KVM: arm/arm64: GICv4: Enable VLPI support

All it takes is the has_v4 flag to be set in gic_kvm_info
as well as "kvm-arm.vgic_v4_enable=1" being passed on the
command line for GICv4 to be enabled in KVM.

Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

2 files changed, 18 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 3daa0a590236..6f897a4c8281 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1881,6 +1881,10 @@
                         [KVM,ARM] Trap guest accesses to GICv3 common
                         system registers
 
+        kvm-arm.vgic_v4_enable=
+                        [KVM,ARM] Allow use of GICv4 for direct injection of
+                        LPIs.
+
         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 863351c090d8..2f05f732d3fd 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -24,6 +24,7 @@
 static bool group0_trap;
 static bool group1_trap;
 static bool common_trap;
+static bool gicv4_enable;
 
 void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
 {
@@ -461,6 +462,12 @@ static int __init early_common_trap_cfg(char *buf)
 }
 early_param("kvm-arm.vgic_v3_common_trap", early_common_trap_cfg);
 
+static int __init early_gicv4_enable(char *buf)
+{
+        return strtobool(buf, &gicv4_enable);
+}
+early_param("kvm-arm.vgic_v4_enable", early_gicv4_enable);
+
 /**
  * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
  * @node:       pointer to the DT node
@@ -480,6 +487,13 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
         kvm_vgic_global_state.can_emulate_gicv2 = false;
         kvm_vgic_global_state.ich_vtr_el2 = ich_vtr_el2;
 
+        /* GICv4 support? */
+        if (info->has_v4) {
+                kvm_vgic_global_state.has_gicv4 = gicv4_enable;
+                kvm_info("GICv4 support %sabled\n",
+                         gicv4_enable ? "en" : "dis");
+        }
+
         if (!info->vcpu.start) {
                 kvm_info("GICv3: no GICV resource entry\n");
                 kvm_vgic_global_state.vcpu_base = 0;