[Xen-devel] [PATCH v4 05/31] x86/mm: document the return values from get_page_from_l*e

[Wei Liu <wei.liu2@xxxxxxxxxx>]

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/arch/x86/mm.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 64dd520044..5983a56811 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -869,6 +869,12 @@ static int print_mmio_emul_range(unsigned long s, unsigned 
long e, void *arg)
 }
 #endif
 
+/*
+ * get_page_from_l1e returns:
+ *   0  => success (page not present also counts as such)
+ *  <0  => error code
+ *  >0  => the page flags to be flipped
+ */
 int
 get_page_from_l1e(
     l1_pgentry_t l1e, struct domain *l1e_owner, struct domain *pg_owner)
@@ -1081,6 +1087,12 @@ get_page_from_l1e(
 
 
 /* NB. Virtual address 'l2e' maps to a machine address within frame 'pfn'. */
+/*
+ * get_page_from_l2e returns:
+ *   1 => page not present
+ *   0 => success
+ *  <0 => error code
+ */
 define_get_linear_pagetable(l2);
 static int
 get_page_from_l2e(
@@ -1111,6 +1123,12 @@ get_page_from_l2e(
 }
 
 
+/*
+ * get_page_from_l3e returns:
+ *   1 => page not present
+ *   0 => success
+ *  <0 => error code
+ */
 define_get_linear_pagetable(l3);
 static int
 get_page_from_l3e(
@@ -1138,6 +1156,12 @@ get_page_from_l3e(
     return rc;
 }
 
+/*
+ * get_page_from_l4e returns:
+ *   1 => page not present
+ *   0 => success
+ *  <0 => error code
+ */
 define_get_linear_pagetable(l4);
 static int
 get_page_from_l4e(
-- 
2.11.0


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