+#ifdef CONFIG_X86_64
+#include <linux/bootmem.h>
+unsigned long __init xen_revector_p2m_tree(void)
+{
+ unsigned long va_start;
+ unsigned long va_end;
+ unsigned long pfn;
+ unsigned long pfn_free = 0;
+ unsigned long *mfn_list = NULL;
+ unsigned long size;
+
+ va_start = xen_start_info->mfn_list;
+ /*We copy in increments of P2M_PER_PAGE * sizeof(unsigned long),
+ * so make sure it is rounded up to that */
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+ va_end = va_start + size;
+
+ /* If we were revectored already, don't do it again. */
+ if (va_start <= __START_KERNEL_map && va_start >= __PAGE_OFFSET)
+ return 0;
+
+ mfn_list = alloc_bootmem_align(size, PAGE_SIZE);
+ if (!mfn_list) {
+ pr_warn("Could not allocate space for a new P2M tree!\n");
+ return xen_start_info->mfn_list;
+ }
+ /* Fill it out with INVALID_P2M_ENTRY value */
+ memset(mfn_list, 0xFF, size);
+
+ for (pfn = 0; pfn < ALIGN(MAX_DOMAIN_PAGES, P2M_PER_PAGE); pfn += P2M_PER_PAGE) {
+ unsigned topidx = p2m_top_index(pfn);
+ unsigned mididx;
+ unsigned long *mid_p;
+
+ if (!p2m_top[topidx])
+ continue;
+
+ if (p2m_top[topidx] == p2m_mid_missing)
+ continue;
+
+ mididx = p2m_mid_index(pfn);
+ mid_p = p2m_top[topidx][mididx];
+ if (!mid_p)
+ continue;
+ if ((mid_p == p2m_missing) || (mid_p == p2m_identity))
+ continue;
+
+ if ((unsigned long)mid_p == INVALID_P2M_ENTRY)
+ continue;
+
+ /* The old va. Rebase it on mfn_list */
+ if (mid_p >= (unsigned long *)va_start && mid_p <= (unsigned long *)va_end) {
+ unsigned long *new;
+
+ if (pfn_free > (size / sizeof(unsigned long))) {
+ WARN(1, "Only allocated for %ld pages, but we want %ld!\n",
+ size / sizeof(unsigned long), pfn_free);
+ return 0;
+ }
+ new = &mfn_list[pfn_free];
+
+ copy_page(new, mid_p);
+ p2m_top[topidx][mididx] = &mfn_list[pfn_free];
+ p2m_top_mfn_p[topidx][mididx] = virt_to_mfn(&mfn_list[pfn_free]);
+
+ pfn_free += P2M_PER_PAGE;