[Xen-changelog] [xen-unstable] [HVM] Ensure the read-only M2P table is mapped without _PAGE_GLOBAL

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

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Node ID f437295526037a468bbd2659935ab7935262a99e
# Parent  b26bf72514aa793453d426ccdf888f577c6efd91
[HVM] Ensure the read-only M2P table is mapped without _PAGE_GLOBAL
otherwise context switch to shadow-mode-translate guests does not
work properly (they reuse that area of virtual address space).
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 xen/arch/x86/x86_32/mm.c |    1 +
 xen/arch/x86/x86_64/mm.c |    3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff -r b26bf72514aa -r f43729552603 xen/arch/x86/x86_32/mm.c
--- a/xen/arch/x86/x86_32/mm.c  Tue Aug 15 16:17:24 2006 +0100
+++ b/xen/arch/x86/x86_32/mm.c  Tue Aug 15 16:21:12 2006 +0100
@@ -104,6 +104,7 @@ void __init paging_init(void)
             panic("Not enough memory to bootstrap Xen.\n");
         idle_pg_table_l2[l2_linear_offset(RDWR_MPT_VIRT_START) + i] =
             l2e_from_page(pg, PAGE_HYPERVISOR | _PAGE_PSE);
+        /* NB. Cannot be GLOBAL as shadow_mode_translate reuses this area. */
         idle_pg_table_l2[l2_linear_offset(RO_MPT_VIRT_START) + i] =
             l2e_from_page(pg, (__PAGE_HYPERVISOR | _PAGE_PSE) & ~_PAGE_RW);
     }
diff -r b26bf72514aa -r f43729552603 xen/arch/x86/x86_64/mm.c
--- a/xen/arch/x86/x86_64/mm.c  Tue Aug 15 16:17:24 2006 +0100
+++ b/xen/arch/x86/x86_64/mm.c  Tue Aug 15 16:21:12 2006 +0100
@@ -113,8 +113,9 @@ void __init paging_init(void)
             PAGE_HYPERVISOR);
         memset((void *)(RDWR_MPT_VIRT_START + (i << L2_PAGETABLE_SHIFT)), 0x55,
                1UL << L2_PAGETABLE_SHIFT);
+        /* NB. Cannot be GLOBAL as shadow_mode_translate reuses this area. */
         *l2_ro_mpt++ = l2e_from_page(
-            pg, _PAGE_GLOBAL|_PAGE_PSE|_PAGE_USER|_PAGE_PRESENT);
+            pg, /*_PAGE_GLOBAL|*/_PAGE_PSE|_PAGE_USER|_PAGE_PRESENT);
         BUG_ON(((unsigned long)l2_ro_mpt & ~PAGE_MASK) == 0);
     }
 

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