xen/page_alloc: statically allocate bootmem_region_list

The existing code assumes that the first mfn passed to the boot
allocator is mapped, which creates problems when, e.g., we do not have
a direct map, and may create other bootstrapping problems in the
future. Make it static. The size is kept the same as before (1 page).

Signed-off-by: Hongyan Xia <hongyxia@amazon.com>
Reviewed-by: Julien Grall <julien@xen.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit c61c1b49430527ee16fbf5b55aca195c325b1a23)

This patch is necessary for liveupdate to prevent the boot allocator to
use the first page of the ranges passed. This page may belong to a
domain restored.

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 489548063abb13d59e9fe1293dca577df8e6ea1b..8104fd07dba96b81d7642739cce8432c842e3331 100644 (file)
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -199,9 +199,12 @@ PAGE_LIST_HEAD(page_broken_list);
  */
 mfn_t first_valid_mfn = INVALID_MFN_INITIALIZER;
 
-static struct bootmem_region {
+struct bootmem_region {
     unsigned long s, e; /* MFNs @s through @e-1 inclusive are free */
-} *__initdata bootmem_region_list;
+};
+/* Statically allocate a page for bootmem_region_list. */
+static struct bootmem_region __initdata
+    bootmem_region_list[PAGE_SIZE / sizeof(struct bootmem_region)];
 static unsigned int __initdata nr_bootmem_regions;
 
 struct scrub_region {
@@ -218,9 +221,6 @@ static void __init bootmem_region_add(unsigned long s, unsigned long e)
 {
     unsigned int i;
 
-    if ( (bootmem_region_list == NULL) && (s < e) )
-        bootmem_region_list = mfn_to_virt(s++);
-
     if ( s >= e )
         return;
 
@@ -1816,7 +1816,6 @@ void __init end_boot_allocator(void)
             init_heap_pages(mfn_to_page(_mfn(r->s)), r->e - r->s);
     }
     nr_bootmem_regions = 0;
-    init_heap_pages(virt_to_page(bootmem_region_list), 1);
 
     if ( !dma_bitsize && (num_online_nodes() > 1) )
         dma_bitsize = arch_get_dma_bitsize();