x86-64: properly handle alias mappings beyond _end

Changeset 19632:b0966b6f5180 wasn't really complete: The Xen image
mapping doesn't end at _end, but a full 16Mb gets mapped during boot
(and never got unmapped so far), hence all of this space was subject
to alias mappings when it comes to cache attribute changes. Unmap all
full large pages between _end and the 16Mb boundary, and include all
other pages beyond _end when checking for aliases.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index a7d132a250..c2a2aaab56 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -94,6 +94,8 @@ unsigned long __read_mostly xen_phys_start;
 /* Limits of Xen heap, used to initialise the allocator. */
 unsigned long __initdata xenheap_initial_phys_start;
 unsigned long __read_mostly xenheap_phys_end;
+#else
+unsigned long __read_mostly xen_virt_end;
 #endif
 
 DEFINE_PER_CPU(struct tss_struct, init_tss);
@@ -1094,6 +1096,9 @@ void __init __start_xen(unsigned long mbi_p)
     map_pages_to_xen((unsigned long)__va(kexec_crash_area.start),
                      kexec_crash_area.start >> PAGE_SHIFT,
                      PFN_UP(kexec_crash_area.size), PAGE_HYPERVISOR);
+    xen_virt_end = ((unsigned long)_end + (1UL << L2_PAGETABLE_SHIFT) - 1) &
+                   ~((1UL << L2_PAGETABLE_SHIFT) - 1);
+    destroy_xen_mappings(xen_virt_end, XEN_VIRT_START + BOOTSTRAP_MAP_BASE);
 #endif
 
     memguard_init();