[Xen-devel] [PATCH] Re: Who uses xc_gnttab_map_grant_refs?

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>]

Ian Jackson, le Fri 18 Jul 2008 15:55:58 +0100, a écrit :
> Samuel Thibault writes ("Re: [Xen-devel] Who uses xc_gnttab_map_grant_refs?"):
> > But still kill the old function at least?
> 
> Is that a change we want to make at this stage of the release ?  I
> don't necessarily have an opinion but it's a question we should be
> asking.

Ok, well, here is a patch that keeps the old function, just making its
implementation an internal with an additional domids_stride parameter in
order to also both efficiency.

Samuel



libxc: add xc_gnttab_map_domain_grant_refs.

xc_gnttab_map_domain_grant_refs permits to simply map several pages from
the same domain.

Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>

diff -r 3139383b36a0 tools/libxc/xc_linux.c
--- a/tools/libxc/xc_linux.c    Fri Jul 18 18:13:53 2008 +0100
+++ b/tools/libxc/xc_linux.c    Mon Jul 21 11:44:43 2008 +0100
@@ -418,9 +418,10 @@
     return addr;
 }
 
-void *xc_gnttab_map_grant_refs(int xcg_handle,
+static void *do_gnttab_map_grant_refs(int xcg_handle,
                                uint32_t count,
                                uint32_t *domids,
+                               int domids_stride,
                                uint32_t *refs,
                                int prot)
 {
@@ -435,7 +436,7 @@
 
     for ( i = 0; i < count; i++ )
     {
-        map->refs[i].domid = domids[i];
+        map->refs[i].domid = domids[i * domids_stride];
         map->refs[i].ref   = refs[i];
     }
 
@@ -462,6 +463,24 @@
  out:
     free(map);
     return addr;
+}
+
+void *xc_gnttab_map_grant_refs(int xcg_handle,
+                               uint32_t count,
+                               uint32_t *domids,
+                               uint32_t *refs,
+                               int prot)
+{
+    return do_gnttab_map_grant_refs(xcg_handle, count, domids, 1, refs, prot);
+}
+
+void *xc_gnttab_map_domain_grant_refs(int xcg_handle,
+                               uint32_t count,
+                               uint32_t domid,
+                               uint32_t *refs,
+                               int prot)
+{
+    return do_gnttab_map_grant_refs(xcg_handle, count, &domid, 0, refs, prot);
 }
 
 int xc_gnttab_munmap(int xcg_handle,
diff -r 3139383b36a0 tools/libxc/xenctrl.h
--- a/tools/libxc/xenctrl.h     Fri Jul 18 18:13:53 2008 +0100
+++ b/tools/libxc/xenctrl.h     Mon Jul 21 11:44:43 2008 +0100
@@ -865,6 +865,23 @@
                                uint32_t *refs,
                                int prot);
 
+/**
+ * Memory maps one or more grant references from one domain to a
+ * contiguous local address range. Mappings should be unmapped with
+ * xc_gnttab_munmap.  Returns NULL on failure.
+ *
+ * @parm xcg_handle a handle on an open grant table interface
+ * @parm count the number of grant references to be mapped
+ * @parm domid the domain to map memory from
+ * @parm refs an array of @count grant references to be mapped
+ * @parm prot same flag as in mmap()
+ */
+void *xc_gnttab_map_domain_grant_refs(int xcg_handle,
+                                      uint32_t count,
+                                      uint32_t domid,
+                                      uint32_t *refs,
+                                      int prot);
+
 /*
  * Unmaps the @count pages starting at @start_address, which were mapped by a
  * call to xc_gnttab_map_grant_ref or xc_gnttab_map_grant_refs. Returns zero

Attachment: patch
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