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Diffstat (limited to 'arch/x86/xen/p2m.c')
-rw-r--r--arch/x86/xen/p2m.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8f2251d2a3f8..ddc81a06edb9 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -237,7 +237,25 @@ void __init xen_build_dynamic_phys_to_machine(void)
p2m_top[topidx] = mid;
}
- p2m_top[topidx][mididx] = &mfn_list[pfn];
+ /*
+ * As long as the mfn_list has enough entries to completely
+ * fill a p2m page, pointing into the array is ok. But if
+ * not the entries beyond the last pfn will be undefined.
+ * And guessing that the 'what-ever-there-is' does not take it
+ * too kindly when changing it to invalid markers, a new page
+ * is allocated, initialized and filled with the valid part.
+ */
+ if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) {
+ unsigned long p2midx;
+ unsigned long *p2m = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_init(p2m);
+
+ for (p2midx = 0; pfn + p2midx < max_pfn; p2midx++) {
+ p2m[p2midx] = mfn_list[pfn + p2midx];
+ }
+ p2m_top[topidx][mididx] = p2m;
+ } else
+ p2m_top[topidx][mididx] = &mfn_list[pfn];
}
m2p_override_init();