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-rw-r--r--drivers/xen/balloon.c24
1 files changed, 18 insertions, 6 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 37d06ea624aa..61a6ac8fa8fc 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -399,11 +399,25 @@ 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);
#ifdef CONFIG_XEN_HAVE_PVMMU
/*
@@ -429,11 +443,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
}
#endif
- 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);