Reset to 3.12.19

1 files changed, 18 insertions, 6 deletions

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index b232908..4c437ef 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -405,11 +405,25 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 			state = BP_EAGAIN;
 			break;
 		}
+		scrub_page(page);
 
-		pfn = page_to_pfn(page);
-		frame_list[i] = pfn_to_mfn(pfn);
+		frame_list[i] = page_to_pfn(page);
+	}
 
-		scrub_page(page);
+	/*
+	 * Ensure that ballooned highmem pages don't have kmaps.
+	 *
+	 * Do this before changing the p2m as kmap_flush_unused()
+	 * reads PTEs to obtain pages (and hence needs the original
+	 * p2m entry).
+	 */
+	kmap_flush_unused();
+
+	/* Update direct mapping, invalidate P2M, and add to balloon. */
+	for (i = 0; i < nr_pages; i++) {
+		pfn = frame_list[i];
+		frame_list[i] = pfn_to_mfn(pfn);
+		page = pfn_to_page(pfn);
 
 		/*
 		 * Ballooned out frames are effectively replaced with
@@ -433,11 +447,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
 		}
 		put_balloon_scratch_page();
 
-		balloon_append(pfn_to_page(pfn));
+		balloon_append(page);
 	}
 
-	/* Ensure that ballooned highmem pages don't have kmaps. */
-	kmap_flush_unused();
 	flush_tlb_all();
 
 	set_xen_guest_handle(reservation.extent_start, frame_list);