libxc: fix uninitialised usage of rc in meminit_hvm

Due to the HVMlite changes there's a chance that the value in rc is checked
without being initialised. Fix this by initialising it to 0 prior to the
while loop. Also add a specific error check to a previous populate_physmap
call, this prevents us from overwriting this error.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
index ef474a80894818e9850e443d2d445000aceca911..2a3f64b89b2460937960fe3626261a2157f58ed9 100644 (file)
--- a/tools/libxc/xc_dom_x86.c
+++ b/tools/libxc/xc_dom_x86.c
@@ -1412,8 +1412,15 @@ static int meminit_hvm(struct xc_dom_image *dom)
      * ensure that we can be preempted and hence dom0 remains responsive.
      */
     if ( dom->device_model )
+    {
         rc = xc_domain_populate_physmap_exact(
             xch, domid, 0xa0, 0, memflags, &dom->p2m_host[0x00]);
+        if ( rc != 0 )
+        {
+            DOMPRINTF("Could not populate low memory (< 0xA0).\n");
+            goto error_out;
+        }
+    }
 
     stat_normal_pages = 0;
     for ( vmemid = 0; vmemid < nr_vmemranges; vmemid++ )
@@ -1440,6 +1447,7 @@ static int meminit_hvm(struct xc_dom_image *dom)
         else
             cur_pages = vmemranges[vmemid].start >> PAGE_SHIFT;
 
+        rc = 0;
         while ( (rc == 0) && (end_pages > cur_pages) )
         {
             /* Clip count to maximum 1GB extent. */