From 13fc133dd743fa7a96e1b8d7112ca8f1c024e0a5 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Wed, 31 May 2017 18:44:44 +0100
Subject: [PATCH 132/174] arm64: KVM: Preserve RES1 bits in SCTLR_EL2
Git-commit: bae5b3ddb1e7e36cfcc09713ddd73c170493fae2
Patch-mainline: Queued in subsystem maintainer repository
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git kvm-arm-for-v4.12-rc5-take2
References: bsc#1031492
__do_hyp_init has the rather bad habit of ignoring RES1 bits and
writing them back as zero. On a v8.0-8.2 CPU, this doesn't do anything
bad, but may end-up being pretty nasty on future revisions of the
architecture.
Let's preserve those bits so that we don't have to fix this later on.
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/arm64/include/asm/sysreg.h | 4 ++++
arch/arm64/kvm/hyp-init.S | 10 ++++++----
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index f52a4e1..d23ae75 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -286,6 +286,10 @@
#define SCTLR_ELx_A (1 << 1)
#define SCTLR_ELx_M 1
+#define SCTLR_EL2_RES1 ((1 << 4) | (1 << 5) | (1 << 11) | (1 << 16) | \
+ (1 << 16) | (1 << 18) | (1 << 22) | (1 << 23) | \
+ (1 << 28) | (1 << 29))
+
#define SCTLR_ELx_FLAGS (SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C | \
SCTLR_ELx_SA | SCTLR_ELx_I)
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 839425c..4072d40 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -106,10 +106,12 @@ __do_hyp_init:
tlbi alle2
dsb sy
- mrs x4, sctlr_el2
- and x4, x4, #SCTLR_ELx_EE // preserve endianness of EL2
- ldr x5, =SCTLR_ELx_FLAGS
- orr x4, x4, x5
+ /*
+ * Preserve all the RES1 bits while setting the default flags,
+ * as well as the EE bit on BE.
+ */
+ ldr x4, =(SCTLR_EL2_RES1 | SCTLR_ELx_FLAGS)
+CPU_BE( orr x4, x4, #SCTLR_ELx_EE)
msr sctlr_el2, x4
isb
--
1.8.5.6