[PATCH 6/7] xen: Allow hardare domain != dom0

[Daniel De Graaf <dgdegra@tycho.nsa.gov>]

This adds a hypervisor command line option "hardware_dom=" which takes a
domain ID.  When the domain with this ID is created, it will be used
as the hardware domain.

This is intended to be used when domain 0 is a dedicated stub domain for
domain building, allowing the hardware domain to be de-privileged and
act only as a driver domain.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
---
 xen/arch/x86/domain_build.c         |  4 +++-
 xen/arch/x86/setup.c                |  2 ++
 xen/common/domain.c                 |  1 +
 xen/common/domctl.c                 | 41 +++++++++++++++++++++++++++++++++++++
 xen/common/rangeset.c               | 40 ++++++++++++++++++++++++++++++++++++
 xen/include/xen/rangeset.h          |  3 +++
 xen/include/xen/sched.h             |  3 ++-
 xen/include/xsm/dummy.h             |  6 ++++++
 xen/include/xsm/xsm.h               |  6 ++++++
 xen/xsm/dummy.c                     |  2 ++
 xen/xsm/flask/hooks.c               |  6 ++++++
 xen/xsm/flask/policy/access_vectors |  2 ++
 12 files changed, 114 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index f75f6e7..a554d3b 100644
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -1150,7 +1150,9 @@ int __init construct_dom0(
         printk(" Xen warning: dom0 kernel broken ELF: %s\n",
                elf_check_broken(&elf));
 
-    iommu_hwdom_init(hardware_domain);
+    if ( is_hardware_domain(d) )
+        iommu_hwdom_init(d);
+
     return 0;
 
 out:
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 75cf212..f246ac3 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -84,6 +84,8 @@ unsigned long __initdata highmem_start;
 size_param("highmem-start", highmem_start);
 #endif
 
+integer_param("hardware_dom", hardware_domid);
+
 cpumask_t __read_mostly cpu_present_map;
 
 unsigned long __read_mostly xen_phys_start;
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6a282a2..a77f8af 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -60,6 +60,7 @@ static struct domain *domain_hash[DOMAIN_HASH_SIZE];
 struct domain *domain_list;
 
 struct domain *hardware_domain __read_mostly;
+domid_t hardware_domid __read_mostly;
 
 struct vcpu *idle_vcpu[NR_CPUS] __read_mostly;
 
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index eebeee7..57bb026 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -472,6 +472,47 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
             break;
         }
 
+#ifdef CONFIG_LATE_HWDOM
+        if ( is_hardware_domain(d) )
+        {
+            struct domain *dom0 = hardware_domain;
+            ASSERT(dom0->domain_id == 0);
+
+            ret = xsm_init_hardware_domain(XSM_HOOK, d);
+            if ( ret )
+            {
+                domain_kill(d);
+                d = NULL;
+                break;
+            }
+
+            printk("Initialising hardware domain %d\n", hardware_domid);
+            hardware_domain = d;
+
+            /*
+             * Hardware resource ranges for domain 0 have been set up from
+             * various sources intended to restrict the hardware domain's
+             * access.  Apply these ranges to the actual hardware domain.
+             *
+             * Because the lists are being swapped, a side effect of this
+             * operation is that Domain 0's rangesets are cleared.  Since
+             * domain 0 should not be accessing the hardware when it constructs
+             * a hardware domain, this should not be a problem.  Both lists
+             * may be modified after this hypercall returns if a more complex
+             * device model is desired.
+             *
+             * Since late hardware domain initialization is only supported on
+             * x86, the reference to arch.ioport_caps does not need its own
+             * preprocessor conditional.
+             */
+            rangeset_swap(d->irq_caps, dom0->irq_caps);
+            rangeset_swap(d->iomem_caps, dom0->iomem_caps);
+            rangeset_swap(d->arch.ioport_caps, dom0->arch.ioport_caps);
+
+            iommu_hwdom_init(d);
+        }
+#endif
+
         ret = 0;
 
         memcpy(d->handle, op->u.createdomain.handle,
diff --git a/xen/common/rangeset.c b/xen/common/rangeset.c
index f09c0c4..52fae1f 100644
--- a/xen/common/rangeset.c
+++ b/xen/common/rangeset.c
@@ -438,3 +438,43 @@ void rangeset_domain_printk(
 
     spin_unlock(&d->rangesets_lock);
 }
+
+void rangeset_swap(struct rangeset *a, struct rangeset *b)
+{
+    struct list_head tmp;
+    if (&a < &b)
+    {
+        spin_lock(&a->lock);
+        spin_lock(&b->lock);
+    }
+    else
+    {
+        spin_lock(&b->lock);
+        spin_lock(&a->lock);
+    }
+    memcpy(&tmp, &a->range_list, sizeof(tmp));
+    memcpy(&a->range_list, &b->range_list, sizeof(tmp));
+    memcpy(&b->range_list, &tmp, sizeof(tmp));
+    if ( a->range_list.next == &b->range_list )
+    {
+        a->range_list.next = &a->range_list;
+        a->range_list.prev = &a->range_list;
+    }
+    else
+    {
+        a->range_list.next->prev = &a->range_list;
+        a->range_list.prev->next = &a->range_list;
+    }
+    if ( b->range_list.next == &a->range_list )
+    {
+        b->range_list.next = &b->range_list;
+        b->range_list.prev = &b->range_list;
+    }
+    else
+    {
+        b->range_list.next->prev = &b->range_list;
+        b->range_list.prev->next = &b->range_list;
+    }
+    spin_unlock(&a->lock);
+    spin_unlock(&b->lock);
+}
diff --git a/xen/include/xen/rangeset.h b/xen/include/xen/rangeset.h
index 1e16a6b..805ebde 100644
--- a/xen/include/xen/rangeset.h
+++ b/xen/include/xen/rangeset.h
@@ -73,4 +73,7 @@ void rangeset_printk(
 void rangeset_domain_printk(
     struct domain *d);
 
+/* swap contents */
+void rangeset_swap(struct rangeset *a, struct rangeset *b);
+
 #endif /* __XEN_RANGESET_H__ */
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 91adc8c..8b28f79 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -45,6 +45,7 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_runstate_info_compat_t);
 
 /* A global pointer to the hardware domain (usually DOM0). */
 extern struct domain *hardware_domain;
+extern domid_t hardware_domid;
 
 #ifndef CONFIG_COMPAT
 #define BITS_PER_EVTCHN_WORD(d) BITS_PER_XEN_ULONG
@@ -794,7 +795,7 @@ void watchdog_domain_destroy(struct domain *d);
  *    (that is, this would not be suitable for a driver domain)
  *  - There is never a reason to deny dom0 access to this
  */
-#define is_hardware_domain(_d) ((_d)->domain_id == 0)
+#define is_hardware_domain(d)  ((d)->domain_id == hardware_domid)
 
 /* This check is for functionality specific to a control domain */
 #define is_control_domain(_d) ((_d)->is_privileged)
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index e722155..8ca1117 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -299,6 +299,12 @@ static XSM_INLINE char *xsm_show_security_evtchn(struct domain *d, const struct
     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);
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 15acb3b..bff0574 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -82,6 +82,7 @@ struct xsm_operations {
     int (*alloc_security_evtchn) (struct evtchn *chn);
     void (*free_security_evtchn) (struct evtchn *chn);
     char *(*show_security_evtchn) (struct domain *d, const struct evtchn *chn);
+    int (*init_hardware_domain) (struct domain *d);
 
     int (*get_pod_target) (struct domain *d);
     int (*set_pod_target) (struct domain *d);
@@ -311,6 +312,11 @@ static inline char *xsm_show_security_evtchn (struct domain *d, const struct evt
     return xsm_ops->show_security_evtchn(d, chn);
 }
 
+static inline int xsm_init_hardware_domain (xsm_default_t def, struct domain *d)
+{
+    return xsm_ops->init_hardware_domain(d);
+}
+
 static inline int xsm_get_pod_target (xsm_default_t def, struct domain *d)
 {
     return xsm_ops->get_pod_target(d);
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index b79e10f..c2804f2 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -58,6 +58,8 @@ void xsm_fixup_ops (struct xsm_operations *ops)
     set_to_dummy_if_null(ops, alloc_security_evtchn);
     set_to_dummy_if_null(ops, free_security_evtchn);
     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);
 
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 4ce31c9..f1a4a2d 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -327,6 +327,11 @@ static char *flask_show_security_evtchn(struct domain *d, const struct evtchn *c
     return ctx;
 }
 
+static int flask_init_hardware_domain(struct domain *d)
+{
+    return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__CREATE_HARDWARE_DOMAIN);
+}
+
 static int flask_grant_mapref(struct domain *d1, struct domain *d2, 
                               uint32_t flags)
 {
@@ -1500,6 +1505,7 @@ static struct xsm_operations flask_ops = {
     .alloc_security_evtchn = flask_alloc_security_evtchn,
     .free_security_evtchn = flask_free_security_evtchn,
     .show_security_evtchn = flask_show_security_evtchn,
+    .init_hardware_domain = flask_init_hardware_domain,
 
     .get_pod_target = flask_get_pod_target,
     .set_pod_target = flask_set_pod_target,
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index a0ed13d..32371a9 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -198,6 +198,8 @@ class domain2
     set_max_evtchn
 # XEN_DOMCTL_cacheflush
     cacheflush
+# Creation of the hardware domain when it is not dom0
+    create_hardware_domain
 }
 
 # Similar to class domain, but primarily contains domctls related to HVM domains
-- 
1.8.5.3