[PATCH 4.14 025/159] x86/xen: Provide pre-built page tables only for CONFIG_XEN_PV=y and CONFIG_XEN_PVH=y

Greg Kroah-Hartman
2017-12-22T08:59:16Z

From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

commit 4375c29985f155d7eb2346615d84e62d1b673682 upstream.

Looks like we only need pre-built page tables in the CONFIG_XEN_PV=y and
CONFIG_XEN_PVH=y cases.

Let's not provide them for other configurations.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-5-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kernel/head_64.S | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -38,11 +38,12 @@
*
*/

-#define p4d_index(x) (((x) >> P4D_SHIFT) & (PTRS_PER_P4D-1))
#define pud_index(x) (((x) >> PUD_SHIFT) & (PTRS_PER_PUD-1))

+#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
PGD_PAGE_OFFSET = pgd_index(__PAGE_OFFSET_BASE)
PGD_START_KERNEL = pgd_index(__START_KERNEL_map)
+#endif
L3_START_KERNEL = pud_index(__START_KERNEL_map)

.text
@@ -365,10 +366,7 @@ NEXT_PAGE(early_dynamic_pgts)

.data

-#ifndef CONFIG_XEN
-NEXT_PAGE(init_top_pgt)
- .fill 512,8,0
-#else
+#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
NEXT_PAGE(init_top_pgt)
.quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
.org init_top_pgt + PGD_PAGE_OFFSET*8, 0
@@ -385,6 +383,9 @@ NEXT_PAGE(level2_ident_pgt)
* Don't set NX because code runs from these pages.
*/
PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
+#else
+NEXT_PAGE(init_top_pgt)
+ .fill 512,8,0
#endif

#ifdef CONFIG_X86_5LEVEL