[PATCH V7 1/5] x86/mm: introduce p2m_{init, free}_logdirty()

[Razvan Cojocaru <rcojocaru@bitdefender.com>]

Add logdirty_ranges allocator / deallocator helpers.
p2m_init_logdirty() will not re-allocate if
p2m->logdirty ranges has already been allocated.

Move the rangeset deallocation call from p2m_teardown_hostp2m()
to p2m_free_one() - we will want this to apply to altp2ms
as well.

Signed-off-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>

---
CC: George Dunlap <george.dunlap@eu.citrix.com>
CC: Jan Beulich <jbeulich@suse.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>

---
Changes since V6:
 - Added George's Reviewed-by.
---
 xen/arch/x86/mm/p2m.c | 46 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 6a1abb6..418ff85 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -59,6 +59,28 @@ static void p2m_nestedp2m_init(struct p2m_domain *p2m)
 #endif
 }
 
+static int p2m_init_logdirty(struct p2m_domain *p2m)
+{
+    if ( p2m->logdirty_ranges )
+        return 0;
+
+    p2m->logdirty_ranges = rangeset_new(p2m->domain, "log-dirty",
+                                        RANGESETF_prettyprint_hex);
+    if ( !p2m->logdirty_ranges )
+        return -ENOMEM;
+
+    return 0;
+}
+
+static void p2m_free_logdirty(struct p2m_domain *p2m)
+{
+    if ( !p2m->logdirty_ranges )
+        return;
+
+    rangeset_destroy(p2m->logdirty_ranges);
+    p2m->logdirty_ranges = NULL;
+}
+
 /* Init the datastructures for later use by the p2m code */
 static int p2m_initialise(struct domain *d, struct p2m_domain *p2m)
 {
@@ -107,6 +129,7 @@ free_p2m:
 
 static void p2m_free_one(struct p2m_domain *p2m)
 {
+    p2m_free_logdirty(p2m);
     if ( hap_enabled(p2m->domain) && cpu_has_vmx )
         ept_p2m_uninit(p2m);
     free_cpumask_var(p2m->dirty_cpumask);
@@ -116,19 +139,19 @@ static void p2m_free_one(struct p2m_domain *p2m)
 static int p2m_init_hostp2m(struct domain *d)
 {
     struct p2m_domain *p2m = p2m_init_one(d);
+    int rc;
 
-    if ( p2m )
-    {
-        p2m->logdirty_ranges = rangeset_new(d, "log-dirty",
-                                            RANGESETF_prettyprint_hex);
-        if ( p2m->logdirty_ranges )
-        {
-            d->arch.p2m = p2m;
-            return 0;
-        }
+    if ( !p2m )
+        return -ENOMEM;
+
+    rc = p2m_init_logdirty(p2m);
+
+    if ( !rc )
+        d->arch.p2m = p2m;
+    else
         p2m_free_one(p2m);
-    }
-    return -ENOMEM;
+
+    return rc;
 }
 
 static void p2m_teardown_hostp2m(struct domain *d)
@@ -138,7 +161,6 @@ static void p2m_teardown_hostp2m(struct domain *d)
 
     if ( p2m )
     {
-        rangeset_destroy(p2m->logdirty_ranges);
         p2m_free_one(p2m);
         d->arch.p2m = NULL;
     }
-- 
2.7.4


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