Patch "x86/cpufeatures: Add X86_BUG_CPU_INSECURE" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    x86/cpufeatures: Add X86_BUG_CPU_INSECURE

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-cpufeatures-add-x86_bug_cpu_insecure.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 a89f040fa34ec9cd682aed98b8f04e3c47d998bd Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 4 Dec 2017 15:07:33 +0100
Subject: x86/cpufeatures: Add X86_BUG_CPU_INSECURE

From: Thomas Gleixner <tglx@linutronix.de>

commit a89f040fa34ec9cd682aed98b8f04e3c47d998bd upstream.

Many x86 CPUs leak information to user space due to missing isolation of
user space and kernel space page tables. There are many well documented
ways to exploit that.

The upcoming software migitation of isolating the user and kernel space
page tables needs a misfeature flag so code can be made runtime
conditional.

Add the BUG bits which indicates that the CPU is affected and add a feature
bit which indicates that the software migitation is enabled.

Assume for now that _ALL_ x86 CPUs are affected by this. Exceptions can be
made later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/include/asm/cpufeature.h |    1 +
 arch/x86/kernel/cpu/common.c      |    4 ++++
 2 files changed, 5 insertions(+)

--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -277,6 +277,7 @@
 #define X86_BUG_FXSAVE_LEAK	X86_BUG(6) /* FXSAVE leaks FOP/FIP/FOP */
 #define X86_BUG_CLFLUSH_MONITOR	X86_BUG(7) /* AAI65, CLFLUSH required before MONITOR */
 #define X86_BUG_SYSRET_SS_ATTRS	X86_BUG(8) /* SYSRET doesn't fix up SS attrs */
+#define X86_BUG_CPU_INSECURE	X86_BUG(14) /* CPU is insecure and needs kernel page table isolation */
 
 #if defined(__KERNEL__) && !defined(__ASSEMBLY__)
 
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -830,6 +830,10 @@ static void __init early_identify_cpu(st
 	}
 
 	setup_force_cpu_cap(X86_FEATURE_ALWAYS);
+
+	/* Assume for now that ALL x86 CPUs are insecure */
+	setup_force_cpu_bug(X86_BUG_CPU_INSECURE);
+
 	fpu__init_system(c);
 }
 


Patches currently in stable-queue which might be from tglx@linutronix.de are

queue-4.4/x86-mm-pat-dev-mem-remove-superfluous-error-message.patch
queue-4.4/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.4/x86-microcode-intel-extend-bdw-late-loading-with-a-revision-check.patch
queue-4.4/x86-alternatives-add-missing-n-at-end-of-alternative-inline-asm.patch
queue-4.4/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.4/locking-mutex-allow-next-waiter-lockless-wakeup.patch
queue-4.4/x86-cpufeatures-add-x86_bug_cpu_insecure.patch
queue-4.4/x86-cpufeatures-make-cpu-bugs-sticky.patch
queue-4.4/x86-vsdo-fix-build-on-paravirt_clock-y-kvm_guest-n.patch
queue-4.4/x86-pti-efi-broken-conversion-from-efi-to-kernel-page-table.patch
queue-4.4/x86-documentation-add-pti-description.patch
queue-4.4/x86-acpi-handle-sci-interrupts-above-legacy-space-gracefully.patch
queue-4.4/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.4/futex-replace-barrier-in-unqueue_me-with-read_once.patch
queue-4.4/x86-cpu-factor-out-application-of-forced-cpu-caps.patch
queue-4.4/selftests-x86-add-test_vsyscall.patch
queue-4.4/x86-cpu-merge-bugs.c-and-bugs_64.c.patch
queue-4.4/sysfs-cpu-add-vulnerability-folder.patch
queue-4.4/x86-pti-rename-bug_cpu_insecure-to-bug_cpu_meltdown.patch
queue-4.4/x86-acpi-reduce-code-duplication-in-mp_override_legacy_irq.patch
queue-4.4/x86-alternatives-fix-optimize_nops-checking.patch