Patch "x86/kaiser: Move feature detection up" has been added to the 4.4-stable tree

Patch "x86/kaiser: Move feature detection up" has been added to the 4.4-stable tree

[gregkh]

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

    x86/kaiser: Move feature detection up

to the 4.4-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-kaiser-move-feature-detection-up.patch
and it can be found in the queue-4.4 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 foo@baz Wed Jan  3 18:58:12 CET 2018
From: Borislav Petkov <bp@suse.de>
Date: Mon, 25 Dec 2017 13:57:16 +0100
Subject: x86/kaiser: Move feature detection up

From: Borislav Petkov <bp@suse.de>


... before the first use of kaiser_enabled as otherwise funky
things happen:

  about to get started...
  (XEN) d0v0 Unhandled page fault fault/trap [#14, ec=0000]
  (XEN) Pagetable walk from ffff88022a449090:
  (XEN)  L4[0x110] = 0000000229e0e067 0000000000001e0e
  (XEN)  L3[0x008] = 0000000000000000 ffffffffffffffff
  (XEN) domain_crash_sync called from entry.S: fault at ffff82d08033fd08
  entry.o#create_bounce_frame+0x135/0x14d
  (XEN) Domain 0 (vcpu#0) crashed on cpu#0:
  (XEN) ----[ Xen-4.9.1_02-3.21  x86_64  debug=n   Not tainted ]----
  (XEN) CPU:    0
  (XEN) RIP:    e033:[<ffffffff81007460>]
  (XEN) RFLAGS: 0000000000000286   EM: 1   CONTEXT: pv guest (d0v0)

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/include/asm/kaiser.h |    2 ++
 arch/x86/kernel/setup.c       |    7 +++++++
 arch/x86/mm/kaiser.c          |    2 --
 3 files changed, 9 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -96,8 +96,10 @@ DECLARE_PER_CPU(unsigned long, x86_cr3_p
 extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
 
 extern int kaiser_enabled;
+extern void __init kaiser_check_boottime_disable(void);
 #else
 #define kaiser_enabled	0
+static inline void __init kaiser_check_boottime_disable(void) {}
 #endif /* CONFIG_KAISER */
 
 /*
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -112,6 +112,7 @@
 #include <asm/alternative.h>
 #include <asm/prom.h>
 #include <asm/microcode.h>
+#include <asm/kaiser.h>
 
 /*
  * max_low_pfn_mapped: highest direct mapped pfn under 4GB
@@ -1016,6 +1017,12 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	init_hypervisor_platform();
 
+	/*
+	 * This needs to happen right after XENPV is set on xen and
+	 * kaiser_enabled is checked below in cleanup_highmap().
+	 */
+	kaiser_check_boottime_disable();
+
 	x86_init.resources.probe_roms();
 
 	/* after parse_early_param, so could debug it */
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -311,8 +311,6 @@ void __init kaiser_init(void)
 {
 	int cpu;
 
-	kaiser_check_boottime_disable();
-
 	if (!kaiser_enabled)
 		return;
 


Patches currently in stable-queue which might be from bp@suse.de are

queue-4.4/x86-paravirt-dont-patch-flush_tlb_single.patch
queue-4.4/x86-kaiser-reenable-paravirt.patch
queue-4.4/x86-kaiser-rename-and-simplify-x86_feature_kaiser-handling.patch
queue-4.4/x86-kaiser-check-boottime-cmdline-params.patch
queue-4.4/x86-kaiser-move-feature-detection-up.patch