This is a note to let you know that I've just added the patch titled
arm: KVM: Allow unaligned accesses at HYP
to the 4.9-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:
arm-kvm-allow-unaligned-accesses-at-hyp.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 33b5c38852b29736f3b472dd095c9a18ec22746f Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@xxxxxxx>
Date: Tue, 6 Jun 2017 19:08:35 +0100
Subject: arm: KVM: Allow unaligned accesses at HYP
From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit 33b5c38852b29736f3b472dd095c9a18ec22746f upstream.
We currently have the HSCTLR.A bit set, trapping unaligned accesses
at HYP, but we're not really prepared to deal with it.
Since the rest of the kernel is pretty happy about that, let's follow
its example and set HSCTLR.A to zero. Modern CPUs don't really care.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <cdall@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/kvm/init.S | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -95,7 +95,6 @@ __do_hyp_init:
@ - Write permission implies XN: disabled
@ - Instruction cache: enabled
@ - Data/Unified cache: enabled
- @ - Memory alignment checks: enabled
@ - MMU: enabled (this code must be run from an identity mapping)
mrc p15, 4, r0, c1, c0, 0 @ HSCR
ldr r2, =HSCTLR_MASK
@@ -103,8 +102,8 @@ __do_hyp_init:
mrc p15, 0, r1, c1, c0, 0 @ SCTLR
ldr r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C)
and r1, r1, r2
- ARM( ldr r2, =(HSCTLR_M | HSCTLR_A) )
- THUMB( ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) )
+ ARM( ldr r2, =(HSCTLR_M) )
+ THUMB( ldr r2, =(HSCTLR_M | HSCTLR_TE) )
orr r1, r1, r2
orr r0, r0, r1
mcr p15, 4, r0, c1, c0, 0 @ HSCR
Patches currently in stable-queue which might be from marc.zyngier@xxxxxxx are
queue-4.9/arm64-kvm-allow-unaligned-accesses-at-el2.patch
queue-4.9/arm-kvm-allow-unaligned-accesses-at-hyp.patch
queue-4.9/arm64-kvm-preserve-res1-bits-in-sctlr_el2.patch