[PATCH RFC v2 04/12] xen/mem_event: Abstract architecture specific sanity checks

[Tamas K Lengyel <tklengyel@sec.in.tum.de>]

Move architecture specific sanity checks into its own function
which is called when enabling mem_event.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
 xen/common/mem_event.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/xen/common/mem_event.c b/xen/common/mem_event.c
index 8be32e1..8bf0cf1 100644
--- a/xen/common/mem_event.c
+++ b/xen/common/mem_event.c
@@ -424,6 +424,19 @@ int __mem_event_claim_slot(struct domain *d, struct mem_event_domain *med,
         return mem_event_grab_slot(med, (current->domain != d));
 }
 
+static inline bool_t mem_event_sanity_check(struct domain *d)
+{
+    /* Only HAP is supported */
+    if ( !hap_enabled(d) )
+        return 0;
+
+    /* Currently only EPT is supported */
+    if ( !cpu_has_vmx )
+        return 0;
+
+    return 1;
+}
+
 /* Registered with Xen-bound event channel for incoming notifications. */
 static void mem_paging_notification(struct vcpu *v, unsigned int port)
 {
@@ -558,6 +571,7 @@ int mem_event_domctl(struct domain *d, xen_domctl_mem_event_op_t *mec,
             rc = -EMLINK;
             if ( unlikely(need_iommu(d)) )
                 break;
+            }
 
             rc = -EXDEV;
             /* Disallow paging in a PoD guest */
@@ -593,14 +607,11 @@ int mem_event_domctl(struct domain *d, xen_domctl_mem_event_op_t *mec,
         {
         case XEN_DOMCTL_MEM_EVENT_OP_ACCESS_ENABLE:
         {
-            rc = -ENODEV;
-            /* Only HAP is supported */
-            if ( !hap_enabled(d) )
-                break;
-
-            /* Currently only EPT is supported */
-            if ( !cpu_has_vmx )
+            if ( !mem_event_sanity_check(d) )
+            {
+                rc = -ENODEV;
                 break;
+            }
 
             rc = mem_event_enable(d, mec, med, _VPF_mem_access,
                                     HVM_PARAM_ACCESS_RING_PFN,
-- 
2.1.0.rc1