[PATCH V2 14/15] Only allow 3-level event channel on Dom0 and driver domain

[Wei Liu <wei.liu2@citrix.com>]

For non-Dom0 domains, add a flag to indicate whether it can use 3-level event
channel, admins can specify this flag when creating a driver domain.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/common/domain.c         |    3 +++
 xen/common/domctl.c         |    5 ++++-
 xen/common/event_channel.c  |    3 +++
 xen/include/public/domctl.h |    3 +++
 xen/include/xen/sched.h     |    5 +++++
 5 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 07f62b3..28405b8 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -250,6 +250,9 @@ struct domain *domain_create(
     if ( domcr_flags & DOMCRF_dummy )
         return d;
 
+    if ( domcr_flags & DOMCRF_evtchn_l3 )
+        d->evtchn_l3 = 1;
+
     if ( !is_idle_domain(d) )
     {
         if ( (err = xsm_domain_create(XSM_HOOK, d, ssidref)) != 0 )
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index a713ce6..fb61e40 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -369,7 +369,8 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
         if ( supervisor_mode_kernel ||
              (op->u.createdomain.flags &
              ~(XEN_DOMCTL_CDF_hvm_guest | XEN_DOMCTL_CDF_hap |
-               XEN_DOMCTL_CDF_s3_integrity | XEN_DOMCTL_CDF_oos_off)) )
+               XEN_DOMCTL_CDF_s3_integrity | XEN_DOMCTL_CDF_oos_off |
+               XEN_DOMCTL_CDF_evtchn_l3)) )
             break;
 
         dom = op->domain;
@@ -405,6 +406,8 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
             domcr_flags |= DOMCRF_s3_integrity;
         if ( op->u.createdomain.flags & XEN_DOMCTL_CDF_oos_off )
             domcr_flags |= DOMCRF_oos_off;
+        if ( op->u.createdomain.flags & XEN_DOMCTL_CDF_evtchn_l3 )
+            domcr_flags |= DOMCRF_evtchn_l3;
 
         d = domain_create(dom, domcr_flags, op->u.createdomain.ssidref);
         if ( IS_ERR(d) )
diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index a91ecba..2d9d0bb 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -1262,6 +1262,9 @@ static long evtchn_register_3level(evtchn_register_3level_t *arg)
     xen_pfn_t l2sel_mfn = 0;
     xen_pfn_t l2sel_offset = 0;
 
+    if ( d->evtchn_l3 == 0 && d->domain_id != 0 )
+        return -EPERM;
+
     if ( d->evtchn_level == EVTCHN_3_LEVEL )
     {
         rc = -EINVAL;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 74160b0..4dacf95 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -59,6 +59,9 @@ struct xen_domctl_createdomain {
  /* Disable out-of-sync shadow page tables? */
 #define _XEN_DOMCTL_CDF_oos_off       3
 #define XEN_DOMCTL_CDF_oos_off        (1U<<_XEN_DOMCTL_CDF_oos_off)
+ /* Can this domain use 3-level event channel? */
+#define _XEN_DOMCTL_CDF_evtchn_l3     4
+#define XEN_DOMCTL_CDF_evtchn_l3    (1U<<_XEN_DOMCTL_CDF_evtchn_l3)
     uint32_t flags;
 };
 typedef struct xen_domctl_createdomain xen_domctl_createdomain_t;
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 1d8c1b5..931655f 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -224,6 +224,8 @@ struct domain
     unsigned int     evtchn_level;
     unsigned long   *evtchn_pending[EVTCHN_MAX_L3_PAGES];
     unsigned long   *evtchn_mask[EVTCHN_MAX_L3_PAGES];
+    /* Can the domain use 3-level event channel? */
+    bool_t           evtchn_l3;
 
     struct grant_table *grant_table;
 
@@ -411,6 +413,9 @@ struct domain *domain_create(
  /* DOMCRF_oos_off: dont use out-of-sync optimization for shadow page tables */
 #define _DOMCRF_oos_off         4
 #define DOMCRF_oos_off          (1U<<_DOMCRF_oos_off)
+/* DOMCRF_evtchn_l3: this domain can use 3-level event channel (driver domain) */
+#define _DOMCRF_evtchn_l3     5
+#define DOMCRF_evtchn_l3      (1U<<_DOMCRF_evtchn_l3)
 
 /*
  * rcu_lock_domain_by_id() is more efficient than get_domain_by_id().
-- 
1.7.10.4