[Xen-changelog] [xen-unstable] x86-64: properly handle alias mappings beyond _end

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxxxx>
# Date 1310631973 -3600
# Node ID 80c9db90bba96e443a22d268c06948fdef9c6a75
# Parent  88823213a4780ebced6d7adcb1ffd2dda6a339ca
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@xxxxxxxxxx>
---


diff -r 88823213a478 -r 80c9db90bba9 xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Fri Jul 08 13:23:05 2011 +0100
+++ b/xen/arch/x86/mm.c Thu Jul 14 09:26:13 2011 +0100
@@ -805,7 +805,7 @@
     int err = 0;
 #ifdef __x86_64__
     bool_t alias = mfn >= PFN_DOWN(xen_phys_start) &&
-         mfn < PFN_UP(xen_phys_start + (unsigned long)_end - XEN_VIRT_START);
+         mfn < PFN_UP(xen_phys_start + xen_virt_end - XEN_VIRT_START);
     unsigned long xen_va =
         XEN_VIRT_START + ((mfn - PFN_DOWN(xen_phys_start)) << PAGE_SHIFT);
 
diff -r 88823213a478 -r 80c9db90bba9 xen/arch/x86/setup.c
--- a/xen/arch/x86/setup.c      Fri Jul 08 13:23:05 2011 +0100
+++ b/xen/arch/x86/setup.c      Thu Jul 14 09:26:13 2011 +0100
@@ -94,6 +94,8 @@
 /* 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 @@
     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();
diff -r 88823213a478 -r 80c9db90bba9 xen/include/asm-x86/x86_64/page.h
--- a/xen/include/asm-x86/x86_64/page.h Fri Jul 08 13:23:05 2011 +0100
+++ b/xen/include/asm-x86/x86_64/page.h Thu Jul 14 09:26:13 2011 +0100
@@ -35,6 +35,8 @@
 #include <xen/config.h>
 #include <asm/types.h>
 
+extern unsigned long xen_virt_end;
+
 extern unsigned long max_pdx;
 extern unsigned long pfn_pdx_bottom_mask, ma_va_bottom_mask;
 extern unsigned int pfn_pdx_hole_shift;

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