Re: [PATCH v7 02/17] KVM: arm/arm64: check return value for kvm_register_vgic_device

[Auger Eric <eric.auger@redhat.com>]

On 28/06/2016 14:32, Andre Przywara wrote:
> kvm_register_device_ops() can return an error, so lets check its return
returned
> value and propagate this up the call chain.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  virt/kvm/arm/vgic/vgic-kvm-device.c | 15 +++++++++------
>  virt/kvm/arm/vgic/vgic-v2.c         |  7 ++++++-
>  virt/kvm/arm/vgic/vgic-v3.c         | 15 +++++++++++++--
>  virt/kvm/arm/vgic/vgic.h            |  2 +-
>  4 files changed, 29 insertions(+), 10 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 0130c4b..2f24f13 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -210,20 +210,24 @@ static void vgic_destroy(struct kvm_device *dev)
>  	kfree(dev);
>  }
>  
> -void kvm_register_vgic_device(unsigned long type)
> +int kvm_register_vgic_device(unsigned long type)
>  {
> +	int ret = -ENODEV;
> +
>  	switch (type) {
>  	case KVM_DEV_TYPE_ARM_VGIC_V2:
> -		kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
> -					KVM_DEV_TYPE_ARM_VGIC_V2);
> +		ret = kvm_register_device_ops(&kvm_arm_vgic_v2_ops,
> +					      KVM_DEV_TYPE_ARM_VGIC_V2);
>  		break;
>  #ifdef CONFIG_KVM_ARM_VGIC_V3
>  	case KVM_DEV_TYPE_ARM_VGIC_V3:
> -		kvm_register_device_ops(&kvm_arm_vgic_v3_ops,
> -					KVM_DEV_TYPE_ARM_VGIC_V3);
> +		ret = kvm_register_device_ops(&kvm_arm_vgic_v3_ops,
> +					      KVM_DEV_TYPE_ARM_VGIC_V3);
>  		break;
>  #endif
>  	}
> +
> +	return ret;
>  }
>  
>  /** vgic_attr_regs_access: allows user space to read/write VGIC registers
> @@ -428,4 +432,3 @@ struct kvm_device_ops kvm_arm_vgic_v3_ops = {
>  };
>  
>  #endif /* CONFIG_KVM_ARM_VGIC_V3 */
> -
> diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
> index e31405e..80313de 100644
> --- a/virt/kvm/arm/vgic/vgic-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-v2.c
> @@ -344,7 +344,12 @@ int vgic_v2_probe(const struct gic_kvm_info *info)
>  	}
>  
>  	kvm_vgic_global_state.can_emulate_gicv2 = true;
> -	kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
> +	ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
> +	if (ret) {
> +		kvm_err("Cannot register GICv2 KVM device\n");
> +		iounmap(kvm_vgic_global_state.vctrl_base);
Aren't we supposed to tear down things done in create_hyp_io_mapping
(such as pud_alloc_one)?

Eric
> +		return ret;
> +	}
>  
>  	kvm_vgic_global_state.vcpu_base = info->vcpu.start;
>  	kvm_vgic_global_state.type = VGIC_V2;
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index 346b4ad..e48a22e 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -296,6 +296,7 @@ out:
>  int vgic_v3_probe(const struct gic_kvm_info *info)
>  {
>  	u32 ich_vtr_el2 = kvm_call_hyp(__vgic_v3_get_ich_vtr_el2);
> +	int ret;
>  
>  	/*
>  	 * The ListRegs field is 5 bits, but there is a architectural
> @@ -319,12 +320,22 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
>  	} else {
>  		kvm_vgic_global_state.vcpu_base = info->vcpu.start;
>  		kvm_vgic_global_state.can_emulate_gicv2 = true;
> -		kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
> +		ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
> +		if (ret) {
> +			kvm_err("Cannot register GICv2 KVM device.\n");
> +			return ret;
> +		}
>  		kvm_info("vgic-v2@%llx\n", info->vcpu.start);
>  	}
> +	ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V3);
> +	if (ret) {
> +		kvm_err("Cannot register GICv3 KVM device.\n");
> +		kvm_unregister_device_ops(KVM_DEV_TYPE_ARM_VGIC_V2);
> +		return ret;
> +	}
> +
>  	if (kvm_vgic_global_state.vcpu_base == 0)
>  		kvm_info("disabling GICv2 emulation\n");
> -	kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V3);
>  
>  	kvm_vgic_global_state.vctrl_base = NULL;
>  	kvm_vgic_global_state.type = VGIC_V3;
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 7b300ca..c752152 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -124,7 +124,7 @@ static inline int vgic_register_redist_iodevs(struct kvm *kvm,
>  }
>  #endif
>  
> -void kvm_register_vgic_device(unsigned long type);
> +int kvm_register_vgic_device(unsigned long type);
>  int vgic_lazy_init(struct kvm *kvm);
>  int vgic_init(struct kvm *kvm);
>  
>