diff options
| -rw-r--r-- | arch/x86/xen/p2m.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 8f2251d2a3f..ddc81a06edb 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(); |