From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 9 Jun 2017 12:49:45 +0100
Subject: KVM: arm64: vgic-v3: Enable trapping of Group-0 system registers
Patch-mainline: v4.13-rc1
Git-commit: abf55766f7b062234083ff612446ff8d47e2417e
References: bsc#1077761

In order to be able to trap Group-0 GICv3 system registers, we need to
set ICH_HCR_EL2.TALL0 begore entering the guest. This is conditionnaly
done after having restored the guest's state, and cleared on exit.

Tested-by: Alexander Graf <agraf@suse.de>
Acked-by: David Daney <david.daney@cavium.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.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>
---
 include/linux/irqchip/arm-gic-v3.h |    1 +
 virt/kvm/arm/vgic/vgic-v3.c        |    5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -417,6 +417,7 @@
 
 #define ICH_HCR_EN			(1 << 0)
 #define ICH_HCR_UIE			(1 << 1)
+#define ICH_HCR_TALL0			(1 << 11)
 #define ICH_HCR_TALL1			(1 << 12)
 #define ICH_HCR_EOIcount_SHIFT		27
 #define ICH_HCR_EOIcount_MASK		(0x1f << ICH_HCR_EOIcount_SHIFT)
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -21,6 +21,7 @@
 
 #include "vgic.h"
 
+static bool group0_trap;
 static bool group1_trap;
 
 void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
@@ -260,6 +261,8 @@
 
 	/* Get the show on the road... */
 	vgic_v3->vgic_hcr = ICH_HCR_EN;
+	if (group0_trap)
+		vgic_v3->vgic_hcr |= ICH_HCR_TALL0;
 	if (group1_trap)
 		vgic_v3->vgic_hcr |= ICH_HCR_TALL1;
 }
@@ -492,7 +495,7 @@
 	if (kvm_vgic_global_state.vcpu_base == 0)
 		kvm_info("disabling GICv2 emulation\n");
 
-	if (group1_trap) {
+	if (group0_trap || group1_trap) {
 		kvm_info("GICv3 sysreg trapping enabled (reduced performance)\n");
 		static_branch_enable(&vgic_v3_cpuif_trap);
 	}