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@xxxxxxx>
Acked-by: David Daney <david.daney@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Christoffer Dall <cdall@xxxxxxxxxx>
Signed-off-by: Christoffer Dall <cdall@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++++
virt/kvm/arm/vgic/vgic-v3.c | 11 +++++++++++
2 files changed, 15 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 15f79c27748d..42fe395be6c8 100644
--- 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_group1_trap=
+ [KVM,ARM] Trap guest accesses to GICv3 group-1
+ system registers
+
kvm-intel.ept= [KVM,Intel] Disable extended page tables
(virtualized MMU) support on capable Intel chips.
Default is 1 (enabled)
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 722bdebdfbb5..4b2b62b73470 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -435,6 +435,12 @@ int vgic_v3_map_resources(struct kvm *kvm)
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;
--
2.11.0
