patches/kernel/0076-x86-xen-Provide-pre-built-page-tables-only-for-CONFI.patch

   1 From cac8711a9ba742e97090cc5ec522360f1549c584 Mon Sep 17 00:00:00 2001
   2 From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
   3 Date: Fri, 29 Sep 2017 17:08:19 +0300
   4 Subject: [PATCH 076/233] x86/xen: Provide pre-built page tables only for
   5  CONFIG_XEN_PV=y and CONFIG_XEN_PVH=y
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 CVE-2017-5754
  11
  12 Looks like we only need pre-built page tables in the CONFIG_XEN_PV=y and
  13 CONFIG_XEN_PVH=y cases.
  14
  15 Let's not provide them for other configurations.
  16
  17 Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
  18 Reviewed-by: Juergen Gross <jgross@suse.com>
  19 Cc: Andrew Morton <akpm@linux-foundation.org>
  20 Cc: Andy Lutomirski <luto@amacapital.net>
  21 Cc: Borislav Petkov <bp@suse.de>
  22 Cc: Cyrill Gorcunov <gorcunov@openvz.org>
  23 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  24 Cc: Peter Zijlstra <peterz@infradead.org>
  25 Cc: Thomas Gleixner <tglx@linutronix.de>
  26 Cc: linux-mm@kvack.org
  27 Link: http://lkml.kernel.org/r/20170929140821.37654-5-kirill.shutemov@linux.intel.com
  28 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  29 (cherry picked from commit 4375c29985f155d7eb2346615d84e62d1b673682)
  30 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  31 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  32 (cherry picked from commit a883ee7f3c1dc64a8c946543ac598399353d1b03)
  33 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  34 ---
  35  arch/x86/kernel/head_64.S | 11 ++++++-----
  36  1 file changed, 6 insertions(+), 5 deletions(-)
  37
  38 diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
  39 index d081bc7a027d..12daaa0b187f 100644
  40 --- a/arch/x86/kernel/head_64.S
  41 +++ b/arch/x86/kernel/head_64.S
  42 @@ -37,11 +37,12 @@
  43   *
  44   */
  45
  46 -#define p4d_index(x)   (((x) >> P4D_SHIFT) & (PTRS_PER_P4D-1))
  47  #define pud_index(x)   (((x) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
  48
  49 +#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
  50  PGD_PAGE_OFFSET = pgd_index(__PAGE_OFFSET_BASE)
  51  PGD_START_KERNEL = pgd_index(__START_KERNEL_map)
  52 +#endif
  53  L3_START_KERNEL = pud_index(__START_KERNEL_map)
  54
  55         .text
  56 @@ -348,10 +349,7 @@ NEXT_PAGE(early_dynamic_pgts)
  57
  58         .data
  59
  60 -#ifndef CONFIG_XEN
  61 -NEXT_PAGE(init_top_pgt)
  62 -       .fill   512,8,0
  63 -#else
  64 +#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
  65  NEXT_PAGE(init_top_pgt)
  66         .quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
  67         .org    init_top_pgt + PGD_PAGE_OFFSET*8, 0
  68 @@ -368,6 +366,9 @@ NEXT_PAGE(level2_ident_pgt)
  69          * Don't set NX because code runs from these pages.
  70          */
  71         PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
  72 +#else
  73 +NEXT_PAGE(init_top_pgt)
  74 +       .fill   512,8,0
  75  #endif
  76
  77  #ifdef CONFIG_X86_5LEVEL
  78 --
  79 2.14.2
  80