Patch "x86/vsyscall/64: Use proper accessor to update P4D entry" has been added to the 4.15-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    x86/vsyscall/64: Use proper accessor to update P4D entry

to the 4.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-vsyscall-64-use-proper-accessor-to-update-p4d-entry.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 31ad7f8e7dc94d3b85ccf9b6141ce6dfd35a1781 Mon Sep 17 00:00:00 2001
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Date: Mon, 19 Mar 2018 10:31:54 -0400
Subject: x86/vsyscall/64: Use proper accessor to update P4D entry

From: Boris Ostrovsky <boris.ostrovsky@oracle.com>

commit 31ad7f8e7dc94d3b85ccf9b6141ce6dfd35a1781 upstream.

Writing to it directly does not work for Xen PV guests.

Fixes: 49275fef986a ("x86/vsyscall/64: Explicitly set _PAGE_USER in the pagetable hierarchy")
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180319143154.3742-1-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/entry/vsyscall/vsyscall_64.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -355,7 +355,7 @@ void __init set_vsyscall_pgtable_user_bi
 	set_pgd(pgd, __pgd(pgd_val(*pgd) | _PAGE_USER));
 	p4d = p4d_offset(pgd, VSYSCALL_ADDR);
 #if CONFIG_PGTABLE_LEVELS >= 5
-	p4d->p4d |= _PAGE_USER;
+	set_p4d(p4d, __p4d(p4d_val(*p4d) | _PAGE_USER));
 #endif
 	pud = pud_offset(p4d, VSYSCALL_ADDR);
 	set_pud(pud, __pud(pud_val(*pud) | _PAGE_USER));


Patches currently in stable-queue which might be from boris.ostrovsky@oracle.com are

queue-4.15/x86-vsyscall-64-use-proper-accessor-to-update-p4d-entry.patch