x86/mm: revert 26399:b0e618cb0233 (multiple vram areas)

Although this passed my smoke-tests at commit time, I'm now seeing screen
corruption on 32-bit WinXP guests.  Reverting for now. :(

Signed-off-by: Tim Deegan <tim@xen.org>
Committed-by: Tim Deegan <tim@xen.org>

1 files changed, 6 insertions, 14 deletions

diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index cd4e1ef0d8..32122fd303 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -1563,23 +1563,15 @@ int xc_hvm_inject_msi(
     xc_interface *xch, domid_t dom, uint64_t addr, uint32_t data);
 
 /*
- * Track dirty bit changes in a VRAM region defined by
- * [ first_pfn : first_pfn + nr - 1 ]
+ * Track dirty bit changes in the VRAM area
  *
  * All of this is done atomically:
- * - gets the dirty bitmap since the last call, all zeroes for
- *   the first call with some new region
- * - sets up a dirty tracking region for period up to the next call
- * - clears the specified dirty tracking region.
+ * - get the dirty bitmap since the last call
+ * - set up dirty tracking area for period up to the next call
+ * - clear the dirty tracking area.
  *
- * Creating a new region causes any existing regions that it overlaps
- * to be discarded.
- *
- * Specifying nr == 0 causes all regions to be discarded and
- * disables dirty bit tracking.
- *
- * If nr is not a multiple of 64, only the first nr bits of bitmap
- * are well defined.
+ * Returns -ENODATA and does not fill bitmap if the area has changed since the
+ * last call.
  */
 int xc_hvm_track_dirty_vram(
     xc_interface *xch, domid_t dom,