KVM: arm/arm64: vgic: Don't flush/sync without a working vgic

If the vgic hasn't been created and initialized, we shouldn't attempt to
look at its data structures or flush/sync anything to the GIC hardware.

This fixes an issue reported by Alexander Graf when using a userspace
irqchip.

Fixes: 0919e84c0fc1 ("KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework")
Cc: stable@vger.kernel.org
Reported-by: Alexander Graf <agraf@suse.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 8a529a732941..2893d5ba523a 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -645,6 +645,9 @@ next:
 /* Sync back the hardware VGIC state into our emulation after a guest's run. */
 void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 {
+        if (unlikely(!vgic_initialized(vcpu->kvm)))
+                return;
+
         vgic_process_maintenance_interrupt(vcpu);
         vgic_fold_lr_state(vcpu);
         vgic_prune_ap_list(vcpu);
@@ -653,6 +656,9 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 /* Flush our emulation state into the GIC hardware before entering the guest. */
 void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 {
+        if (unlikely(!vgic_initialized(vcpu->kvm)))
+                return;
+
         spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
         vgic_flush_lr_state(vcpu);
         spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);