From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 9 Jun 2017 12:49:46 +0100
Subject: KVM: arm64: Enable GICv3 Group-0 sysreg trapping via command-line
Patch-mainline: v4.13-rc1
Git-commit: e23f62f76acea232d4def5d4eb21709a2b575f14
References: bsc#1077761

Now that we're able to safely handle Group-0 sysreg access, let's
give the user the opportunity to enable it by passing a specific
command-line option (vgic_v3.group0_trap).

Tested-by: Alexander Graf <agraf@suse.de>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Acked-by: Alexander Graf <agraf@suse.de>
---
 Documentation/admin-guide/kernel-parameters.txt |    4 ++++
 virt/kvm/arm/vgic/vgic-v3.c                     |    6 ++++++
 2 files changed, 10 insertions(+)

--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1838,6 +1838,10 @@
 			for all guests.
 			Default is 1 (enabled) if in 64-bit or 32-bit PAE mode.
 
+	kvm-arm.vgic_v3_group0_trap=
+			[KVM,ARM] Trap guest accesses to GICv3 group-0
+			system registers
+
 	kvm-arm.vgic_v3_group1_trap=
 			[KVM,ARM] Trap guest accesses to GICv3 group-1
 			system registers
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -438,6 +438,12 @@
 
 DEFINE_STATIC_KEY_FALSE(vgic_v3_cpuif_trap);
 
+static int __init early_group0_trap_cfg(char *buf)
+{
+	return strtobool(buf, &group0_trap);
+}
+early_param("kvm-arm.vgic_v3_group0_trap", early_group0_trap_cfg);
+
 static int __init early_group1_trap_cfg(char *buf)
 {
 	return strtobool(buf, &group1_trap);