[Xen-devel] [PATCH] xen: Add versions of rcu_lock_*_domain without IS_PRIV

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

While this patch is a part of my XSM IS_PRIV series, I am reposting it
alone because the XSM build of xen-unstable is currently broken. I can
also repost the remaining patches series if that would be helpful.

--------------------------------->8----------------------------------

These functions will be used to avoid duplication of IS_PRIV calls
that will be introduced in XSM hooks. This also fixes a build error
with XSM enabled introduced by 25925:d1c3375c3f11 which depends on
this patch.

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 xen/common/domain.c     | 21 +++++++++++++++++++++
 xen/include/xen/sched.h | 11 +++++++++++
 2 files changed, 32 insertions(+)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index a1aa05e..52489b3 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -420,6 +420,13 @@ struct domain *rcu_lock_domain_by_id(domid_t dom)
     return d;
 }
 
+struct domain *rcu_lock_domain_by_any_id(domid_t dom)
+{
+    if ( dom == DOMID_SELF )
+        return rcu_lock_current_domain();
+    return rcu_lock_domain_by_id(dom);
+}
+
 int rcu_lock_target_domain_by_id(domid_t dom, struct domain **d)
 {
     if ( dom == DOMID_SELF )
@@ -454,6 +461,20 @@ int rcu_lock_remote_target_domain_by_id(domid_t dom, 
struct domain **d)
     return 0;
 }
 
+int rcu_lock_remote_domain_by_id(domid_t dom, struct domain **d)
+{
+    if ( (*d = rcu_lock_domain_by_id(dom)) == NULL )
+        return -ESRCH;
+
+    if ( *d == current->domain )
+    {
+        rcu_unlock_domain(*d);
+        return -EPERM;
+    }
+
+    return 0;
+}
+
 int domain_kill(struct domain *d)
 {
     int rc = 0;
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 53804c8..b0def4a 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -447,6 +447,11 @@ struct domain *domain_create(
 struct domain *rcu_lock_domain_by_id(domid_t dom);
 
 /*
+ * As above function, but resolves DOMID_SELF to current domain
+ */
+struct domain *rcu_lock_domain_by_any_id(domid_t dom);
+
+/*
  * As above function, but accounts for current domain context:
  *  - Translates target DOMID_SELF into caller's domain id; and
  *  - Checks that caller has permission to act on the target domain.
@@ -460,6 +465,12 @@ int rcu_lock_target_domain_by_id(domid_t dom, struct 
domain **d);
  */
 int rcu_lock_remote_target_domain_by_id(domid_t dom, struct domain **d);
 
+/*
+ * As rcu_lock_domain_by_id(), but will fail EPERM or ESRCH rather than resolve
+ * to local domain.
+ */
+int rcu_lock_remote_domain_by_id(domid_t dom, struct domain **d);
+
 /* Finish a RCU critical region started by rcu_lock_domain_by_id(). */
 static inline void rcu_unlock_domain(struct domain *d)
 {
-- 
1.7.11.7


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