[PATCH 3/5] tools/migration: unify known page type checking

[Andrew Cooper <andrew.cooper3@citrix.com>]

From: Olaf Hering <olaf@aepfle.de>

Users of xc_get_pfn_type_batch may want to sanity check the data
returned by Xen. Add helpers for this purpose:

is_known_page_type verifies the type returned by Xen on the saving
side, or the incoming type for a page on the restoring side, is known
by the save/restore code.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
 tools/libs/guest/xg_sr_common.h  | 29 +++++++++++++++++++++++++++++
 tools/libs/guest/xg_sr_restore.c |  5 ++---
 tools/libs/guest/xg_sr_save.c    |  6 ++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/tools/libs/guest/xg_sr_common.h b/tools/libs/guest/xg_sr_common.h
index e2994e18acf1..e8436d1abb14 100644
--- a/tools/libs/guest/xg_sr_common.h
+++ b/tools/libs/guest/xg_sr_common.h
@@ -455,6 +455,35 @@ int populate_pfns(struct xc_sr_context *ctx, unsigned int count,
 /* Handle a STATIC_DATA_END record. */
 int handle_static_data_end(struct xc_sr_context *ctx);
 
+/* Page type known to the migration logic? */
+static inline bool is_known_page_type(uint32_t type)
+{
+    switch ( type )
+    {
+    case XEN_DOMCTL_PFINFO_NOTAB:
+
+    case XEN_DOMCTL_PFINFO_L1TAB:
+    case XEN_DOMCTL_PFINFO_L1TAB | XEN_DOMCTL_PFINFO_LPINTAB:
+
+    case XEN_DOMCTL_PFINFO_L2TAB:
+    case XEN_DOMCTL_PFINFO_L2TAB | XEN_DOMCTL_PFINFO_LPINTAB:
+
+    case XEN_DOMCTL_PFINFO_L3TAB:
+    case XEN_DOMCTL_PFINFO_L3TAB | XEN_DOMCTL_PFINFO_LPINTAB:
+
+    case XEN_DOMCTL_PFINFO_L4TAB:
+    case XEN_DOMCTL_PFINFO_L4TAB | XEN_DOMCTL_PFINFO_LPINTAB:
+
+    case XEN_DOMCTL_PFINFO_XTAB:
+    case XEN_DOMCTL_PFINFO_XALLOC: /* Synthetic type in Xen 4.2 - 4.5 */
+    case XEN_DOMCTL_PFINFO_BROKEN:
+        return true;
+
+    default:
+        return false;
+    }
+}
+
 #endif
 /*
  * Local variables:
diff --git a/tools/libs/guest/xg_sr_restore.c b/tools/libs/guest/xg_sr_restore.c
index b57a7875192f..508953fd3cf7 100644
--- a/tools/libs/guest/xg_sr_restore.c
+++ b/tools/libs/guest/xg_sr_restore.c
@@ -406,10 +406,9 @@ static int handle_page_data(struct xc_sr_context *ctx, struct xc_sr_record *rec)
         }
 
         type = (pages->pfn[i] & PAGE_DATA_TYPE_MASK) >> 32;
-        if ( ((type >> XEN_DOMCTL_PFINFO_LTAB_SHIFT) >= 5) &&
-             ((type >> XEN_DOMCTL_PFINFO_LTAB_SHIFT) <= 8) )
+        if ( !is_known_page_type(type) )
         {
-            ERROR("Invalid type %#"PRIx32" for pfn %#"PRIpfn" (index %u)",
+            ERROR("Unknown type %#"PRIx32" for pfn %#"PRIpfn" (index %u)",
                   type, pfn, i);
             goto err;
         }
diff --git a/tools/libs/guest/xg_sr_save.c b/tools/libs/guest/xg_sr_save.c
index f0e2bd048d37..c84a073e86f4 100644
--- a/tools/libs/guest/xg_sr_save.c
+++ b/tools/libs/guest/xg_sr_save.c
@@ -147,6 +147,12 @@ static int write_batch(struct xc_sr_context *ctx)
 
     for ( i = 0; i < nr_pfns; ++i )
     {
+        if ( !is_known_page_type(types[i]) )
+        {
+            ERROR("Unknown type %#"PRIpfn" for pfn %#"PRIpfn, types[i], mfns[i]);
+            goto err;
+        }
+
         switch ( types[i] )
         {
         case XEN_DOMCTL_PFINFO_BROKEN:
-- 
2.11.0