On 05/08/15 18:07, nick wrote:
>
>
> On 2015-08-05 12:59 PM, Paolo Bonzini wrote:
>>
>>
>> On 05/08/2015 18:48, Nicholas Krause wrote:
>>> This fixes the error handling in the function vgic_v3_probe
>>> for when calling the function kvm_register_device_ops to check
>>> if the call to this function has returned a error code and if
>>> so jump to the label out with goto to cleanup no longer required
>>> resources used by the function vgic_v3_probe before returning the
>>> error code from the call to kvm_register_device_ops to the caller
>>> of the function vgic_v3_probe.
>>>
>>> Signed-off-by: Nicholas Krause <xerofoify@xxxxxxxxx>
>>> ---
>>> virt/kvm/arm/vgic-v3.c | 10 +++++++---
>>> 1 file changed, 7 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/virt/kvm/arm/vgic-v3.c b/virt/kvm/arm/vgic-v3.c
>>> index dff0602..5102aa2 100644
>>> --- a/virt/kvm/arm/vgic-v3.c
>>> +++ b/virt/kvm/arm/vgic-v3.c
>>> @@ -264,12 +264,16 @@ int vgic_v3_probe(struct device_node *vgic_node,
>>> } else {
>>> vgic->vcpu_base = vcpu_res.start;
>>> vgic->can_emulate_gicv2 = true;
>>> - 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);
>>> + if (ret)
>>> + goto out;
>>> }
>>> if (vgic->vcpu_base == 0)
>>> kvm_info("disabling GICv2 emulation\n");
>>> - 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);
>>> + if (ret)
>>> + goto out;
>>>
>>> vgic->vctrl_base = NULL;
>>> vgic->type = VGIC_V3;
>>>
>>
>> This really should never happen. Perhaps kvm_register_device_ops should
>> instead return void, and WARN() when it currently returns an error.
>>
>> Paolo
>>
> Paolo,
> I would like to do what you want but after tracing the callers of this function I found
> this structure and wasn't sure if it can handle void function pointers.
> static const struct of_device_id vgic_ids[] = {
> { .compatible = "arm,cortex-a15-gic", .data = vgic_v2_probe, },
> { .compatible = "arm,cortex-a7-gic", .data = vgic_v2_probe, },
> { .compatible = "arm,gic-400", .data = vgic_v2_probe, },
> { .compatible = "arm,gic-v3", .data = vgic_v3_probe, },
> {},
> };
> If this structure of function pointers can handle function pointers with a return type of
> void I will be glad to do what you request otherwise this would require a major rewrite
> of kvm arm subsystem for a very simple bug fix.
Just like Paolo said, the error you report should never happen, and
would be caught by a WARN_ON() the first time anyone boots the kernel.
Also, failing to register the device ops results in not being able to
instantiate a VGIC. No harm done. I really don't understand why you want
to rewrite the probe functions.
There is plenty of things that could use a major rewrite in KVM/ARM, but
this is just not one of them.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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