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xen/p2m: Mark INVALID_P2M_ENTRY the mfn_list past max_pfn.

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In case the mfn_list does not have enough entries to fill
a p2m page we do not want the entries from max_pfn up to
the boundary to be filled with unknown values. Hence
set them to INVALID_P2M_ENTRY.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Stefan Bader 2011-01-27 10:03:14 -05:00 committed by Konrad Rzeszutek Wilk
parent 1bae4ce27c
commit cf04d120d9
1 changed files with 5 additions and 11 deletions
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12
arch/x86/xen/p2m.c
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@ -241,20 +241,14 @@ void __init xen_build_dynamic_phys_to_machine(void)
* 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];
p2midx = max_pfn % P2M_PER_PAGE;
for ( ; p2midx < P2M_PER_PAGE; p2midx++)
mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY;
}
p2m_top[topidx][mididx] = p2m;
} else
p2m_top[topidx][mididx] = &mfn_list[pfn];
}