[Xen-changelog] [xen-unstable] x86: Fix GRANT_PTE_FLAGS.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1225708374 0
# Node ID 4ec25db9326a7e7f64a8471cbfd7b5852484757c
# Parent  540483d2a98f3fbabf06961cc0cc52e3c59c245b
x86: Fix GRANT_PTE_FLAGS.

Since page table entries created through e.g. GNTTABOP_map_grant_ref
are being passed through adjust_guest_l1e(), they must not generally
get _PAGE_USER set - this will be taken care of by adjust_guest_l1e(),
and it will ensure that these don't get _PAGE_GLOBAL set
inadvertently.

Due to the implied security aspect here (_PAGE_GLOBAL getting set on
kernel pages for x86-64), I'd like to ask that this also be applied to
older maintained branches.

At the same time, set _PAGE_NX for pte-s created for grants (as long
as hardware supports it), since it should be only data pages that remote
domains are being given access to.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---
 xen/include/asm-x86/page.h        |    3 +++
 xen/include/asm-x86/x86_32/page.h |    3 ---
 xen/include/asm-x86/x86_64/page.h |    3 ---
 3 files changed, 3 insertions(+), 6 deletions(-)

diff -r 540483d2a98f -r 4ec25db9326a xen/include/asm-x86/page.h
--- a/xen/include/asm-x86/page.h        Mon Nov 03 10:32:02 2008 +0000
+++ b/xen/include/asm-x86/page.h        Mon Nov 03 10:32:54 2008 +0000
@@ -314,6 +314,9 @@ unsigned long clone_idle_pagetable(struc
 #define __PAGE_HYPERVISOR_NOCACHE \
     (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_PCD | _PAGE_ACCESSED)
 
+#define GRANT_PTE_FLAGS \
+    (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_NX | _PAGE_GNTTAB)
+
 #ifndef __ASSEMBLY__
 
 static inline int get_order_from_bytes(paddr_t size)
diff -r 540483d2a98f -r 4ec25db9326a xen/include/asm-x86/x86_32/page.h
--- a/xen/include/asm-x86/x86_32/page.h Mon Nov 03 10:32:02 2008 +0000
+++ b/xen/include/asm-x86/x86_32/page.h Mon Nov 03 10:32:54 2008 +0000
@@ -105,9 +105,6 @@ extern unsigned int PAGE_HYPERVISOR_NOCA
 #define get_pte_flags(x) (((int)((x) >> 32) & ~0xFFF) | ((int)(x) & 0xFFF))
 #define put_pte_flags(x) (((intpte_t)((x) & ~0xFFF) << 32) | ((x) & 0xFFF))
 
-#define GRANT_PTE_FLAGS \
-    (_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_GNTTAB)
-
 /*
  * Disallow unused flag bits plus PAT/PSE, PCD, PWT and GLOBAL.
  * Permit the NX bit if the hardware supports it.
diff -r 540483d2a98f -r 4ec25db9326a xen/include/asm-x86/x86_64/page.h
--- a/xen/include/asm-x86/x86_64/page.h Mon Nov 03 10:32:02 2008 +0000
+++ b/xen/include/asm-x86/x86_64/page.h Mon Nov 03 10:32:54 2008 +0000
@@ -124,9 +124,6 @@ typedef l4_pgentry_t root_pgentry_t;
 #define PAGE_HYPERVISOR         (__PAGE_HYPERVISOR         | _PAGE_GLOBAL)
 #define PAGE_HYPERVISOR_NOCACHE (__PAGE_HYPERVISOR_NOCACHE | _PAGE_GLOBAL)
 
-#define GRANT_PTE_FLAGS \
-    (_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_GNTTAB|_PAGE_USER)
-
 #define USER_MAPPINGS_ARE_GLOBAL
 #ifdef USER_MAPPINGS_ARE_GLOBAL
 /*

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