x86/xen: add extra memory for remapped frames during setup

If the non-RAM regions in the e820 memory map are larger than the size
of the initial balloon, a BUG was triggered as the frames are remaped
beyond the limit of the linear p2m.  The frames are remapped into the
initial balloon area (xen_extra_mem) but not enough of this is
available.

Ensure enough extra memory regions are added for these remapped
frames.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 664dffc..feb6d86 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -366,7 +366,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
 static unsigned long __init xen_set_identity_and_remap_chunk(
         const struct e820entry *list, size_t map_size, unsigned long start_pfn,
        unsigned long end_pfn, unsigned long nr_pages, unsigned long remap_pfn,
-       unsigned long *released)
+       unsigned long *released, unsigned long *remapped)
 {
        unsigned long pfn;
        unsigned long i = 0;
@@ -404,6 +404,7 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
                /* Update variables to reflect new mappings. */
                i += size;
                remap_pfn += size;
+               *remapped += size;
        }
 
        /*
@@ -420,12 +421,13 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 
 static void __init xen_set_identity_and_remap(
        const struct e820entry *list, size_t map_size, unsigned long nr_pages,
-       unsigned long *released)
+       unsigned long *released, unsigned long *remapped)
 {
        phys_addr_t start = 0;
        unsigned long last_pfn = nr_pages;
        const struct e820entry *entry;
        unsigned long num_released = 0;
+       unsigned long num_remapped = 0;
        int i;
 
        /*
@@ -452,12 +454,13 @@ static void __init xen_set_identity_and_remap(
                                last_pfn = xen_set_identity_and_remap_chunk(
                                                list, map_size, start_pfn,
                                                end_pfn, nr_pages, last_pfn,
-                                               &num_released);
+                                               &num_released, &num_remapped);
                        start = end;
                }
        }
 
        *released = num_released;
+       *remapped = num_remapped;
 
        pr_info("Released %ld page(s)\n", num_released);
 }
@@ -577,6 +580,7 @@ char * __init xen_memory_setup(void)
        struct xen_memory_map memmap;
        unsigned long max_pages;
        unsigned long extra_pages = 0;
+       unsigned long remapped_pages;
        int i;
        int op;
 
@@ -626,9 +630,10 @@ char * __init xen_memory_setup(void)
         * underlying RAM.
         */
        xen_set_identity_and_remap(map, memmap.nr_entries, max_pfn,
-                                  &xen_released_pages);
+                                  &xen_released_pages, &remapped_pages);
 
        extra_pages += xen_released_pages;
+       extra_pages += remapped_pages;
 
        /*
         * Clamp the amount of extra memory to a EXTRA_MEM_RATIO