libxc: introduce xc_map_domain_meminfo (and xc_unmap_domain_meminfo)

And use it in xc_exchange_page(). This is basically because the
following change need something really similar to the set of
steps that are here abstracted in these two functions.

Despite of the change in the interface and in the signature of
some functions, this is pure code motion. No functional changes
involved.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/tools/libxc/xg_private.h b/tools/libxc/xg_private.h
index db02ccf470..5ff2124346 100644
--- a/tools/libxc/xg_private.h
+++ b/tools/libxc/xg_private.h
@@ -136,6 +136,15 @@ struct domain_info_context {
     unsigned long p2m_size;
 };
 
+static inline xen_pfn_t pfn_to_mfn(xen_pfn_t pfn, xen_pfn_t *p2m, int gwidth)
+{
+  return ((xen_pfn_t) ((gwidth==8)?
+                       (((uint64_t *)p2m)[(pfn)]):
+                       ((((uint32_t *)p2m)[(pfn)]) == 0xffffffffU ?
+                            (-1UL) :
+                            (((uint32_t *)p2m)[(pfn)]))));
+}
+
 /* Number of xen_pfn_t in a page */
 #define FPP             (PAGE_SIZE/(dinfo->guest_width))