- memcpy(map_raw, map, sizeof(map));
- e820.nr_map = 0;
- xen_extra_mem[0].start = mem_end;
- for (i = 0; i < memmap.nr_entries; i++) {
- unsigned long long end;
-
- /* Guard against non-page aligned E820 entries. */
- if (map[i].type == E820_RAM)
- map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
-
- end = map[i].addr + map[i].size;
- if (map[i].type == E820_RAM && end > mem_end) {
- /* RAM off the end - may be partially included */
- u64 delta = min(map[i].size, end - mem_end);
-
- map[i].size -= delta;
- end -= delta;
-
- extra_pages += PFN_DOWN(delta);
- /*
- * Set RAM below 4GB that is not for us to be unusable.
- * This prevents "System RAM" address space from being
- * used as potential resource for I/O address (happens
- * when 'allocate_resource' is called).
- */
- if (delta &&
- (xen_initial_domain() && end < 0x100000000ULL))
- e820_add_region(end, delta, E820_UNUSABLE);
+ /* Make sure the Xen-supplied memory map is well-ordered. */
+ sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
+
+ max_pages = xen_get_max_pages();
+ if (max_pages > max_pfn)
+ extra_pages += max_pages - max_pfn;
+
+ xen_released_pages = xen_return_unused_memory(max_pfn, map,
+ memmap.nr_entries);
+ extra_pages += xen_released_pages;
+
+ /*
+ * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
+ * factor the base size. On non-highmem systems, the base
+ * size is the full initial memory allocation; on highmem it
+ * is limited to the max size of lowmem, so that it doesn't
+ * get completely filled.
+ *
+ * In principle there could be a problem in lowmem systems if
+ * the initial memory is also very large with respect to
+ * lowmem, but we won't try to deal with that here.
+ */
+ extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+ extra_pages);
+
+ i = 0;
+ while (i < memmap.nr_entries) {
+ u64 addr = map[i].addr;
+ u64 size = map[i].size;
+ u32 type = map[i].type;
+
+ if (type == E820_RAM) {
+ if (addr < mem_end) {
+ size = min(size, mem_end - addr);
+ } else if (extra_pages) {
+ size = min(size, (u64)extra_pages * PAGE_SIZE);
+ extra_pages -= size / PAGE_SIZE;
+ xen_add_extra_mem(addr, size);
+ } else
+ type = E820_UNUSABLE;