> +    XSM_ASSERT_ACTION(XSM_TARGET);
> +    return xsm_default_action(action, d1, d2);

Again (more similar memory ones follow).

> -static inline int xsm_memory_pin_page(xsm_default_t def, struct domain *d1, struct domain *d2,
> -                                      struct page_info *page)
> +static inline int xsm_memory_pin_page(xsm_default_t action, struct domain *d1,
> +                                      struct domain *d2, struct page_info *page)
>  {
> -    return alternative_call(xsm_ops.memory_pin_page, d1, d2, page);
> +    if ( xsm_ops.memory_pin_page )
> +        return alternative_call(xsm_ops.memory_pin_page, d1, d2, page);
> +
> +    XSM_ASSERT_ACTION(XSM_HOOK);
> +    return xsm_default_action(action, d1, d2);

This one has the same issue, but is more interesting: There's no
similar hook/check for unpinning a page (nor does the same check
get re-used there). Plus it's x86 (more precisely PV) specific.

> -static inline int xsm_map_gmfn_foreign (xsm_default_t def, struct domain *d, struct domain *t)
> +static inline int xsm_map_gmfn_foreign(xsm_default_t action, struct domain *d,
> +                                       struct domain *t)
>  {
> -    return alternative_call(xsm_ops.map_gmfn_foreign, d, t);
> +    if ( xsm_ops.map_gmfn_foreign )
> +        return alternative_call(xsm_ops.map_gmfn_foreign, d, t);
> +
> +    XSM_ASSERT_ACTION(XSM_TARGET);
> +    return xsm_default_action(action, d, t);

This one is also interesting: There's no check at all here that
current->domain has any permissions towards d or t. Interestingly
even flask_map_gmfn_foreign() doesn't check this.

> -static inline int xsm_console_io (xsm_default_t def, struct domain *d, int cmd)
> +static inline int xsm_console_io(xsm_default_t action, struct domain *d, int cmd)
>  {
> -    return alternative_call(xsm_ops.console_io, d, cmd);
> +    if ( xsm_ops.console_io )
> +        return alternative_call(xsm_ops.console_io, d, cmd);
> +
> +    XSM_ASSERT_ACTION(XSM_OTHER);
> +    if ( d->is_console )
> +        return xsm_default_action(XSM_HOOK, d, NULL);
> +#ifdef CONFIG_VERBOSE_DEBUG
> +    if ( cmd == CONSOLEIO_write )
> +        return xsm_default_action(XSM_HOOK, d, NULL);
> +#endif
> +    return xsm_default_action(XSM_PRIV, d, NULL);

Same implication of d == current->domain here again. I guess I'll
stop enumerating further ones.

> -static inline int xsm_pci_config_permission (xsm_default_t def, struct domain *d, uint32_t machine_bdf, uint16_t start, uint16_t end, uint8_t access)
> +static inline int xsm_pci_config_permission(xsm_default_t action,
> +                                            struct domain *d,
> +                                            uint32_t machine_bdf,
> +                                            uint16_t start,
> +                                            uint16_t end,
> +                                            uint8_t access)
>  {
> -    return alternative_call(xsm_ops.pci_config_permission, d, machine_bdf, start, end, access);
> +    if ( xsm_ops.pci_config_permission )
> +        return alternative_call(xsm_ops.pci_config_permission, d, machine_bdf, start, end, access);

Nit: Line length.

> -static inline int xsm_pmu_op (xsm_default_t def, struct domain *d, unsigned int op)
> +static inline int xsm_pmu_op(xsm_default_t action, struct domain *d,
> +                             unsigned int op)
>  {
> -    return alternative_call(xsm_ops.pmu_op, d, op);
> +    if ( xsm_ops.pmu_op )
> +        return alternative_call(xsm_ops.pmu_op, d, op);
> +
> +    XSM_ASSERT_ACTION(XSM_OTHER);
> +    switch ( op )
> +    {
> +    case XENPMU_init:
> +    case XENPMU_finish:
> +    case XENPMU_lvtpc_set:
> +    case XENPMU_flush:
> +        return xsm_default_action(XSM_HOOK, d, current->domain);
> +    default:
> +        return xsm_default_action(XSM_PRIV, d, current->domain);

Urgh - isn't this the wrong way round? (Luckily vPMU isn't security
supported, so no XSA would be needed.)

> --- a/xen/xsm/Makefile
> +++ b/xen/xsm/Makefile
> @@ -1,6 +1,5 @@
>  obj-y += xsm_core.o
> -obj-$(CONFIG_XSM) += xsm_policy.o
> -obj-$(CONFIG_XSM) += dummy.o
> +obj-y += xsm_policy.o

Why would this now need compiling in all cases?

> --- 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>

As already mentioned elsewhere - where possible please arrange #include-s
alphabetically.

> @@ -124,16 +122,12 @@ static int __init xsm_core_init(const void *policy_buffer, size_t policy_size)
>          break;
>      }
>  
> -    /*
> -     * This handles three cases,
> -     *   - dummy policy module was selected
> -     *   - a policy module does not provide all handlers
> -     *   - a policy module failed to init
> -     */
> -    xsm_fixup_ops(&xsm_ops);
> -
> -    if ( xsm_ops_registered != XSM_OPS_REGISTERED )
> +    if ( xsm_ops_registered != XSM_OPS_REGISTERED ) {

Nit (style): Brace goes on its own line.

Jan
Daniel P. Smith Aug. 30, 2021, 12:11 p.m. UTC | #2
On 8/26/21 5:37 AM, Jan Beulich wrote:
> On 05.08.2021 16:06, Daniel P. Smith wrote:
>> The XSM facilities are always in use by Xen with the facade of being able to
>> turn XSM on and off. This option is in fact about allowing the selection of
>> which policies are available and which are used at runtime.  To provide this
>> facade a complicated serious of #ifdef's are used to selective include
> 
> Nit: It took me a moment to realize that the sentence reads oddly because
> you likely mean "series", not "serious".
> 
>> different headers or portions of headers. This series of #ifdef gyrations
>> switches between two different versions of the XSM hook interfaces and their
>> respective backing implementation.  All of this is done to provide a minimal
>> size/performance optimization for when alternative policies are disabled.
>>
>> To unwind the #ifdef gyrations a series of changes were necessary,
>>     * replace CONFIG_XSM with XSM_CONFIGURABLE to allow visibility of
>>       selecting alternate XSM policy modules to those that require it
>>     * adjusted CONFIG_XSM_SILO, CONFIG_XSM_FLASK, and the default module
>>       selection to sensible defaults
>>     * collapsed the "dummy/defualt" XSM interface and implementation with the
>>       "multiple policy" interface to provide a single inlined implementation
>>       that attempts to use a registered hook and falls back to the check from
>>       the dummy implementation
>>     * the collapse to a single interface broke code relying on the alternate
>>       interface, specifically SILO, this was reworked to remove the
>>       indirection/abstraction making SILO explicit in its access control
>>       decisions
>>     * with the change of the XSM hooks to fall back to enforcing the dummy
>>       policy, it is no longer necessary to fill NULL entries in the struct
>>       xsm_ops returned by an XSM module's init
> 
> It would be nice if some of this could be split. Is this really close to
> impossible?

I am looking into that now, especially after my points below.

>> --- a/xen/common/Kconfig
>> +++ b/xen/common/Kconfig
>> @@ -200,23 +200,15 @@ config XENOPROF
>>  
>>  	  If unsure, say Y.
>>  
>> -config XSM
>> -	bool "Xen Security Modules support"
>> -	default ARM
>> -	---help---
>> -	  Enables the security framework known as Xen Security Modules which
>> -	  allows administrators fine-grained control over a Xen domain and
>> -	  its capabilities by defining permissible interactions between domains,
>> -	  the hypervisor itself, and related resources such as memory and
>> -	  devices.
>> -
>> -	  If unsure, say N.
>> +config XSM_CONFIGURABLE
>> +    bool "Enable Configuring Xen Security Modules"
> 
> Is there a reason to change not only the prompt, but also the name of
> the Kconfig setting? This alone is the reason for some otherwise
> unnecessary code churn.

Yes, because this idea of "turning off" XSM needs to end externally and
internally. The XSM framework is always being used, it's just that it is
possible to build a configuration with support only for the
default/dummy policy, regardless of how the functions implementing the
default/dummy policy are being invoked.

> Also please correct indentation here.

Ack.

>>  config XSM_FLASK
>> -	def_bool y
>> -	prompt "FLux Advanced Security Kernel support"
>> -	depends on XSM
>> -	---help---
>> +	bool "FLux Advanced Security Kernel support"
>> +	default n
> 
> I don't understand this change in default (and as an aside, a default
> of "n" doesn't need spelling out): In the description you say "adjusted
> CONFIG_XSM_SILO, CONFIG_XSM_FLASK, and the default module selection to
> sensible defaults". If that's to describe this change, then I'm afraid
> I don't see why defaulting to "n" is more sensible once the person
> configuring Xen has chosen the configure XSM's (or XSM_CONFIGURABLE's)
> sub-options. If that's unrelated to the change here, then I'm afraid
> I'm missing justification altogether. (Same for SILO then.)

When an individual selects to be able to be to configure/select
alternative policy modules, they should be the ones to decide which
one(s) should be enabled and not have presumptuous selections provided
to them. IOW, the sensible default is to have no modules selected and
allow the user to enable the one(s) they want.

>> +	depends on XSM_CONFIGURABLE
>> +	select XSM_EVTCHN_LABELING
> 
> Neither this nor any prior patch introduces an option of this name,
> and there's also none in the present tree. All afaics; I may have
> overlooked something or typo-ed a "grep" command.

Ack, missed this in the previous patch. will clean it up there.

>> @@ -265,14 +258,14 @@ config XSM_SILO
>>  	  If unsure, say Y.
>>  
>>  choice
>> -	prompt "Default XSM implementation"
>> -	depends on XSM
>> +	prompt "Default XSM module"
>>  	default XSM_SILO_DEFAULT if XSM_SILO && ARM
>>  	default XSM_FLASK_DEFAULT if XSM_FLASK
>>  	default XSM_SILO_DEFAULT if XSM_SILO
>>  	default XSM_DUMMY_DEFAULT
>> +	depends on XSM_CONFIGURABLE
> 
> With the larger set of "default" lines I'd like to suggest to keep

Ack.

>> @@ -282,7 +275,7 @@ endchoice
>>  config LATE_HWDOM
>>  	bool "Dedicated hardware domain"
>>  	default n
>> -	depends on XSM && X86
>> +	depends on XSM_FLASK && X86
> 
> This change is not mentioned or justified in the description. In fact
> I think it is unrelated to the change here and hence would want breaking
> out.

Actually, if you read the help just below it specifically says to use
this feature requires having an XSM policy (legacy wording for XSM Flask
policy) to be able to do the proper fine grained delegation of the
permissions/accesses necessary for a hardware domain to work. This
should have been made XSM_FLASK when that KConfig option was added.
Dropping the XSM KConfig option just exposed this oversight. Ack that I
should have mentioned this in the commit message.

>>  	---help---
> 
> As you're changing these elsewhere, any chance of you also changing
> this one to just "help"?

Ack.

>> --- a/xen/include/xsm/xsm.h
>> +++ b/xen/include/xsm/xsm.h
>> @@ -19,545 +19,1023 @@
>>  #include <xen/sched.h>
>>  #include <xen/multiboot.h>
>>  #include <xsm/xsm-core.h>
>> -
>> -#ifdef CONFIG_XSM
>> +#include <xsm/dummy.h>
>> +#include <public/version.h>
>>  
>>  extern struct xsm_ops xsm_ops;
>>  
>> -static inline void xsm_security_domaininfo (struct domain *d,
>> -                                        struct xen_domctl_getdomaininfo *info)
>> +static inline void xsm_security_domaininfo(
>> +    struct domain *d,
>> +    struct xen_domctl_getdomaininfo *info)
>>  {
>> -    alternative_vcall(xsm_ops.security_domaininfo, d, info);
>> +    if ( xsm_ops.security_domaininfo )
>> +        alternative_vcall(xsm_ops.security_domaininfo, d, info);
> 
> Here and everywhere else, when !XSM_CONFIGURABLE you now needlessly
> force NULL checks to occur which are never going to be true. There's
> then also the dead indirect call and the associated patching data. I
> think this wants hiding in another pair of wrappers, which simply
> expand to nothing when !XSM_CONFIGURABLE - perhaps xsm_vcall() and
> xsm_call().


This has now come back full circle to the attempts made in v1 at
addressing the RFC comments collected at the developer's summit. The
calls xsm_vcall and xsm_call will not be simple since the different xsm
hooks take a different number of arguments. Therefore these calls will
have to become a series of macros to handle the varying number of
arguments, similar to alternative_call and elsewhere but instead of
being general purpose for use throughout the hypervisor they will create
a complication in the code that is dedicated to a single file under XSM.
Outside of a demonstrable significant performance impact that can be
measured, the goal for security relevant code should be simplicity and
ability to reason about correctness. Therefore without a demonstration
that there is an actual performance impact simplicity should be the goal
here, especially considering this effort has unmasked potential bugs
noted below that were masked by this kind of complication.

With that I would like to withdraw this patch and spin a v4 of this
patch set with that revives the dropping of the inlines done similar to
v1/v2. As requested above, I will look to see if any of the changes that
still applies could be split into dedicated commits.

<snip>

>> -static inline int xsm_set_target (xsm_default_t def, struct domain *d, struct domain *e)
>> +static inline int xsm_set_target(xsm_default_t action, struct domain *d,
>> +                                 struct domain *e)
>>  {
>> -    return alternative_call(xsm_ops.set_target, d, e);
>> +    if ( xsm_ops.set_target )
>> +        return alternative_call(xsm_ops.set_target, d, e);
>> +
>> +    XSM_ASSERT_ACTION(XSM_HOOK);
>> +    return xsm_default_action(action, current->domain, NULL);
>>  }
> 
> While benign because xsm_default_action() does nothing for XSM_HOOK, I
> think there's an inconsistency here which rather wants correcting (in
> a prereq patch): The default hook should have been passed consistent
> arguments, no matter whether used because of !XSM or because of the
> module in use left the hook unset.
> 
> Of course such anomalies are much easier to notice (outside of review
> of patches introducing such) with you now placing both invocations
> next to each other.

This series assumes the logic is correct and is only focused on trying
to make XSM more maintainable. I would be glad to consider looking at
what the right security decisions should be in a subsequent patch set
but will be consider out of scope for this patch set.

>> -static inline int xsm_evtchn_interdomain (xsm_default_t def, struct domain *d1,
>> -                struct evtchn *chan1, struct domain *d2, struct evtchn *chan2)
>> +static inline int xsm_evtchn_interdomain(xsm_default_t action,
>> +                                         struct domain *d1,
>> +                                         struct evtchn *chan1,
>> +                                         struct domain *d2,
>> +                                         struct evtchn *chan2)
>>  {
>> -    return alternative_call(xsm_ops.evtchn_interdomain, d1, chan1, d2, chan2);
>> +    if ( xsm_ops.evtchn_interdomain )
>> +        return alternative_call(xsm_ops.evtchn_interdomain, d1, chan1, d2,
>> +                                chan2);
>> +
>> +    XSM_ASSERT_ACTION(XSM_HOOK);
>> +    return xsm_default_action(action, d1, d2);
>>  }
> 
> There's another anomaly here: The first argument to xsm_default_action()
> typically is current->domain in similar functions. Here d1 gets passed in
> despite always being current->domain. I think the unnecessary parameter
> wants dropping (again in a prereq patch)) from the wrapper and hook, to
> avoid giving the wrong impression of both domains potentially being remote
> ones.

out of scope

>> -static inline int xsm_evtchn_send (xsm_default_t def, struct domain *d, struct evtchn *chn)
>> +static inline int xsm_evtchn_send(xsm_default_t action, struct domain *d,
>> +                                  struct evtchn *chn)
>>  {
>> -    return alternative_call(xsm_ops.evtchn_send, d, chn);
>> +    if ( xsm_ops.evtchn_send )
>> +        return alternative_call(xsm_ops.evtchn_send, d, chn);
>> +
>> +    XSM_ASSERT_ACTION(XSM_HOOK);
>> +    return xsm_default_action(action, d, NULL);
> 
> This again looks wrong (and again is benign only because XSM_HOOK means
> xsm_default_action() ignores the other function parameters), wanting to
> follow the usual
> 
>     return xsm_default_action(action, current->domain, d);
> 
> pattern instead.

out of scope

>> -static inline int xsm_evtchn_reset (xsm_default_t def, struct domain *d1, struct domain *d2)
>> +static inline int xsm_evtchn_reset(xsm_default_t action, struct domain *d1,
>> +                                   struct domain *d2)
>>  {
>> -    return alternative_call(xsm_ops.evtchn_reset, d1, d2);
>> +    if ( xsm_ops.evtchn_reset )
>> +        return alternative_call(xsm_ops.evtchn_reset, d1, d2);
>> +
>> +    XSM_ASSERT_ACTION(XSM_TARGET);
>> +    return xsm_default_action(action, d1, d2);
> 
> See xsm_evtchn_interdomain() above.

out of scope

>> -static inline int xsm_grant_mapref (xsm_default_t def, struct domain *d1, struct domain *d2,
>> -                                                                uint32_t flags)
>> +static inline int xsm_grant_mapref(xsm_default_t action, struct domain *d1,
>> +                                   struct domain *d2, uint32_t flags)
>>  {
>> -    return alternative_call(xsm_ops.grant_mapref, d1, d2, flags);
>> +    if ( xsm_ops.grant_mapref )
>> +        return alternative_call(xsm_ops.grant_mapref, d1, d2, flags);
>> +
>> +    XSM_ASSERT_ACTION(XSM_HOOK);
>> +    return xsm_default_action(action, d1, d2);
> 
> Again (more similar grant ones follow).

out of scope

>> -static inline int xsm_memory_adjust_reservation (xsm_default_t def, struct domain *d1, struct
>> -                                                                    domain *d2)
>> +static inline int xsm_memory_adjust_reservation(xsm_default_t action,
>> +                                                struct domain *d1,
>> +                                                struct domain *d2)
>>  {
>> -    return alternative_call(xsm_ops.memory_adjust_reservation, d1, d2);
>> +    if ( xsm_ops.memory_adjust_reservation )
>> +        return alternative_call(xsm_ops.memory_adjust_reservation, d1, d2);
>> +
>> +    XSM_ASSERT_ACTION(XSM_TARGET);
>> +    return xsm_default_action(action, d1, d2);
> 
> Again (more similar memory ones follow).

out of scope

>> -static inline int xsm_memory_pin_page(xsm_default_t def, struct domain *d1, struct domain *d2,
>> -                                      struct page_info *page)
>> +static inline int xsm_memory_pin_page(xsm_default_t action, struct domain *d1,
>> +                                      struct domain *d2, struct page_info *page)
>>  {
>> -    return alternative_call(xsm_ops.memory_pin_page, d1, d2, page);
>> +    if ( xsm_ops.memory_pin_page )
>> +        return alternative_call(xsm_ops.memory_pin_page, d1, d2, page);
>> +
>> +    XSM_ASSERT_ACTION(XSM_HOOK);
>> +    return xsm_default_action(action, d1, d2);
> 
> This one has the same issue, but is more interesting: There's no
> similar hook/check for unpinning a page (nor does the same check
> get re-used there). Plus it's x86 (more precisely PV) specific.

out of scope

>> -static inline int xsm_map_gmfn_foreign (xsm_default_t def, struct domain *d, struct domain *t)
>> +static inline int xsm_map_gmfn_foreign(xsm_default_t action, struct domain *d,
>> +                                       struct domain *t)
>>  {
>> -    return alternative_call(xsm_ops.map_gmfn_foreign, d, t);
>> +    if ( xsm_ops.map_gmfn_foreign )
>> +        return alternative_call(xsm_ops.map_gmfn_foreign, d, t);
>> +
>> +    XSM_ASSERT_ACTION(XSM_TARGET);
>> +    return xsm_default_action(action, d, t);
> 
> This one is also interesting: There's no check at all here that
> current->domain has any permissions towards d or t. Interestingly
> even flask_map_gmfn_foreign() doesn't check this.

out of scope

>> -static inline int xsm_console_io (xsm_default_t def, struct domain *d, int cmd)
>> +static inline int xsm_console_io(xsm_default_t action, struct domain *d, int cmd)
>>  {
>> -    return alternative_call(xsm_ops.console_io, d, cmd);
>> +    if ( xsm_ops.console_io )
>> +        return alternative_call(xsm_ops.console_io, d, cmd);
>> +
>> +    XSM_ASSERT_ACTION(XSM_OTHER);
>> +    if ( d->is_console )
>> +        return xsm_default_action(XSM_HOOK, d, NULL);
>> +#ifdef CONFIG_VERBOSE_DEBUG
>> +    if ( cmd == CONSOLEIO_write )
>> +        return xsm_default_action(XSM_HOOK, d, NULL);
>> +#endif
>> +    return xsm_default_action(XSM_PRIV, d, NULL);
> 
> Same implication of d == current->domain here again. I guess I'll
> stop enumerating further ones.

out of scope

<snip>

>> -static inline int xsm_pmu_op (xsm_default_t def, struct domain *d, unsigned int op)
>> +static inline int xsm_pmu_op(xsm_default_t action, struct domain *d,
>> +                             unsigned int op)
>>  {
>> -    return alternative_call(xsm_ops.pmu_op, d, op);
>> +    if ( xsm_ops.pmu_op )
>> +        return alternative_call(xsm_ops.pmu_op, d, op);
>> +
>> +    XSM_ASSERT_ACTION(XSM_OTHER);
>> +    switch ( op )
>> +    {
>> +    case XENPMU_init:
>> +    case XENPMU_finish:
>> +    case XENPMU_lvtpc_set:
>> +    case XENPMU_flush:
>> +        return xsm_default_action(XSM_HOOK, d, current->domain);
>> +    default:
>> +        return xsm_default_action(XSM_PRIV, d, current->domain);
> 
> Urgh - isn't this the wrong way round? (Luckily vPMU isn't security
> supported, so no XSA would be needed.)

out of scope

<snip>

>> --- 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>
> 
> As already mentioned elsewhere - where possible please arrange #include-s
> alphabetically.

Ack.

>> @@ -124,16 +122,12 @@ static int __init xsm_core_init(const void *policy_buffer, size_t policy_size)
>>          break;
>>      }
>>  
>> -    /*
>> -     * This handles three cases,
>> -     *   - dummy policy module was selected
>> -     *   - a policy module does not provide all handlers
>> -     *   - a policy module failed to init
>> -     */
>> -    xsm_fixup_ops(&xsm_ops);
>> -
>> -    if ( xsm_ops_registered != XSM_OPS_REGISTERED )
>> +    if ( xsm_ops_registered != XSM_OPS_REGISTERED ) {
> 
> Nit (style): Brace goes on its own line.

Ack

v/r,
dps
Jan Beulich Aug. 30, 2021, 1:34 p.m. UTC | #3
On 30.08.2021 14:11, Daniel P. Smith wrote:
> On 8/26/21 5:37 AM, Jan Beulich wrote:
>> On 05.08.2021 16:06, Daniel P. Smith wrote:
>>>  config XSM_FLASK
>>> -	def_bool y
>>> -	prompt "FLux Advanced Security Kernel support"
>>> -	depends on XSM
>>> -	---help---
>>> +	bool "FLux Advanced Security Kernel support"
>>> +	default n
>>
>> I don't understand this change in default (and as an aside, a default
>> of "n" doesn't need spelling out): In the description you say "adjusted
>> CONFIG_XSM_SILO, CONFIG_XSM_FLASK, and the default module selection to
>> sensible defaults". If that's to describe this change, then I'm afraid
>> I don't see why defaulting to "n" is more sensible once the person
>> configuring Xen has chosen the configure XSM's (or XSM_CONFIGURABLE's)
>> sub-options. If that's unrelated to the change here, then I'm afraid
>> I'm missing justification altogether. (Same for SILO then.)
> 
> When an individual selects to be able to be to configure/select
> alternative policy modules, they should be the ones to decide which
> one(s) should be enabled and not have presumptuous selections provided
> to them. IOW, the sensible default is to have no modules selected and
> allow the user to enable the one(s) they want.

Just FTR - I disagree. Defaults should be such that a majority would
not need to alter the respective settings.

>>> @@ -282,7 +275,7 @@ endchoice
>>>  config LATE_HWDOM
>>>  	bool "Dedicated hardware domain"
>>>  	default n
>>> -	depends on XSM && X86
>>> +	depends on XSM_FLASK && X86
>>
>> This change is not mentioned or justified in the description. In fact
>> I think it is unrelated to the change here and hence would want breaking
>> out.
> 
> Actually, if you read the help just below it specifically says to use
> this feature requires having an XSM policy (legacy wording for XSM Flask
> policy) to be able to do the proper fine grained delegation of the
> permissions/accesses necessary for a hardware domain to work. This
> should have been made XSM_FLASK when that KConfig option was added.
> Dropping the XSM KConfig option just exposed this oversight. Ack that I
> should have mentioned this in the commit message.

I'm getting the impression that you mistook "breaking out" for "dropping".
I can see the point of the change; it merely shouldn't be hidden in this
otherwise unrelated much larger change.

>>> -static inline int xsm_set_target (xsm_default_t def, struct domain *d, struct domain *e)
>>> +static inline int xsm_set_target(xsm_default_t action, struct domain *d,
>>> +                                 struct domain *e)
>>>  {
>>> -    return alternative_call(xsm_ops.set_target, d, e);
>>> +    if ( xsm_ops.set_target )
>>> +        return alternative_call(xsm_ops.set_target, d, e);
>>> +
>>> +    XSM_ASSERT_ACTION(XSM_HOOK);
>>> +    return xsm_default_action(action, current->domain, NULL);
>>>  }
>>
>> While benign because xsm_default_action() does nothing for XSM_HOOK, I
>> think there's an inconsistency here which rather wants correcting (in
>> a prereq patch): The default hook should have been passed consistent
>> arguments, no matter whether used because of !XSM or because of the
>> module in use left the hook unset.
>>
>> Of course such anomalies are much easier to notice (outside of review
>> of patches introducing such) with you now placing both invocations
>> next to each other.
> 
> This series assumes the logic is correct and is only focused on trying
> to make XSM more maintainable. I would be glad to consider looking at
> what the right security decisions should be in a subsequent patch set
> but will be consider out of scope for this patch set.

Well, I came to make these comments because these anomalies look to
stand in the way of producing a sufficiently small set of wrapper /
helper macros. But since you want to go back to an older version's
approach, the need to correct these as a (series of) prereq(s) may
indeed vanish.

Jan
diff mbox series

Patch

diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index ac5491b1cc..3c5980a336 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -200,23 +200,15 @@  config XENOPROF
 
 	  If unsure, say Y.
 
-config XSM
-	bool "Xen Security Modules support"
-	default ARM
-	---help---
-	  Enables the security framework known as Xen Security Modules which
-	  allows administrators fine-grained control over a Xen domain and
-	  its capabilities by defining permissible interactions between domains,
-	  the hypervisor itself, and related resources such as memory and
-	  devices.
-
-	  If unsure, say N.
+config XSM_CONFIGURABLE
+    bool "Enable Configuring Xen Security Modules"
 
 config XSM_FLASK
-	def_bool y
-	prompt "FLux Advanced Security Kernel support"
-	depends on XSM
-	---help---
+	bool "FLux Advanced Security Kernel support"
+	default n
+	depends on XSM_CONFIGURABLE
+	select XSM_EVTCHN_LABELING
+	help
 	  Enables FLASK (FLux Advanced Security Kernel) as the access control
 	  mechanism used by the XSM framework.  This provides a mandatory access
 	  control framework by which security enforcement, isolation, and
@@ -226,10 +218,10 @@  config XSM_FLASK
 	  If unsure, say Y.
 
 config XSM_FLASK_AVC_STATS
-	def_bool y
-	prompt "Maintain statistics on the FLASK access vector cache" if EXPERT
+	bool "Maintain statistics on the FLASK access vector cache" if EXPERT
+	default y
 	depends on XSM_FLASK
-	---help---
+	help
 	  Maintain counters on the access vector cache that can be viewed using
 	  the FLASK_AVC_CACHESTATS sub-op of the xsm_op hypercall.  Disabling
 	  this will save a tiny amount of memory and time to update the stats.
@@ -240,7 +232,7 @@  config XSM_FLASK_POLICY
 	bool "Compile Xen with a built-in FLASK security policy"
 	default y if "$(XEN_HAS_CHECKPOLICY)" = "y"
 	depends on XSM_FLASK
-	---help---
+	help
 	  This includes a default XSM policy in the hypervisor so that the
 	  bootloader does not need to load a policy to get sane behavior from an
 	  XSM-enabled hypervisor.  If this is disabled, a policy must be
@@ -253,10 +245,11 @@  config XSM_FLASK_POLICY
 	  If unsure, say Y.
 
 config XSM_SILO
-	def_bool y
-	prompt "SILO support"
-	depends on XSM
-	---help---
+	bool "SILO support"
+	default y if ARM
+	default n
+	depends on XSM_CONFIGURABLE
+	help
 	  Enables SILO as the access control mechanism used by the XSM framework.
 	  This is not the default module, add boot parameter xsm=silo to choose
 	  it. This will deny any unmediated communication channels (grant tables
@@ -265,14 +258,14 @@  config XSM_SILO
 	  If unsure, say Y.
 
 choice
-	prompt "Default XSM implementation"
-	depends on XSM
+	prompt "Default XSM module"
 	default XSM_SILO_DEFAULT if XSM_SILO && ARM
 	default XSM_FLASK_DEFAULT if XSM_FLASK
 	default XSM_SILO_DEFAULT if XSM_SILO
 	default XSM_DUMMY_DEFAULT
+	depends on XSM_CONFIGURABLE
 	config XSM_DUMMY_DEFAULT
-		bool "Match non-XSM behavior"
+		bool "Classic Dom0 behavior"
 	config XSM_FLASK_DEFAULT
 		bool "FLux Advanced Security Kernel" if XSM_FLASK
 	config XSM_SILO_DEFAULT
@@ -282,7 +275,7 @@  endchoice
 config LATE_HWDOM
 	bool "Dedicated hardware domain"
 	default n
-	depends on XSM && X86
+	depends on XSM_FLASK && X86
 	---help---
 	  Allows the creation of a dedicated hardware domain distinct from
 	  domain 0 that manages devices without needing access to other
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index c445c5681b..eb8d61216b 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -1,18 +1,11 @@ 
 /*
- *  Default XSM hooks - IS_PRIV and IS_PRIV_FOR checks
+ *  Default XSM hook check - enforces basic access control decisions
  *
  *  Author: Daniel De Graaf <dgdegra@tyhco.nsa.gov>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2,
  *  as published by the Free Software Foundation.
- *
- *
- *  Each XSM hook implementing an access check should have its first parameter
- *  preceded by XSM_DEFAULT_ARG (or use XSM_DEFAULT_VOID if it has no
- *  arguments). The first non-declaration statement shold be XSM_ASSERT_ACTION
- *  with the expected type of the hook, which will either define or check the
- *  value of action.
  */
 
 #include <xen/sched.h>
@@ -42,33 +35,8 @@  static inline void __xsm_action_mismatch_detected(void)
 void __xsm_action_mismatch_detected(void);
 #endif
 
-#ifdef CONFIG_XSM
-
-/* In CONFIG_XSM builds, this header file is included from xsm/dummy.c, and
- * contains static (not inline) functions compiled to the dummy XSM module.
- * There is no xsm_default_t argument available, so the value from the assertion
- * is used to initialize the variable.
- */
-#define XSM_INLINE __maybe_unused
-
-#define XSM_DEFAULT_ARG /* */
-#define XSM_DEFAULT_VOID void
-#define XSM_ASSERT_ACTION(def) xsm_default_t action = def; (void)action
-
-#else /* CONFIG_XSM */
-
-/* In !CONFIG_XSM builds, this header file is included from xsm/xsm.h, and
- * contains inline functions for each XSM hook. These functions also perform
- * compile-time checks on the xsm_default_t argument to ensure that the behavior
- * of the dummy XSM module is the same as the behavior with XSM disabled.
- */
-#define XSM_INLINE always_inline
-#define XSM_DEFAULT_ARG xsm_default_t action,
-#define XSM_DEFAULT_VOID xsm_default_t action
 #define XSM_ASSERT_ACTION(def) LINKER_BUG_ON(def != action)
 
-#endif /* CONFIG_XSM */
-
 static always_inline int xsm_default_action(
     xsm_default_t action, struct domain *src, struct domain *target)
 {
@@ -97,678 +65,3 @@  static always_inline int xsm_default_action(
         return -EPERM;
     }
 }
-
-static XSM_INLINE void xsm_security_domaininfo(struct domain *d,
-                                    struct xen_domctl_getdomaininfo *info)
-{
-    return;
-}
-
-static XSM_INLINE int xsm_domain_create(XSM_DEFAULT_ARG struct domain *d, u32 ssidref)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_getdomaininfo(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_domctl_scheduler_op(XSM_DEFAULT_ARG struct domain *d, int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_sysctl_scheduler_op(XSM_DEFAULT_ARG int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_set_target(XSM_DEFAULT_ARG struct domain *d, struct domain *e)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_domctl(XSM_DEFAULT_ARG struct domain *d, int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_OTHER);
-    switch ( cmd )
-    {
-    case XEN_DOMCTL_ioport_mapping:
-    case XEN_DOMCTL_memory_mapping:
-    case XEN_DOMCTL_bind_pt_irq:
-    case XEN_DOMCTL_unbind_pt_irq:
-        return xsm_default_action(XSM_DM_PRIV, current->domain, d);
-    case XEN_DOMCTL_getdomaininfo:
-        return xsm_default_action(XSM_XS_PRIV, current->domain, d);
-    default:
-        return xsm_default_action(XSM_PRIV, current->domain, d);
-    }
-}
-
-static XSM_INLINE int xsm_sysctl(XSM_DEFAULT_ARG int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_readconsole(XSM_DEFAULT_ARG uint32_t clear)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_alloc_security_domain(struct domain *d)
-{
-    return 0;
-}
-
-static XSM_INLINE void xsm_free_security_domain(struct domain *d)
-{
-    return;
-}
-
-static XSM_INLINE int xsm_grant_mapref(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2,
-                                                                uint32_t flags)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_grant_unmapref(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_grant_setup(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_grant_transfer(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_grant_copy(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_grant_query_size(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_memory_exchange(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_memory_adjust_reservation(XSM_DEFAULT_ARG struct domain *d1,
-                                                            struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_memory_stat_reservation(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_console_io(XSM_DEFAULT_ARG struct domain *d, int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_OTHER);
-    if ( d->is_console )
-        return xsm_default_action(XSM_HOOK, d, NULL);
-#ifdef CONFIG_VERBOSE_DEBUG
-    if ( cmd == CONSOLEIO_write )
-        return xsm_default_action(XSM_HOOK, d, NULL);
-#endif
-    return xsm_default_action(XSM_PRIV, d, NULL);
-}
-
-static XSM_INLINE int xsm_profile(XSM_DEFAULT_ARG struct domain *d, int op)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d, NULL);
-}
-
-static XSM_INLINE int xsm_kexec(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_schedop_shutdown(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_memory_pin_page(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2,
-                                          struct page_info *page)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_claim_pages(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_evtchn_unbound(XSM_DEFAULT_ARG struct domain *d, struct evtchn *chn,
-                                         domid_t id2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_evtchn_interdomain(XSM_DEFAULT_ARG struct domain *d1, struct evtchn
-                                *chan1, struct domain *d2, struct evtchn *chan2)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE void xsm_evtchn_close_post(struct evtchn *chn)
-{
-    return;
-}
-
-static XSM_INLINE int xsm_evtchn_send(XSM_DEFAULT_ARG struct domain *d, struct evtchn *chn)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, d, NULL);
-}
-
-static XSM_INLINE int xsm_evtchn_status(XSM_DEFAULT_ARG struct domain *d, struct evtchn *chn)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_evtchn_reset(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_alloc_security_evtchns(
-    struct evtchn chn[], unsigned int nr)
-{
-    return 0;
-}
-
-static XSM_INLINE void xsm_free_security_evtchns(
-    struct evtchn chn[], unsigned int nr)
-{
-    return;
-}
-
-static XSM_INLINE char *xsm_show_security_evtchn(struct domain *d, const struct evtchn *chn)
-{
-    return NULL;
-}
-
-static XSM_INLINE int xsm_init_hardware_domain(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_get_pod_target(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_set_pod_target(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_get_vnumainfo(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, current->domain, d);
-}
-
-#if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_PCI)
-static XSM_INLINE int xsm_get_device_group(XSM_DEFAULT_ARG uint32_t machine_bdf)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_assign_device(XSM_DEFAULT_ARG struct domain *d, uint32_t machine_bdf)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_deassign_device(XSM_DEFAULT_ARG struct domain *d, uint32_t machine_bdf)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-#endif /* HAS_PASSTHROUGH && HAS_PCI */
-
-#if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_DEVICE_TREE)
-static XSM_INLINE int xsm_assign_dtdevice(XSM_DEFAULT_ARG struct domain *d,
-                                          const char *dtpath)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_deassign_dtdevice(XSM_DEFAULT_ARG struct domain *d,
-                                            const char *dtpath)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-#endif /* HAS_PASSTHROUGH && HAS_DEVICE_TREE */
-
-static XSM_INLINE int xsm_resource_plug_core(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_resource_unplug_core(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_resource_plug_pci(XSM_DEFAULT_ARG uint32_t machine_bdf)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_resource_unplug_pci(XSM_DEFAULT_ARG uint32_t machine_bdf)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_resource_setup_pci(XSM_DEFAULT_ARG uint32_t machine_bdf)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_resource_setup_gsi(XSM_DEFAULT_ARG int gsi)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_resource_setup_misc(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_page_offline(XSM_DEFAULT_ARG uint32_t cmd)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_hypfs_op(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE long xsm_do_xsm_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
-{
-    return -ENOSYS;
-}
-
-#ifdef CONFIG_COMPAT
-static XSM_INLINE int xsm_do_compat_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
-{
-    return -ENOSYS;
-}
-#endif
-
-static XSM_INLINE char *xsm_show_irq_sid(int irq)
-{
-    return NULL;
-}
-
-static XSM_INLINE int xsm_map_domain_pirq(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_map_domain_irq(XSM_DEFAULT_ARG struct domain *d,
-                                         int irq, const void *data)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_unmap_domain_pirq(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_bind_pt_irq(XSM_DEFAULT_ARG struct domain *d, struct xen_domctl_bind_pt_irq *bind)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_unbind_pt_irq(XSM_DEFAULT_ARG struct domain *d, struct xen_domctl_bind_pt_irq *bind)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_unmap_domain_irq(XSM_DEFAULT_ARG struct domain *d,
-                                           int irq, const void *data)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_irq_permission(XSM_DEFAULT_ARG struct domain *d, int pirq, uint8_t allow)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_iomem_permission(XSM_DEFAULT_ARG struct domain *d, uint64_t s, uint64_t e, uint8_t allow)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_iomem_mapping(XSM_DEFAULT_ARG struct domain *d, uint64_t s, uint64_t e, uint8_t allow)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_pci_config_permission(XSM_DEFAULT_ARG struct domain *d, uint32_t machine_bdf,
-                                        uint16_t start, uint16_t end,
-                                        uint8_t access)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_add_to_physmap(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_remove_from_physmap(XSM_DEFAULT_ARG struct domain *d1, struct domain *d2)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d1, d2);
-}
-
-static XSM_INLINE int xsm_map_gmfn_foreign(XSM_DEFAULT_ARG struct domain *d, struct domain *t)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d, t);
-}
-
-static XSM_INLINE int xsm_hvm_param(XSM_DEFAULT_ARG struct domain *d, unsigned long op)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_hvm_control(XSM_DEFAULT_ARG struct domain *d, unsigned long op)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_hvm_param_altp2mhvm(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_hvm_altp2mhvm_op(XSM_DEFAULT_ARG struct domain *d, uint64_t mode, uint32_t op)
-{
-    XSM_ASSERT_ACTION(XSM_OTHER);
-
-    switch ( mode )
-    {
-    case XEN_ALTP2M_mixed:
-        return xsm_default_action(XSM_TARGET, current->domain, d);
-    case XEN_ALTP2M_external:
-        return xsm_default_action(XSM_DM_PRIV, current->domain, d);
-    case XEN_ALTP2M_limited:
-        if ( HVMOP_altp2m_vcpu_enable_notify == op )
-            return xsm_default_action(XSM_TARGET, current->domain, d);
-        return xsm_default_action(XSM_DM_PRIV, current->domain, d);
-    default:
-        return -EPERM;
-    }
-}
-
-static XSM_INLINE int xsm_vm_event_control(XSM_DEFAULT_ARG struct domain *d, int mode, int op)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-#ifdef CONFIG_MEM_ACCESS
-static XSM_INLINE int xsm_mem_access(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-#endif
-
-#ifdef CONFIG_MEM_PAGING
-static XSM_INLINE int xsm_mem_paging(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-#endif
-
-#ifdef CONFIG_MEM_SHARING
-static XSM_INLINE int xsm_mem_sharing(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-#endif
-
-static XSM_INLINE int xsm_platform_op(XSM_DEFAULT_ARG uint32_t op)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-#ifdef CONFIG_X86
-static XSM_INLINE int xsm_do_mca(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_shadow_control(XSM_DEFAULT_ARG struct domain *d, uint32_t op)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_mem_sharing_op(XSM_DEFAULT_ARG struct domain *d, struct domain *cd, int op)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, cd);
-}
-
-static XSM_INLINE int xsm_apic(XSM_DEFAULT_ARG struct domain *d, int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, d, NULL);
-}
-
-static XSM_INLINE int xsm_machine_memory_map(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
-static XSM_INLINE int xsm_domain_memory_map(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_mmu_update(XSM_DEFAULT_ARG struct domain *d, struct domain *t,
-                                     struct domain *f, uint32_t flags)
-{
-    int rc = 0;
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    if ( f != dom_io )
-        rc = xsm_default_action(action, d, f);
-    if ( evaluate_nospec(t) && !rc )
-        rc = xsm_default_action(action, d, t);
-    return rc;
-}
-
-static XSM_INLINE int xsm_mmuext_op(XSM_DEFAULT_ARG struct domain *d, struct domain *f)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d, f);
-}
-
-static XSM_INLINE int xsm_update_va_mapping(XSM_DEFAULT_ARG struct domain *d, struct domain *f, 
-                                                            l1_pgentry_t pte)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d, f);
-}
-
-static XSM_INLINE int xsm_priv_mapping(XSM_DEFAULT_ARG struct domain *d, struct domain *t)
-{
-    XSM_ASSERT_ACTION(XSM_TARGET);
-    return xsm_default_action(action, d, t);
-}
-
-static XSM_INLINE int xsm_ioport_permission(XSM_DEFAULT_ARG struct domain *d, uint32_t s, uint32_t e, uint8_t allow)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_ioport_mapping(XSM_DEFAULT_ARG struct domain *d, uint32_t s, uint32_t e, uint8_t allow)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
-static XSM_INLINE int xsm_pmu_op (XSM_DEFAULT_ARG struct domain *d, unsigned int op)
-{
-    XSM_ASSERT_ACTION(XSM_OTHER);
-    switch ( op )
-    {
-    case XENPMU_init:
-    case XENPMU_finish:
-    case XENPMU_lvtpc_set:
-    case XENPMU_flush:
-        return xsm_default_action(XSM_HOOK, d, current->domain);
-    default:
-        return xsm_default_action(XSM_PRIV, d, current->domain);
-    }
-}
-
-#endif /* CONFIG_X86 */
-
-static XSM_INLINE int xsm_dm_op(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
-
-#ifdef CONFIG_ARGO
-static XSM_INLINE int xsm_argo_enable(const struct domain *d)
-{
-    return 0;
-}
-
-static XSM_INLINE int xsm_argo_register_single_source(const struct domain *d,
-                                                      const struct domain *t)
-{
-    return 0;
-}
-
-static XSM_INLINE int xsm_argo_register_any_source(const struct domain *d)
-{
-    return 0;
-}
-
-static XSM_INLINE int xsm_argo_send(const struct domain *d,
-                                    const struct domain *t)
-{
-    return 0;
-}
-
-#endif /* CONFIG_ARGO */
-
-#include <public/version.h>
-static XSM_INLINE int xsm_xen_version (XSM_DEFAULT_ARG uint32_t op)
-{
-    XSM_ASSERT_ACTION(XSM_OTHER);
-    switch ( op )
-    {
-    case XENVER_version:
-    case XENVER_platform_parameters:
-    case XENVER_get_features:
-        /* These sub-ops ignore the permission checks and return data. */
-        block_speculation();
-        return 0;
-    case XENVER_extraversion:
-    case XENVER_compile_info:
-    case XENVER_capabilities:
-    case XENVER_changeset:
-    case XENVER_pagesize:
-    case XENVER_guest_handle:
-        /* These MUST always be accessible to any guest by default. */
-        return xsm_default_action(XSM_HOOK, current->domain, NULL);
-    default:
-        return xsm_default_action(XSM_PRIV, current->domain, NULL);
-    }
-}
-
-static XSM_INLINE int xsm_domain_resource_map(XSM_DEFAULT_ARG struct domain *d)
-{
-    XSM_ASSERT_ACTION(XSM_DM_PRIV);
-    return xsm_default_action(action, current->domain, d);
-}
diff --git a/xen/include/xsm/xsm-core.h b/xen/include/xsm/xsm-core.h
index 49b00d688c..dfe9378cb2 100644
--- a/xen/include/xsm/xsm-core.h
+++ b/xen/include/xsm/xsm-core.h
@@ -199,8 +199,6 @@  struct xsm_ops {
 
 extern void xsm_fixup_ops(struct xsm_ops *ops);
 
-#ifdef CONFIG_XSM
-
 #ifdef CONFIG_MULTIBOOT
 extern int xsm_multiboot_init(unsigned long *module_map,
                               const multiboot_info_t *mbi);
@@ -246,28 +244,4 @@  static const inline struct xsm_ops *silo_init(void)
 }
 #endif
 
-#else /* CONFIG_XSM */
-
-#ifdef CONFIG_MULTIBOOT
-static inline int xsm_multiboot_init (unsigned long *module_map,
-                                      const multiboot_info_t *mbi)
-{
-    return 0;
-}
-#endif
-
-#ifdef CONFIG_HAS_DEVICE_TREE
-static inline int xsm_dt_init(void)
-{
-    return 0;
-}
-
-static inline bool has_xsm_magic(paddr_t start)
-{
-    return false;
-}
-#endif /* CONFIG_HAS_DEVICE_TREE */
-
-#endif /* CONFIG_XSM */
-
 #endif /* __XSM_CORE_H */
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 673b818ac7..deb3a39062 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -19,545 +19,1023 @@ 
 #include <xen/sched.h>
 #include <xen/multiboot.h>
 #include <xsm/xsm-core.h>
-
-#ifdef CONFIG_XSM
+#include <xsm/dummy.h>
+#include <public/version.h>
 
 extern struct xsm_ops xsm_ops;
 
-static inline void xsm_security_domaininfo (struct domain *d,
-                                        struct xen_domctl_getdomaininfo *info)
+static inline void xsm_security_domaininfo(
+    struct domain *d,
+    struct xen_domctl_getdomaininfo *info)
 {
-    alternative_vcall(xsm_ops.security_domaininfo, d, info);
+    if ( xsm_ops.security_domaininfo )
+        alternative_vcall(xsm_ops.security_domaininfo, d, info);
 }
 
-static inline int xsm_domain_create (xsm_default_t def, struct domain *d, u32 ssidref)
+static inline int xsm_domain_create(xsm_default_t action, struct domain *d,
+                                    u32 ssidref)
 {
-    return alternative_call(xsm_ops.domain_create, d, ssidref);
+    if ( xsm_ops.domain_create )
+        return alternative_call(xsm_ops.domain_create, d, ssidref);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_getdomaininfo (xsm_default_t def, struct domain *d)
+static inline int xsm_getdomaininfo(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.getdomaininfo, d);
+    if ( xsm_ops.getdomaininfo )
+        return alternative_call(xsm_ops.getdomaininfo, d);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_domctl_scheduler_op (xsm_default_t def, struct domain *d, int cmd)
+static inline int xsm_domctl_scheduler_op(xsm_default_t action, struct domain *d,
+                                          int cmd)
 {
-    return alternative_call(xsm_ops.domctl_scheduler_op, d, cmd);
+    if ( xsm_ops.domctl_scheduler_op )
+        return alternative_call(xsm_ops.domctl_scheduler_op, d, cmd);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_sysctl_scheduler_op (xsm_default_t def, int cmd)
+static inline int xsm_sysctl_scheduler_op(xsm_default_t action, int cmd)
 {
-    return alternative_call(xsm_ops.sysctl_scheduler_op, cmd);
+    if ( xsm_ops.sysctl_scheduler_op )
+        return alternative_call(xsm_ops.sysctl_scheduler_op, cmd);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_set_target (xsm_default_t def, struct domain *d, struct domain *e)
+static inline int xsm_set_target(xsm_default_t action, struct domain *d,
+                                 struct domain *e)
 {
-    return alternative_call(xsm_ops.set_target, d, e);
+    if ( xsm_ops.set_target )
+        return alternative_call(xsm_ops.set_target, d, e);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_domctl (xsm_default_t def, struct domain *d, int cmd)
+static inline int xsm_domctl(xsm_default_t action, struct domain *d, int cmd)
 {
-    return alternative_call(xsm_ops.domctl, d, cmd);
+    if ( xsm_ops.domctl )
+        return alternative_call(xsm_ops.domctl, d, cmd);
+
+    XSM_ASSERT_ACTION(XSM_OTHER);
+    switch ( cmd )
+    {
+    case XEN_DOMCTL_ioport_mapping:
+    case XEN_DOMCTL_memory_mapping:
+    case XEN_DOMCTL_bind_pt_irq:
+    case XEN_DOMCTL_unbind_pt_irq:
+        return xsm_default_action(XSM_DM_PRIV, current->domain, d);
+    case XEN_DOMCTL_getdomaininfo:
+        return xsm_default_action(XSM_XS_PRIV, current->domain, d);
+    default:
+        return xsm_default_action(XSM_PRIV, current->domain, d);
+    }
 }
 
-static inline int xsm_sysctl (xsm_default_t def, int cmd)
+static inline int xsm_sysctl(xsm_default_t action, int cmd)
 {
-    return alternative_call(xsm_ops.sysctl, cmd);
+    if ( xsm_ops.sysctl )
+        return alternative_call(xsm_ops.sysctl, cmd);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_readconsole (xsm_default_t def, uint32_t clear)
+static inline int xsm_readconsole(xsm_default_t action, uint32_t clear)
 {
-    return alternative_call(xsm_ops.readconsole, clear);
+    if ( xsm_ops.readconsole )
+        return alternative_call(xsm_ops.readconsole, clear);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_evtchn_unbound (xsm_default_t def, struct domain *d1, struct evtchn *chn,
-                                                                    domid_t id2)
+static inline int xsm_evtchn_unbound(xsm_default_t action, struct domain *d1,
+                                     struct evtchn *chn, domid_t id2)
 {
-    return alternative_call(xsm_ops.evtchn_unbound, d1, chn, id2);
+    if ( xsm_ops.evtchn_unbound )
+        return alternative_call(xsm_ops.evtchn_unbound, d1, chn, id2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, current->domain, d1);
 }
 
-static inline int xsm_evtchn_interdomain (xsm_default_t def, struct domain *d1,
-                struct evtchn *chan1, struct domain *d2, struct evtchn *chan2)
+static inline int xsm_evtchn_interdomain(xsm_default_t action,
+                                         struct domain *d1,
+                                         struct evtchn *chan1,
+                                         struct domain *d2,
+                                         struct evtchn *chan2)
 {
-    return alternative_call(xsm_ops.evtchn_interdomain, d1, chan1, d2, chan2);
+    if ( xsm_ops.evtchn_interdomain )
+        return alternative_call(xsm_ops.evtchn_interdomain, d1, chan1, d2,
+                                chan2);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline void xsm_evtchn_close_post (struct evtchn *chn)
+static inline void xsm_evtchn_close_post(struct evtchn *chn)
 {
-    alternative_vcall(xsm_ops.evtchn_close_post, chn);
+    if ( xsm_ops.evtchn_close_post )
+        alternative_vcall(xsm_ops.evtchn_close_post, chn);
 }
 
-static inline int xsm_evtchn_send (xsm_default_t def, struct domain *d, struct evtchn *chn)
+static inline int xsm_evtchn_send(xsm_default_t action, struct domain *d,
+                                  struct evtchn *chn)
 {
-    return alternative_call(xsm_ops.evtchn_send, d, chn);
+    if ( xsm_ops.evtchn_send )
+        return alternative_call(xsm_ops.evtchn_send, d, chn);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d, NULL);
 }
 
-static inline int xsm_evtchn_status (xsm_default_t def, struct domain *d, struct evtchn *chn)
+static inline int xsm_evtchn_status(xsm_default_t action, struct domain *d,
+                                    struct evtchn *chn)
 {
-    return alternative_call(xsm_ops.evtchn_status, d, chn);
+    if ( xsm_ops.evtchn_status )
+        return alternative_call(xsm_ops.evtchn_status, d, chn);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_evtchn_reset (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_evtchn_reset(xsm_default_t action, struct domain *d1,
+                                   struct domain *d2)
 {
-    return alternative_call(xsm_ops.evtchn_reset, d1, d2);
+    if ( xsm_ops.evtchn_reset )
+        return alternative_call(xsm_ops.evtchn_reset, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_grant_mapref (xsm_default_t def, struct domain *d1, struct domain *d2,
-                                                                uint32_t flags)
+static inline int xsm_grant_mapref(xsm_default_t action, struct domain *d1,
+                                   struct domain *d2, uint32_t flags)
 {
-    return alternative_call(xsm_ops.grant_mapref, d1, d2, flags);
+    if ( xsm_ops.grant_mapref )
+        return alternative_call(xsm_ops.grant_mapref, d1, d2, flags);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_grant_unmapref (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_grant_unmapref(xsm_default_t action, struct domain *d1,
+                                     struct domain *d2)
 {
-    return alternative_call(xsm_ops.grant_unmapref, d1, d2);
+    if ( xsm_ops.grant_unmapref )
+        return alternative_call(xsm_ops.grant_unmapref, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_grant_setup (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_grant_setup(xsm_default_t action, struct domain *d1,
+                                  struct domain *d2)
 {
-    return alternative_call(xsm_ops.grant_setup, d1, d2);
+    if ( xsm_ops.grant_setup )
+        return alternative_call(xsm_ops.grant_setup, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_grant_transfer (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_grant_transfer(xsm_default_t action, struct domain *d1,
+                                     struct domain *d2)
 {
-    return alternative_call(xsm_ops.grant_transfer, d1, d2);
+    if ( xsm_ops.grant_transfer )
+        return alternative_call(xsm_ops.grant_transfer, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_grant_copy (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_grant_copy(xsm_default_t action, struct domain *d1,
+                                 struct domain *d2)
 {
-    return alternative_call(xsm_ops.grant_copy, d1, d2);
+    if ( xsm_ops.grant_copy )
+        return alternative_call(xsm_ops.grant_copy, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_grant_query_size (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_grant_query_size(xsm_default_t action, struct domain *d1,
+                                       struct domain *d2)
 {
-    return alternative_call(xsm_ops.grant_query_size, d1, d2);
+    if ( xsm_ops.grant_query_size )
+        return alternative_call(xsm_ops.grant_query_size, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_alloc_security_domain (struct domain *d)
+static inline int xsm_alloc_security_domain(struct domain *d)
 {
-    return alternative_call(xsm_ops.alloc_security_domain, d);
+    if ( xsm_ops.alloc_security_domain )
+        return alternative_call(xsm_ops.alloc_security_domain, d);
+
+    return 0;
 }
 
-static inline void xsm_free_security_domain (struct domain *d)
+static inline void xsm_free_security_domain(struct domain *d)
 {
-    alternative_vcall(xsm_ops.free_security_domain, d);
+    if ( xsm_ops.free_security_domain )
+        alternative_vcall(xsm_ops.free_security_domain, d);
 }
 
-static inline int xsm_alloc_security_evtchns(
-    struct evtchn chn[], unsigned int nr)
+static inline int xsm_alloc_security_evtchns(struct evtchn chn[],
+                                             unsigned int nr)
 {
-    return alternative_call(xsm_ops.alloc_security_evtchns, chn, nr);
+    if ( xsm_ops.alloc_security_evtchns )
+        return alternative_call(xsm_ops.alloc_security_evtchns, chn, nr);
+
+    return 0;
 }
 
-static inline void xsm_free_security_evtchns(
-    struct evtchn chn[], unsigned int nr)
+static inline void xsm_free_security_evtchns(struct evtchn chn[],
+                                             unsigned int nr)
 {
-    alternative_vcall(xsm_ops.free_security_evtchns, chn, nr);
+    if ( xsm_ops.free_security_evtchns )
+        alternative_vcall(xsm_ops.free_security_evtchns, chn, nr);
 }
 
-static inline char *xsm_show_security_evtchn (struct domain *d, const struct evtchn *chn)
+static inline char *xsm_show_security_evtchn(struct domain *d,
+                                             const struct evtchn *chn)
 {
-    return alternative_call(xsm_ops.show_security_evtchn, d, chn);
+    if ( xsm_ops.show_security_evtchn )
+        return alternative_call(xsm_ops.show_security_evtchn, d, chn);
+
+    return NULL;
 }
 
-static inline int xsm_init_hardware_domain (xsm_default_t def, struct domain *d)
+static inline int xsm_init_hardware_domain(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.init_hardware_domain, d);
+    if ( xsm_ops.init_hardware_domain )
+        return alternative_call(xsm_ops.init_hardware_domain, d);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_get_pod_target (xsm_default_t def, struct domain *d)
+static inline int xsm_get_pod_target(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.get_pod_target, d);
+    if ( xsm_ops.get_pod_target )
+        return alternative_call(xsm_ops.get_pod_target, d);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_set_pod_target (xsm_default_t def, struct domain *d)
+static inline int xsm_set_pod_target(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.set_pod_target, d);
+    if ( xsm_ops.set_pod_target )
+        return alternative_call(xsm_ops.set_pod_target, d);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_memory_exchange (xsm_default_t def, struct domain *d)
+static inline int xsm_memory_exchange(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.memory_exchange, d);
+    if ( xsm_ops.memory_exchange )
+        return alternative_call(xsm_ops.memory_exchange, d);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_memory_adjust_reservation (xsm_default_t def, struct domain *d1, struct
-                                                                    domain *d2)
+static inline int xsm_memory_adjust_reservation(xsm_default_t action,
+                                                struct domain *d1,
+                                                struct domain *d2)
 {
-    return alternative_call(xsm_ops.memory_adjust_reservation, d1, d2);
+    if ( xsm_ops.memory_adjust_reservation )
+        return alternative_call(xsm_ops.memory_adjust_reservation, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_memory_stat_reservation (xsm_default_t def, struct domain *d1,
-                                                            struct domain *d2)
+static inline int xsm_memory_stat_reservation(xsm_default_t action,
+                                              struct domain *d1,
+                                              struct domain *d2)
 {
-    return alternative_call(xsm_ops.memory_stat_reservation, d1, d2);
+    if ( xsm_ops.memory_stat_reservation )
+        return alternative_call(xsm_ops.memory_stat_reservation, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_memory_pin_page(xsm_default_t def, struct domain *d1, struct domain *d2,
-                                      struct page_info *page)
+static inline int xsm_memory_pin_page(xsm_default_t action, struct domain *d1,
+                                      struct domain *d2, struct page_info *page)
 {
-    return alternative_call(xsm_ops.memory_pin_page, d1, d2, page);
+    if ( xsm_ops.memory_pin_page )
+        return alternative_call(xsm_ops.memory_pin_page, d1, d2, page);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_add_to_physmap(xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_add_to_physmap(xsm_default_t action, struct domain *d1,
+                                     struct domain *d2)
 {
-    return alternative_call(xsm_ops.add_to_physmap, d1, d2);
+    if ( xsm_ops.add_to_physmap )
+        return alternative_call(xsm_ops.add_to_physmap, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_remove_from_physmap(xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_remove_from_physmap(xsm_default_t action, struct domain *d1,
+                                          struct domain *d2)
 {
-    return alternative_call(xsm_ops.remove_from_physmap, d1, d2);
+    if ( xsm_ops.remove_from_physmap )
+        return alternative_call(xsm_ops.remove_from_physmap, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline int xsm_map_gmfn_foreign (xsm_default_t def, struct domain *d, struct domain *t)
+static inline int xsm_map_gmfn_foreign(xsm_default_t action, struct domain *d,
+                                       struct domain *t)
 {
-    return alternative_call(xsm_ops.map_gmfn_foreign, d, t);
+    if ( xsm_ops.map_gmfn_foreign )
+        return alternative_call(xsm_ops.map_gmfn_foreign, d, t);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d, t);
 }
 
-static inline int xsm_claim_pages(xsm_default_t def, struct domain *d)
+static inline int xsm_claim_pages(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.claim_pages, d);
+    if ( xsm_ops.claim_pages )
+        return alternative_call(xsm_ops.claim_pages, d);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_console_io (xsm_default_t def, struct domain *d, int cmd)
+static inline int xsm_console_io(xsm_default_t action, struct domain *d, int cmd)
 {
-    return alternative_call(xsm_ops.console_io, d, cmd);
+    if ( xsm_ops.console_io )
+        return alternative_call(xsm_ops.console_io, d, cmd);
+
+    XSM_ASSERT_ACTION(XSM_OTHER);
+    if ( d->is_console )
+        return xsm_default_action(XSM_HOOK, d, NULL);
+#ifdef CONFIG_VERBOSE_DEBUG
+    if ( cmd == CONSOLEIO_write )
+        return xsm_default_action(XSM_HOOK, d, NULL);
+#endif
+    return xsm_default_action(XSM_PRIV, d, NULL);
 }
 
-static inline int xsm_profile (xsm_default_t def, struct domain *d, int op)
+static inline int xsm_profile(xsm_default_t action, struct domain *d, int op)
 {
-    return alternative_call(xsm_ops.profile, d, op);
+    if ( xsm_ops.profile )
+        return alternative_call(xsm_ops.profile, d, op);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, d, NULL);
 }
 
-static inline int xsm_kexec (xsm_default_t def)
+static inline int xsm_kexec (xsm_default_t action)
 {
-    return alternative_call(xsm_ops.kexec);
+    if ( xsm_ops.kexec )
+        return alternative_call(xsm_ops.kexec);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_schedop_shutdown (xsm_default_t def, struct domain *d1, struct domain *d2)
+static inline int xsm_schedop_shutdown(xsm_default_t action, struct domain *d1,
+                                       struct domain *d2)
 {
-    return alternative_call(xsm_ops.schedop_shutdown, d1, d2);
+    if ( xsm_ops.schedop_shutdown )
+        return alternative_call(xsm_ops.schedop_shutdown, d1, d2);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, d1, d2);
 }
 
-static inline char *xsm_show_irq_sid (int irq)
+static inline char *xsm_show_irq_sid(int irq)
 {
-    return alternative_call(xsm_ops.show_irq_sid, irq);
+    if ( xsm_ops.show_irq_sid )
+        return alternative_call(xsm_ops.show_irq_sid, irq);
+
+    return NULL;
 }
 
-static inline int xsm_map_domain_pirq (xsm_default_t def, struct domain *d)
+static inline int xsm_map_domain_pirq(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.map_domain_pirq, d);
+    if ( xsm_ops.map_domain_pirq )
+        return alternative_call(xsm_ops.map_domain_pirq, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_map_domain_irq (xsm_default_t def, struct domain *d, int irq, void *data)
+static inline int xsm_map_domain_irq(xsm_default_t action, struct domain *d,
+                                     int irq, void *data)
 {
-    return alternative_call(xsm_ops.map_domain_irq, d, irq, data);
+    if ( xsm_ops.map_domain_irq )
+        return alternative_call(xsm_ops.map_domain_irq, d, irq, data);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_unmap_domain_pirq (xsm_default_t def, struct domain *d)
+static inline int xsm_unmap_domain_pirq(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.unmap_domain_pirq, d);
+    if ( xsm_ops.unmap_domain_pirq )
+        return alternative_call(xsm_ops.unmap_domain_pirq, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_unmap_domain_irq (xsm_default_t def, struct domain *d, int irq, void *data)
+static inline int xsm_unmap_domain_irq(xsm_default_t action, struct domain *d,
+                                       int irq, void *data)
 {
-    return alternative_call(xsm_ops.unmap_domain_irq, d, irq, data);
+    if ( xsm_ops.unmap_domain_irq )
+        return alternative_call(xsm_ops.unmap_domain_irq, d, irq, data);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_bind_pt_irq(xsm_default_t def, struct domain *d,
+static inline int xsm_bind_pt_irq(xsm_default_t action, struct domain *d,
                                   struct xen_domctl_bind_pt_irq *bind)
 {
-    return alternative_call(xsm_ops.bind_pt_irq, d, bind);
+    if ( xsm_ops.bind_pt_irq )
+        return alternative_call(xsm_ops.bind_pt_irq, d, bind);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_unbind_pt_irq(xsm_default_t def, struct domain *d,
+static inline int xsm_unbind_pt_irq(xsm_default_t action, struct domain *d,
                                     struct xen_domctl_bind_pt_irq *bind)
 {
-    return alternative_call(xsm_ops.unbind_pt_irq, d, bind);
+    if ( xsm_ops.unbind_pt_irq )
+        return alternative_call(xsm_ops.unbind_pt_irq, d, bind);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_irq_permission (xsm_default_t def, struct domain *d, int pirq, uint8_t allow)
+static inline int xsm_irq_permission(xsm_default_t action, struct domain *d,
+                                     int pirq, uint8_t allow)
 {
-    return alternative_call(xsm_ops.irq_permission, d, pirq, allow);
+    if ( xsm_ops.irq_permission )
+        return alternative_call(xsm_ops.irq_permission, d, pirq, allow);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_iomem_permission (xsm_default_t def, struct domain *d, uint64_t s, uint64_t e, uint8_t allow)
+static inline int xsm_iomem_permission(xsm_default_t action, struct domain *d,
+                                       uint64_t s, uint64_t e, uint8_t allow)
 {
-    return alternative_call(xsm_ops.iomem_permission, d, s, e, allow);
+    if ( xsm_ops.iomem_permission )
+        return alternative_call(xsm_ops.iomem_permission, d, s, e, allow);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_iomem_mapping (xsm_default_t def, struct domain *d, uint64_t s, uint64_t e, uint8_t allow)
+static inline int xsm_iomem_mapping(xsm_default_t action, struct domain *d,
+                                    uint64_t s, uint64_t e, uint8_t allow)
 {
-    return alternative_call(xsm_ops.iomem_mapping, d, s, e, allow);
+    if ( xsm_ops.iomem_mapping )
+        return alternative_call(xsm_ops.iomem_mapping, d, s, e, allow);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_pci_config_permission (xsm_default_t def, struct domain *d, uint32_t machine_bdf, uint16_t start, uint16_t end, uint8_t access)
+static inline int xsm_pci_config_permission(xsm_default_t action,
+                                            struct domain *d,
+                                            uint32_t machine_bdf,
+                                            uint16_t start,
+                                            uint16_t end,
+                                            uint8_t access)
 {
-    return alternative_call(xsm_ops.pci_config_permission, d, machine_bdf, start, end, access);
+    if ( xsm_ops.pci_config_permission )
+        return alternative_call(xsm_ops.pci_config_permission, d, machine_bdf, start, end, access);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
 #if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_PCI)
-static inline int xsm_get_device_group(xsm_default_t def, uint32_t machine_bdf)
+static inline int xsm_get_device_group(xsm_default_t action, uint32_t machine_bdf)
 {
-    return alternative_call(xsm_ops.get_device_group, machine_bdf);
+    if ( xsm_ops.get_device_group )
+        return alternative_call(xsm_ops.get_device_group, machine_bdf);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_assign_device(xsm_default_t def, struct domain *d, uint32_t machine_bdf)
+static inline int xsm_assign_device(xsm_default_t action, struct domain *d,
+                                    uint32_t machine_bdf)
 {
-    return alternative_call(xsm_ops.assign_device, d, machine_bdf);
+    if ( xsm_ops.assign_device )
+        return alternative_call(xsm_ops.assign_device, d, machine_bdf);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_deassign_device(xsm_default_t def, struct domain *d, uint32_t machine_bdf)
+static inline int xsm_deassign_device(xsm_default_t action, struct domain *d,
+                                      uint32_t machine_bdf)
 {
-    return alternative_call(xsm_ops.deassign_device, d, machine_bdf);
+    if ( xsm_ops.deassign_device )
+        return alternative_call(xsm_ops.deassign_device, d, machine_bdf);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 #endif /* HAS_PASSTHROUGH && HAS_PCI) */
 
 #if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_DEVICE_TREE)
-static inline int xsm_assign_dtdevice(xsm_default_t def, struct domain *d,
+static inline int xsm_assign_dtdevice(xsm_default_t action, struct domain *d,
                                       const char *dtpath)
 {
-    return alternative_call(xsm_ops.assign_dtdevice, d, dtpath);
+    if ( xsm_ops.assign_dtdevice )
+        return alternative_call(xsm_ops.assign_dtdevice, d, dtpath);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_deassign_dtdevice(xsm_default_t def, struct domain *d,
+static inline int xsm_deassign_dtdevice(xsm_default_t action, struct domain *d,
                                         const char *dtpath)
 {
-    return alternative_call(xsm_ops.deassign_dtdevice, d, dtpath);
+    if ( xsm_ops.deassign_dtdevice )
+        return alternative_call(xsm_ops.deassign_dtdevice, d, dtpath);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
 #endif /* HAS_PASSTHROUGH && HAS_DEVICE_TREE */
 
-static inline int xsm_resource_plug_pci (xsm_default_t def, uint32_t machine_bdf)
+static inline int xsm_resource_plug_pci(xsm_default_t action, uint32_t machine_bdf)
 {
-    return alternative_call(xsm_ops.resource_plug_pci, machine_bdf);
+    if ( xsm_ops.resource_plug_pci )
+        return alternative_call(xsm_ops.resource_plug_pci, machine_bdf);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_resource_unplug_pci (xsm_default_t def, uint32_t machine_bdf)
+static inline int xsm_resource_unplug_pci(xsm_default_t action,
+                                           uint32_t machine_bdf)
 {
-    return alternative_call(xsm_ops.resource_unplug_pci, machine_bdf);
+    if ( xsm_ops.resource_unplug_pci )
+        return alternative_call(xsm_ops.resource_unplug_pci, machine_bdf);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_resource_plug_core (xsm_default_t def)
+static inline int xsm_resource_plug_core(xsm_default_t action)
 {
-    return alternative_call(xsm_ops.resource_plug_core);
+    if ( xsm_ops.resource_plug_core )
+        return alternative_call(xsm_ops.resource_plug_core);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_resource_unplug_core (xsm_default_t def)
+static inline int xsm_resource_unplug_core(xsm_default_t action)
 {
-    return alternative_call(xsm_ops.resource_unplug_core);
+    if ( xsm_ops.resource_unplug_core )
+        return alternative_call(xsm_ops.resource_unplug_core);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_resource_setup_pci (xsm_default_t def, uint32_t machine_bdf)
+static inline int xsm_resource_setup_pci(xsm_default_t action,
+                                         uint32_t machine_bdf)
 {
-    return alternative_call(xsm_ops.resource_setup_pci, machine_bdf);
+    if ( xsm_ops.resource_setup_pci )
+        return alternative_call(xsm_ops.resource_setup_pci, machine_bdf);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_resource_setup_gsi (xsm_default_t def, int gsi)
+static inline int xsm_resource_setup_gsi(xsm_default_t action, int gsi)
 {
-    return alternative_call(xsm_ops.resource_setup_gsi, gsi);
+    if ( xsm_ops.resource_setup_gsi )
+        return alternative_call(xsm_ops.resource_setup_gsi, gsi);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_resource_setup_misc (xsm_default_t def)
+static inline int xsm_resource_setup_misc (xsm_default_t action)
 {
-    return alternative_call(xsm_ops.resource_setup_misc);
+    if ( xsm_ops.resource_setup_misc )
+        return alternative_call(xsm_ops.resource_setup_misc);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_page_offline(xsm_default_t def, uint32_t cmd)
+static inline int xsm_page_offline(xsm_default_t action, uint32_t cmd)
 {
-    return alternative_call(xsm_ops.page_offline, cmd);
+    if ( xsm_ops.page_offline )
+        return alternative_call(xsm_ops.page_offline, cmd);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_hypfs_op(xsm_default_t def)
+static inline int xsm_hypfs_op(xsm_default_t action)
 {
-    return alternative_call(xsm_ops.hypfs_op);
+    if ( xsm_ops.hypfs_op )
+        return alternative_call(xsm_ops.hypfs_op);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline long xsm_do_xsm_op (XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
+static inline long xsm_do_xsm_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
 {
-    return xsm_ops.do_xsm_op(op);
+    if ( xsm_ops.do_xsm_op )
+        return xsm_ops.do_xsm_op(op);
+
+    return -ENOSYS;
 }
 
 #ifdef CONFIG_COMPAT
-static inline int xsm_do_compat_op (XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
+static inline int xsm_do_compat_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
 {
-    return xsm_ops.do_compat_op(op);
+    if ( xsm_ops.do_compat_op )
+        return xsm_ops.do_compat_op(op);
+
+    return -ENOSYS;
 }
 #endif
 
-static inline int xsm_hvm_param (xsm_default_t def, struct domain *d, unsigned long op)
+static inline int xsm_hvm_param(xsm_default_t action, struct domain *d,
+                                unsigned long op)
 {
-    return alternative_call(xsm_ops.hvm_param, d, op);
+    if ( xsm_ops.hvm_param )
+        return alternative_call(xsm_ops.hvm_param, d, op);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_hvm_control(xsm_default_t def, struct domain *d, unsigned long op)
+static inline int xsm_hvm_control(xsm_default_t action, struct domain *d,
+                                  unsigned long op)
 {
-    return alternative_call(xsm_ops.hvm_control, d, op);
+    if ( xsm_ops.hvm_control )
+        return alternative_call(xsm_ops.hvm_control, d, op);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_hvm_param_altp2mhvm (xsm_default_t def, struct domain *d)
+static inline int xsm_hvm_param_altp2mhvm(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.hvm_param_altp2mhvm, d);
+    if ( xsm_ops.hvm_param_altp2mhvm )
+        return alternative_call(xsm_ops.hvm_param_altp2mhvm, d);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_hvm_altp2mhvm_op (xsm_default_t def, struct domain *d, uint64_t mode, uint32_t op)
+static inline int xsm_hvm_altp2mhvm_op(xsm_default_t action, struct domain *d,
+                                       uint64_t mode, uint32_t op)
 {
-    return alternative_call(xsm_ops.hvm_altp2mhvm_op, d, mode, op);
+    if ( xsm_ops.hvm_altp2mhvm_op )
+        return alternative_call(xsm_ops.hvm_altp2mhvm_op, d, mode, op);
+
+    XSM_ASSERT_ACTION(XSM_OTHER);
+
+    switch ( mode )
+    {
+    case XEN_ALTP2M_mixed:
+        return xsm_default_action(XSM_TARGET, current->domain, d);
+    case XEN_ALTP2M_external:
+        return xsm_default_action(XSM_DM_PRIV, current->domain, d);
+    case XEN_ALTP2M_limited:
+        if ( HVMOP_altp2m_vcpu_enable_notify == op )
+            return xsm_default_action(XSM_TARGET, current->domain, d);
+        return xsm_default_action(XSM_DM_PRIV, current->domain, d);
+    default:
+        return -EPERM;
+    }
 }
 
-static inline int xsm_get_vnumainfo (xsm_default_t def, struct domain *d)
+static inline int xsm_get_vnumainfo(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.get_vnumainfo, d);
+    if ( xsm_ops.get_vnumainfo )
+        return alternative_call(xsm_ops.get_vnumainfo, d);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_vm_event_control (xsm_default_t def, struct domain *d, int mode, int op)
+static inline int xsm_vm_event_control(xsm_default_t action, struct domain *d,
+                                       int mode, int op)
 {
-    return alternative_call(xsm_ops.vm_event_control, d, mode, op);
+    if ( xsm_ops.vm_event_control )
+        return alternative_call(xsm_ops.vm_event_control, d, mode, op);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
 #ifdef CONFIG_MEM_ACCESS
-static inline int xsm_mem_access (xsm_default_t def, struct domain *d)
+static inline int xsm_mem_access(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.mem_access, d);
+    if ( xsm_ops.mem_access )
+        return alternative_call(xsm_ops.mem_access, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 #endif
 
 #ifdef CONFIG_MEM_PAGING
-static inline int xsm_mem_paging (xsm_default_t def, struct domain *d)
+static inline int xsm_mem_paging(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.mem_paging, d);
+    if ( xsm_ops.mem_paging )
+        return alternative_call(xsm_ops.mem_paging, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 #endif
 
 #ifdef CONFIG_MEM_SHARING
-static inline int xsm_mem_sharing (xsm_default_t def, struct domain *d)
+static inline int xsm_mem_sharing(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.mem_sharing, d);
+    if ( xsm_ops.mem_sharing )
+        return alternative_call(xsm_ops.mem_sharing, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 #endif
 
-static inline int xsm_platform_op (xsm_default_t def, uint32_t op)
+static inline int xsm_platform_op(xsm_default_t action, uint32_t op)
 {
-    return alternative_call(xsm_ops.platform_op, op);
+    if ( xsm_ops.platform_op )
+        return alternative_call(xsm_ops.platform_op, op);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
 #ifdef CONFIG_X86
-static inline int xsm_do_mca(xsm_default_t def)
+static inline int xsm_do_mca(xsm_default_t action)
 {
-    return alternative_call(xsm_ops.do_mca);
+    if ( xsm_ops.do_mca )
+        return alternative_call(xsm_ops.do_mca);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_shadow_control (xsm_default_t def, struct domain *d, uint32_t op)
+static inline int xsm_shadow_control(xsm_default_t action, struct domain *d,
+                                     uint32_t op)
 {
-    return alternative_call(xsm_ops.shadow_control, d, op);
+    if ( xsm_ops.shadow_control )
+        return alternative_call(xsm_ops.shadow_control, d, op);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_mem_sharing_op (xsm_default_t def, struct domain *d, struct domain *cd, int op)
+static inline int xsm_mem_sharing_op(xsm_default_t action, struct domain *d,
+                                     struct domain *cd, int op)
 {
-    return alternative_call(xsm_ops.mem_sharing_op, d, cd, op);
+    if ( xsm_ops.mem_sharing_op )
+        return alternative_call(xsm_ops.mem_sharing_op, d, cd, op);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, cd);
 }
 
-static inline int xsm_apic (xsm_default_t def, struct domain *d, int cmd)
+static inline int xsm_apic(xsm_default_t action, struct domain *d, int cmd)
 {
-    return alternative_call(xsm_ops.apic, d, cmd);
+    if ( xsm_ops.apic )
+        return alternative_call(xsm_ops.apic, d, cmd);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, d, NULL);
 }
 
-static inline int xsm_memtype (xsm_default_t def, uint32_t access)
+/* No longer called */
+static inline int xsm_memtype(xsm_default_t action, uint32_t access)
 {
-    return alternative_call(xsm_ops.memtype, access);
+    if ( xsm_ops.memtype )
+        return alternative_call(xsm_ops.memtype, access);
 }
 
-static inline int xsm_machine_memory_map(xsm_default_t def)
+static inline int xsm_machine_memory_map(xsm_default_t action)
 {
-    return alternative_call(xsm_ops.machine_memory_map);
+    if ( xsm_ops.machine_memory_map )
+        return alternative_call(xsm_ops.machine_memory_map);
+
+    XSM_ASSERT_ACTION(XSM_PRIV);
+    return xsm_default_action(action, current->domain, NULL);
 }
 
-static inline int xsm_domain_memory_map(xsm_default_t def, struct domain *d)
+static inline int xsm_domain_memory_map(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.domain_memory_map, d);
+    if ( xsm_ops.domain_memory_map )
+        return alternative_call(xsm_ops.domain_memory_map, d);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_mmu_update (xsm_default_t def, struct domain *d, struct domain *t,
-                                  struct domain *f, uint32_t flags)
+static inline int xsm_mmu_update(xsm_default_t action, struct domain *d,
+                                 struct domain *t, struct domain *f,
+                                 uint32_t flags)
 {
-    return alternative_call(xsm_ops.mmu_update, d, t, f, flags);
+    int rc = 0;
+
+    if ( xsm_ops.mmu_update )
+        return alternative_call(xsm_ops.mmu_update, d, t, f, flags);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    if ( f != dom_io )
+        rc = xsm_default_action(action, d, f);
+    if ( evaluate_nospec(t) && !rc )
+        rc = xsm_default_action(action, d, t);
+    return rc;
 }
 
-static inline int xsm_mmuext_op (xsm_default_t def, struct domain *d, struct domain *f)
+static inline int xsm_mmuext_op(xsm_default_t action, struct domain *d,
+                                struct domain *f)
 {
-    return alternative_call(xsm_ops.mmuext_op, d, f);
+    if ( xsm_ops.mmuext_op )
+        return alternative_call(xsm_ops.mmuext_op, d, f);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d, f);
 }
 
-static inline int xsm_update_va_mapping(xsm_default_t def, struct domain *d, struct domain *f,
-                                                            l1_pgentry_t pte)
+static inline int xsm_update_va_mapping(xsm_default_t action, struct domain *d,
+                                        struct domain *f, l1_pgentry_t pte)
 {
-    return xsm_ops.update_va_mapping(d, f, pte);
+    if ( xsm_ops.update_va_mapping )
+        return xsm_ops.update_va_mapping(d, f, pte);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d, f);
 }
 
-static inline int xsm_priv_mapping(xsm_default_t def, struct domain *d, struct domain *t)
+static inline int xsm_priv_mapping(xsm_default_t action, struct domain *d,
+                                   struct domain *t)
 {
-    return alternative_call(xsm_ops.priv_mapping, d, t);
+    if ( xsm_ops.priv_mapping )
+        return alternative_call(xsm_ops.priv_mapping, d, t);
+
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d, t);
 }
 
-static inline int xsm_ioport_permission (xsm_default_t def, struct domain *d, uint32_t s, uint32_t e, uint8_t allow)
+static inline int xsm_ioport_permission(xsm_default_t action, struct domain *d,
+                                        uint32_t s, uint32_t e, uint8_t allow)
 {
-    return alternative_call(xsm_ops.ioport_permission, d, s, e, allow);
+    if ( xsm_ops.ioport_permission )
+        return alternative_call(xsm_ops.ioport_permission, d, s, e, allow);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_ioport_mapping (xsm_default_t def, struct domain *d, uint32_t s, uint32_t e, uint8_t allow)
+static inline int xsm_ioport_mapping(xsm_default_t action, struct domain *d,
+                                     uint32_t s, uint32_t e, uint8_t allow)
 {
-    return alternative_call(xsm_ops.ioport_mapping, d, s, e, allow);
+    if ( xsm_ops.ioport_mapping )
+        return alternative_call(xsm_ops.ioport_mapping, d, s, e, allow);
+
+    XSM_ASSERT_ACTION(XSM_HOOK);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_pmu_op (xsm_default_t def, struct domain *d, unsigned int op)
+static inline int xsm_pmu_op(xsm_default_t action, struct domain *d,
+                             unsigned int op)
 {
-    return alternative_call(xsm_ops.pmu_op, d, op);
+    if ( xsm_ops.pmu_op )
+        return alternative_call(xsm_ops.pmu_op, d, op);
+
+    XSM_ASSERT_ACTION(XSM_OTHER);
+    switch ( op )
+    {
+    case XENPMU_init:
+    case XENPMU_finish:
+    case XENPMU_lvtpc_set:
+    case XENPMU_flush:
+        return xsm_default_action(XSM_HOOK, d, current->domain);
+    default:
+        return xsm_default_action(XSM_PRIV, d, current->domain);
+    }
 }
 
 #endif /* CONFIG_X86 */
 
-static inline int xsm_dm_op(xsm_default_t def, struct domain *d)
+static inline int xsm_dm_op(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.dm_op, d);
+    if ( xsm_ops.dm_op )
+        return alternative_call(xsm_ops.dm_op, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
-static inline int xsm_xen_version (xsm_default_t def, uint32_t op)
+static inline int xsm_xen_version(xsm_default_t action, uint32_t op)
 {
-    return alternative_call(xsm_ops.xen_version, op);
+    if ( xsm_ops.xen_version )
+        return alternative_call(xsm_ops.xen_version, op);
+
+    XSM_ASSERT_ACTION(XSM_OTHER);
+    switch ( op )
+    {
+    case XENVER_version:
+    case XENVER_platform_parameters:
+    case XENVER_get_features:
+        /* These sub-ops ignore the permission checks and return data. */
+        block_speculation();
+        return 0;
+    case XENVER_extraversion:
+    case XENVER_compile_info:
+    case XENVER_capabilities:
+    case XENVER_changeset:
+    case XENVER_pagesize:
+    case XENVER_guest_handle:
+        /* These MUST always be accessible to any guest by default. */
+        return xsm_default_action(XSM_HOOK, current->domain, NULL);
+    default:
+        return xsm_default_action(XSM_PRIV, current->domain, NULL);
+    }
 }
 
-static inline int xsm_domain_resource_map(xsm_default_t def, struct domain *d)
+static inline int xsm_domain_resource_map(xsm_default_t action, struct domain *d)
 {
-    return alternative_call(xsm_ops.domain_resource_map, d);
+    if ( xsm_ops.domain_resource_map )
+        return alternative_call(xsm_ops.domain_resource_map, d);
+
+    XSM_ASSERT_ACTION(XSM_DM_PRIV);
+    return xsm_default_action(action, current->domain, d);
 }
 
 #ifdef CONFIG_ARGO
 static inline int xsm_argo_enable(const struct domain *d)
 {
-    return alternative_call(xsm_ops.argo_enable, d);
+    if ( xsm_ops.argo_enable )
+        return alternative_call(xsm_ops.argo_enable, d);
+
+    return 0;
 }
 
 static inline int xsm_argo_register_single_source(const struct domain *d,
                                                   const struct domain *t)
 {
-    return alternative_call(xsm_ops.argo_register_single_source, d, t);
+    if ( xsm_ops.argo_register_single_source )
+        return alternative_call(xsm_ops.argo_register_single_source, d, t);
+
+    return 0;
 }
 
 static inline int xsm_argo_register_any_source(const struct domain *d)
 {
-    return alternative_call(xsm_ops.argo_register_any_source, d);
+    if ( xsm_ops.argo_register_any_source )
+        return alternative_call(xsm_ops.argo_register_any_source, d);
+
+    return 0;
 }
 
 static inline int xsm_argo_send(const struct domain *d, const struct domain *t)
 {
-    return alternative_call(xsm_ops.argo_send, d, t);
+    if ( xsm_ops.argo_send )
+        return alternative_call(xsm_ops.argo_send, d, t);
+
+    return 0;
 }
 
 #endif /* CONFIG_ARGO */
 
-#else /* CONFIG_XSM */
-
-#include <xsm/dummy.h>
-
-#endif /* CONFIG_XSM */
-
 #endif /* __XSM_H */
diff --git a/xen/xsm/Makefile b/xen/xsm/Makefile
index cf0a728f1c..ab1fb74edc 100644
--- a/xen/xsm/Makefile
+++ b/xen/xsm/Makefile
@@ -1,6 +1,5 @@ 
 obj-y += xsm_core.o
-obj-$(CONFIG_XSM) += xsm_policy.o
-obj-$(CONFIG_XSM) += dummy.o
+obj-y += xsm_policy.o
 obj-$(CONFIG_XSM_SILO) += silo.o
 
 obj-$(CONFIG_XSM_FLASK) += flask/
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
deleted file mode 100644
index b848580eaa..0000000000
--- a/xen/xsm/dummy.c
+++ /dev/null
@@ -1,157 +0,0 @@ 
-/*
- *  This work is based on the LSM implementation in Linux 2.6.13.4.
- *
- *  Author:  George Coker, <gscoker@alpha.ncsc.mil>
- *
- *  Contributors: Michael LeMay, <mdlemay@epoch.ncsc.mil>
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License version 2,
- *  as published by the Free Software Foundation.
- */
-
-#include <xsm/dummy.h>
-
-#define set_to_dummy_if_null(ops, function)                            \
-    do {                                                               \
-        if ( !ops->function )                                          \
-            ops->function = xsm_##function;                            \
-    } while (0)
-
-void __init xsm_fixup_ops (struct xsm_ops *ops)
-{
-    set_to_dummy_if_null(ops, security_domaininfo);
-    set_to_dummy_if_null(ops, domain_create);
-    set_to_dummy_if_null(ops, getdomaininfo);
-    set_to_dummy_if_null(ops, domctl_scheduler_op);
-    set_to_dummy_if_null(ops, sysctl_scheduler_op);
-    set_to_dummy_if_null(ops, set_target);
-    set_to_dummy_if_null(ops, domctl);
-    set_to_dummy_if_null(ops, sysctl);
-    set_to_dummy_if_null(ops, readconsole);
-
-    set_to_dummy_if_null(ops, evtchn_unbound);
-    set_to_dummy_if_null(ops, evtchn_interdomain);
-    set_to_dummy_if_null(ops, evtchn_close_post);
-    set_to_dummy_if_null(ops, evtchn_send);
-    set_to_dummy_if_null(ops, evtchn_status);
-    set_to_dummy_if_null(ops, evtchn_reset);
-
-    set_to_dummy_if_null(ops, grant_mapref);
-    set_to_dummy_if_null(ops, grant_unmapref);
-    set_to_dummy_if_null(ops, grant_setup);
-    set_to_dummy_if_null(ops, grant_transfer);
-    set_to_dummy_if_null(ops, grant_copy);
-    set_to_dummy_if_null(ops, grant_query_size);
-
-    set_to_dummy_if_null(ops, alloc_security_domain);
-    set_to_dummy_if_null(ops, free_security_domain);
-    set_to_dummy_if_null(ops, alloc_security_evtchns);
-    set_to_dummy_if_null(ops, free_security_evtchns);
-    set_to_dummy_if_null(ops, show_security_evtchn);
-    set_to_dummy_if_null(ops, init_hardware_domain);
-
-    set_to_dummy_if_null(ops, get_pod_target);
-    set_to_dummy_if_null(ops, set_pod_target);
-
-    set_to_dummy_if_null(ops, memory_exchange);
-    set_to_dummy_if_null(ops, memory_adjust_reservation);
-    set_to_dummy_if_null(ops, memory_stat_reservation);
-    set_to_dummy_if_null(ops, memory_pin_page);
-    set_to_dummy_if_null(ops, claim_pages);
-
-    set_to_dummy_if_null(ops, console_io);
-
-    set_to_dummy_if_null(ops, profile);
-
-    set_to_dummy_if_null(ops, kexec);
-    set_to_dummy_if_null(ops, schedop_shutdown);
-
-    set_to_dummy_if_null(ops, show_irq_sid);
-    set_to_dummy_if_null(ops, map_domain_pirq);
-    set_to_dummy_if_null(ops, map_domain_irq);
-    set_to_dummy_if_null(ops, unmap_domain_pirq);
-    set_to_dummy_if_null(ops, unmap_domain_irq);
-    set_to_dummy_if_null(ops, bind_pt_irq);
-    set_to_dummy_if_null(ops, unbind_pt_irq);
-    set_to_dummy_if_null(ops, irq_permission);
-    set_to_dummy_if_null(ops, iomem_permission);
-    set_to_dummy_if_null(ops, iomem_mapping);
-    set_to_dummy_if_null(ops, pci_config_permission);
-    set_to_dummy_if_null(ops, get_vnumainfo);
-
-#if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_PCI)
-    set_to_dummy_if_null(ops, get_device_group);
-    set_to_dummy_if_null(ops, assign_device);
-    set_to_dummy_if_null(ops, deassign_device);
-#endif
-
-#if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_DEVICE_TREE)
-    set_to_dummy_if_null(ops, assign_dtdevice);
-    set_to_dummy_if_null(ops, deassign_dtdevice);
-#endif
-
-    set_to_dummy_if_null(ops, resource_plug_core);
-    set_to_dummy_if_null(ops, resource_unplug_core);
-    set_to_dummy_if_null(ops, resource_plug_pci);
-    set_to_dummy_if_null(ops, resource_unplug_pci);
-    set_to_dummy_if_null(ops, resource_setup_pci);
-    set_to_dummy_if_null(ops, resource_setup_gsi);
-    set_to_dummy_if_null(ops, resource_setup_misc);
-
-    set_to_dummy_if_null(ops, page_offline);
-    set_to_dummy_if_null(ops, hypfs_op);
-    set_to_dummy_if_null(ops, hvm_param);
-    set_to_dummy_if_null(ops, hvm_control);
-    set_to_dummy_if_null(ops, hvm_param_altp2mhvm);
-    set_to_dummy_if_null(ops, hvm_altp2mhvm_op);
-
-    set_to_dummy_if_null(ops, do_xsm_op);
-#ifdef CONFIG_COMPAT
-    set_to_dummy_if_null(ops, do_compat_op);
-#endif
-
-    set_to_dummy_if_null(ops, add_to_physmap);
-    set_to_dummy_if_null(ops, remove_from_physmap);
-    set_to_dummy_if_null(ops, map_gmfn_foreign);
-
-    set_to_dummy_if_null(ops, vm_event_control);
-
-#ifdef CONFIG_MEM_ACCESS
-    set_to_dummy_if_null(ops, mem_access);
-#endif
-
-#ifdef CONFIG_MEM_PAGING
-    set_to_dummy_if_null(ops, mem_paging);
-#endif
-
-#ifdef CONFIG_MEM_SHARING
-    set_to_dummy_if_null(ops, mem_sharing);
-#endif
-
-    set_to_dummy_if_null(ops, platform_op);
-#ifdef CONFIG_X86
-    set_to_dummy_if_null(ops, do_mca);
-    set_to_dummy_if_null(ops, shadow_control);
-    set_to_dummy_if_null(ops, mem_sharing_op);
-    set_to_dummy_if_null(ops, apic);
-    set_to_dummy_if_null(ops, machine_memory_map);
-    set_to_dummy_if_null(ops, domain_memory_map);
-    set_to_dummy_if_null(ops, mmu_update);
-    set_to_dummy_if_null(ops, mmuext_op);
-    set_to_dummy_if_null(ops, update_va_mapping);
-    set_to_dummy_if_null(ops, priv_mapping);
-    set_to_dummy_if_null(ops, ioport_permission);
-    set_to_dummy_if_null(ops, ioport_mapping);
-    set_to_dummy_if_null(ops, pmu_op);
-#endif
-    set_to_dummy_if_null(ops, dm_op);
-    set_to_dummy_if_null(ops, xen_version);
-    set_to_dummy_if_null(ops, domain_resource_map);
-#ifdef CONFIG_ARGO
-    set_to_dummy_if_null(ops, argo_enable);
-    set_to_dummy_if_null(ops, argo_register_single_source);
-    set_to_dummy_if_null(ops, argo_register_any_source);
-    set_to_dummy_if_null(ops, argo_send);
-#endif
-}
diff --git a/xen/xsm/silo.c b/xen/xsm/silo.c
index 4ef40bd712..0455e1eb4b 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;
     return -EPERM;
 }
 
diff --git a/xen/xsm/xsm_core.c b/xen/xsm/xsm_core.c
index b5219dff78..75bd2678ef 100644
--- a/xen/xsm/xsm_core.c
+++ b/xen/xsm/xsm_core.c
@@ -18,8 +18,6 @@ 
 #include <xen/hypercall.h>
 #include <xsm/xsm.h>
 
-#ifdef CONFIG_XSM
-
 #ifdef CONFIG_MULTIBOOT
 #include <asm/setup.h>
 #endif
@@ -124,16 +122,12 @@  static int __init xsm_core_init(const void *policy_buffer, size_t policy_size)
         break;
     }
 
-    /*
-     * This handles three cases,
-     *   - dummy policy module was selected
-     *   - a policy module does not provide all handlers
-     *   - a policy module failed to init
-     */
-    xsm_fixup_ops(&xsm_ops);
-
-    if ( xsm_ops_registered != XSM_OPS_REGISTERED )
+    if ( xsm_ops_registered != XSM_OPS_REGISTERED ) {
         xsm_ops_registered = XSM_OPS_REG_FAILED;
+        printk(XENLOG_ERR
+               "Could not init XSM, xsm_ops register failed\n");
+        return -EFAULT;
+    }
 
     return 0;
 }
@@ -217,8 +211,6 @@  bool __init has_xsm_magic(paddr_t start)
 }
 #endif
 
-#endif
-
 long do_xsm_op (XEN_GUEST_HANDLE_PARAM(xsm_op_t) op)
 {
     return xsm_do_xsm_op(op);