xen: add extra pages for E820 RAM regions, even if beyond mem_end

If an entire E820 RAM region is beyond mem_end, still add its
pages to the extra area so that space can be used by the kernel.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index eac010008cd..1e85e26efa6 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -158,9 +158,8 @@ char * __init xen_memory_setup(void)
         xen_extra_mem_start = mem_end;
         for (i = 0; i < memmap.nr_entries; i++) {
                 unsigned long long end = map[i].addr + map[i].size;
+
                 if (map[i].type == E820_RAM) {
-                        if (map[i].addr > mem_end)
-                                continue;
                         if (end > mem_end) {
                                 /* Truncate region to max_mem. */
                                 map[i].size -= end - mem_end;
@@ -169,7 +168,9 @@ char * __init xen_memory_setup(void)
                         }
                 } else if (map[i].type != E820_RAM)
                         xen_extra_mem_start = end;
-                if (map[i].size > 0)
+
+                if ((map[i].type != E820_RAM || map[i].addr < mem_end) &&
+                    map[i].size > 0)
                         e820_add_region(map[i].addr, map[i].size, map[i].type);
         }