KVM: arm64: Enable GICv3 Group-0 sysreg trapping via command-line

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 <[email protected]> Acked-by: David Daney <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Signed-off-by: Christoffer Dall <[email protected]>
IreneKnapp · Jun 15, 2017 · e23f62f · e23f62f
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commit e23f62f
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diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
@@ -1829,6 +1829,10 @@
 			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

diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
@@ -438,6 +438,12 @@ int vgic_v3_map_resources(struct kvm *kvm)
 
 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);