Re: [PATCH] virt: kvm: arm: vgic: Process the failure case when kvm_register_device_ops() fails

From: Chen Gang
Date: Fri Nov 14 2014 - 09:05:34 EST


On 11/13/2014 11:30 PM, Marc Zyngier wrote:
> On 13/11/14 15:04, Chen Gang wrote:
>> When kvm_register_device_ops() fails, also need call free_percpu_irq()
>> just like others have down within kvm_vgic_hyp_init().
>>
>> Signed-off-by: Chen Gang <gang.chen.5i5j@xxxxxxxxx>
>> ---
>> virt/kvm/arm/vgic.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
>> index 3aaca49..b799f17 100644
>> --- a/virt/kvm/arm/vgic.c
>> +++ b/virt/kvm/arm/vgic.c
>> @@ -2470,8 +2470,14 @@ int kvm_vgic_hyp_init(void)
>>
>> on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
>>
>> - return 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) {
>> + kvm_err("Cannot register device ops\n");
>> + goto out_free_irq;
>> + }
>> +
>> + return 0;
>>
>> out_free_irq:
>> free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
>>
>
> Awesome. You're now freeing a per-cpu interrupt after just after having
> enabled it on all CPUs. What could possibly go wrong?
>

OK, thanks. What you said sound reasonable to me. Need call on_each_cpu
for disable_percpu_irq(). Also need call __unregister_cpu_notifier(),
and need a new function vgic_arch_unsetup() for arm64.

I shall send patch v2 for it.

Thanks.
--
Chen Gang

Open share and attitude like air water and life which God blessed
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