KPTI Fix

kernel.spec

@@ -42,7 +42,7 @@ Summary: The Linux kernel
 # For non-released -rc kernels, this will be appended after the rcX and
 # gitX tags, so a 3 here would become part of release "0.rcX.gitX.3"
 #
-%global baserelease 1
+%global baserelease 2
 %global fedora_build %{baserelease}
 
 # base_sublevel is the kernel version we're starting with and patching
@@ -647,6 +647,9 @@ Patch636: 0001-ahci-Annotate-PCI-ids-for-mobile-Intel-chipsets-as-s.patch
 Patch637: 0002-ahci-Add-PCI-ids-for-Intel-Bay-Trail-Cherry-Trail-an.patch
 Patch638: 0003-ahci-Allow-setting-a-default-LPM-policy-for-mobile-c.patch
 
+# KPTI Fixups
+Patch639: kpti-fix.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -2198,6 +2201,9 @@ fi
 #
 #
 %changelog
+* Wed Jan 03 2018 Laura Abbott <labbott@redhat.com> - 4.15.0-0.rc6.git0.2
+- KPTI Fix
+
 * Mon Jan 01 2018 Laura Abbott <labbott@redhat.com> - 4.15.0-0.rc6.git0.1
 - Linux v4.15-rc6
 

kpti-fix.patch

@@ -0,0 +1,56 @@
+From 52994c256df36fda9a715697431cba9daecb6b11 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 3 Jan 2018 15:57:59 +0100
+Subject: x86/pti: Make sure the user/kernel PTEs match
+
+Meelis reported that his K8 Athlon64 emits MCE warnings when PTI is
+enabled:
+
+[Hardware Error]: Error Addr: 0x0000ffff81e000e0
+[Hardware Error]: MC1 Error: L1 TLB multimatch.
+[Hardware Error]: cache level: L1, tx: INSN
+
+The address is in the entry area, which is mapped into kernel _AND_ user
+space. That's special because we switch CR3 while we are executing
+there.
+
+User mapping:
+0xffffffff81e00000-0xffffffff82000000           2M     ro         PSE     GLB x  pmd
+
+Kernel mapping:
+0xffffffff81000000-0xffffffff82000000          16M     ro         PSE         x  pmd
+
+So the K8 is complaining that the TLB entries differ. They differ in the
+GLB bit.
+
+Drop the GLB bit when installing the user shared mapping.
+
+Fixes: 6dc72c3cbca0 ("x86/mm/pti: Share entry text PMD")
+Reported-by: Meelis Roos <mroos@linux.ee>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Meelis Roos <mroos@linux.ee>
+Cc: Borislav Petkov <bp@alien8.de>
+Cc: Tom Lendacky <thomas.lendacky@amd.com>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801031407180.1957@nanos
+---
+ arch/x86/mm/pti.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
+index bce8aea..2da28ba 100644
+--- a/arch/x86/mm/pti.c
++++ b/arch/x86/mm/pti.c
+@@ -367,7 +367,8 @@ static void __init pti_setup_espfix64(void)
+ static void __init pti_clone_entry_text(void)
+ {
+ 	pti_clone_pmds((unsigned long) __entry_text_start,
+-			(unsigned long) __irqentry_text_end, _PAGE_RW);
++			(unsigned long) __irqentry_text_end,
++		       _PAGE_RW | _PAGE_GLOBAL);
+ }
+ 
+ /*
+-- 
+cgit v1.1
+