KVM: arm64: vgic: Free private_irqs when init fails after allocation

Companion to commit 250f253 ("KVM: arm64: Tear down vGIC on
failed vCPU creation"), which added the missing kvm_vgic_vcpu_destroy()
call to the kvm_share_hyp() failure path in kvm_arch_vcpu_create(). The
kvm_vgic_vcpu_init() failure path immediately above it has the same
shape and still needs the same cleanup.

Call kvm_vgic_vcpu_destroy() when kvm_vgic_vcpu_init() fails so private
IRQs allocated before a redistributor iodev registration failure are
released before the failed vCPU is freed.

Fixes: 03b3d00 ("KVM: arm64: vgic: Allocate private interrupts on demand")
Cc: stable@vger.kernel.org
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Yuan Yao <yaoyuan@linux.alibaba.com>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://lore.kernel.org/r/20260519135042.2219239-1-michael.bommarito@gmail.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: mjbommar

arch/arm64/kvm/arm.c

@@ -555,8 +555,10 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	kvm_destroy_mpidr_data(vcpu->kvm);
 
 	err = kvm_vgic_vcpu_init(vcpu);
-	if (err)
+	if (err) {
+		kvm_vgic_vcpu_destroy(vcpu);
 		return err;
+	}
 
 	err = kvm_share_hyp(vcpu, vcpu + 1);
 	if (err)