[PATCH 4.17 49/67] xen: remove global bit from __default_kernel_pte_mask for pv guests

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Juergen Gross <jgross@xxxxxxxx>

commit e69b5d308da72cbf4e7911c3979f9a46d28532af upstream.

When removing the global bit from __supported_pte_mask do the same for
__default_kernel_pte_mask in order to avoid the WARN_ONCE() in
check_pgprot() when setting a kernel pte before having called
init_mem_mapping().

Cc: <stable@xxxxxxxxxxxxxxx> # 4.17
Reported-by: Michael Young <m.a.young@xxxxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/xen/enlighten_pv.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1228,6 +1228,7 @@ asmlinkage __visible void __init xen_sta
 
 	/* Prevent unwanted bits from being set in PTEs. */
 	__supported_pte_mask &= ~_PAGE_GLOBAL;
+	__default_kernel_pte_mask &= ~_PAGE_GLOBAL;
 
 	/*
 	 * Prevent page tables from being allocated in highmem, even