[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@xensource.com>

diff --git a/xen/arch/x86/x86_32/mm.c b/xen/arch/x86/x86_32/mm.c
index cc438a701741d5eed641afb060051b3e9cda4596..868140e586f5fb4f2de8844fd32aab8abf655810 100644 (file)
--- a/xen/arch/x86/x86_32/mm.c
+++ b/xen/arch/x86/x86_32/mm.c
@@ -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 --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index 87ff181b82056b9c1f182954dd6777e29d39a43d..1379be6f1e0242d0f95d8148e3f8d019b87cb190 100644 (file)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -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);
     }