sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
extra_limit = xen_get_max_pages();
- if (extra_limit >= max_pfn)
- extra_pages = extra_limit - max_pfn;
- else
- extra_pages = 0;
+ if (max_pfn + extra_pages > extra_limit) {
+ if (extra_limit > max_pfn)
+ extra_pages = extra_limit - max_pfn;
+ else
+ extra_pages = 0;
+ }
extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);