From 83abf705f67b2e45fb6b810f88045b9a727488f8 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 9 Jun 2017 12:49:41 +0100
Subject: [PATCH 159/174] KVM: arm64: Enable GICv3 Group-1 sysreg trapping via
command-line
Patch-mainline: Submitted, https://www.spinics.net/lists/arm-kernel/msg587082.html
References: bsc#1031492
Now that we're able to safely handle Group-1 sysreg access, let's
give the user the opportunity to enable it by passing a specific
command-line option (vgic_v3.group1_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: Alexander Graf <agraf@suse.de>
---
virt/kvm/arm/vgic/vgic-v3.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 722bdeb..4b2b62b 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -435,6 +435,12 @@ out:
DEFINE_STATIC_KEY_FALSE(vgic_v3_cpuif_trap);
+static int __init early_group1_trap_cfg(char *buf)
+{
+ return strtobool(buf, &group1_trap);
+}
+early_param("kvm-arm.vgic_v3_group1_trap", early_group1_trap_cfg);
+
/**
* vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
* @node: pointer to the DT node
@@ -486,6 +492,11 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
if (kvm_vgic_global_state.vcpu_base == 0)
kvm_info("disabling GICv2 emulation\n");
+ if (group1_trap) {
+ kvm_info("GICv3 sysreg trapping enabled (reduced performance)\n");
+ static_branch_enable(&vgic_v3_cpuif_trap);
+ }
+
kvm_vgic_global_state.vctrl_base = NULL;
kvm_vgic_global_state.type = VGIC_V3;
kvm_vgic_global_state.max_gic_vcpus = VGIC_V3_MAX_CPUS;
--
1.8.5.6