Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDavid Vrabel <david.vrabel@citrix.com>2013-08-16 15:42:55 +0100
committerBen Hutchings <ben@decadent.org.uk>2013-09-10 01:57:41 +0100
commit89ca702c526551f4678834ed29eafe824a0ee94b (patch)
tree3d8f77bb2560c32ab0cb0cae716deb9b7e796708
parent13380d4622567edfeb4de4081b93dedb28189a89 (diff)
x86/xen: do not identity map UNUSABLE regions in the machine E820
commit 3bc38cbceb85881a8eb789ee1aa56678038b1909 upstream. If there are UNUSABLE regions in the machine memory map, dom0 will attempt to map them 1:1 which is not permitted by Xen and the kernel will crash. There isn't anything interesting in the UNUSABLE region that the dom0 kernel needs access to so we can avoid making the 1:1 mapping and treat it as RAM. We only do this for dom0, as that is where tboot case shows up. A PV domU could have an UNUSABLE region in its pseudo-physical map and would need to be handled in another patch. This fixes a boot failure on hosts with tboot. tboot marks a region in the e820 map as unusable and the dom0 kernel would attempt to map this region and Xen does not permit unusable regions to be mapped by guests. (XEN) 0000000000000000 - 0000000000060000 (usable) (XEN) 0000000000060000 - 0000000000068000 (reserved) (XEN) 0000000000068000 - 000000000009e000 (usable) (XEN) 0000000000100000 - 0000000000800000 (usable) (XEN) 0000000000800000 - 0000000000972000 (unusable) tboot marked this region as unusable. (XEN) 0000000000972000 - 00000000cf200000 (usable) (XEN) 00000000cf200000 - 00000000cf38f000 (reserved) (XEN) 00000000cf38f000 - 00000000cf3ce000 (ACPI data) (XEN) 00000000cf3ce000 - 00000000d0000000 (reserved) (XEN) 00000000e0000000 - 00000000f0000000 (reserved) (XEN) 00000000fe000000 - 0000000100000000 (reserved) (XEN) 0000000100000000 - 0000000630000000 (usable) Signed-off-by: David Vrabel <david.vrabel@citrix.com> [v1: Altered the patch and description with domU's with UNUSABLE regions] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--arch/x86/xen/setup.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 6e5a7f12081e..4d54b38e310c 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -212,6 +212,17 @@ static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
e820_add_region(start, end - start, type);
}
+void xen_ignore_unusable(struct e820entry *list, size_t map_size)
+{
+ struct e820entry *entry;
+ unsigned int i;
+
+ for (i = 0, entry = list; i < map_size; i++, entry++) {
+ if (entry->type == E820_UNUSABLE)
+ entry->type = E820_RAM;
+ }
+}
+
/**
* machine_specific_memory_setup - Hook for machine specific memory setup.
**/
@@ -250,6 +261,17 @@ char * __init xen_memory_setup(void)
}
BUG_ON(rc);
+ /*
+ * Xen won't allow a 1:1 mapping to be created to UNUSABLE
+ * regions, so if we're using the machine memory map leave the
+ * region as RAM as it is in the pseudo-physical map.
+ *
+ * UNUSABLE regions in domUs are not handled and will need
+ * a patch in the future.
+ */
+ if (xen_initial_domain())
+ xen_ignore_unusable(map, memmap.nr_entries);
+
/* Make sure the Xen-supplied memory map is well-ordered. */
sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);