Patch "arm: KVM: Allow unaligned accesses at HYP" has been added to the 4.11-stable tree

Patch "arm: KVM: Allow unaligned accesses at HYP" has been added to the 4.11-stable tree

[gregkh]

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 4.11-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-4.11 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 33b5c38852b29736f3b472dd095c9a18ec22746f Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Tue, 6 Jun 2017 19:08:35 +0100
Subject: arm: KVM: Allow unaligned accesses at HYP

From: Marc Zyngier <marc.zyngier@arm.com>

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@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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@arm.com are

queue-4.11/arm64-kvm-allow-unaligned-accesses-at-el2.patch
queue-4.11/arm-kvm-allow-unaligned-accesses-at-hyp.patch
queue-4.11/arm64-kvm-preserve-res1-bits-in-sctlr_el2.patch