Hi Alex,
On 08/07/2015 10:09 PM, Alex Williamson wrote:
> On Mon, 2015-08-03 at 19:20 +0200, Eric Auger wrote:
>> This patch adds the registration/unregistration of an
>> irq_bypass_consumer on irqfd assignment/deassignment.
>>
>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>> Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
>>
>> ---
>>
>> v2 -> v3 (Feng Wu):
>> - Use kvm_arch_irq_bypass_start
>> - Remove kvm_arch_irq_bypass_update
>> - Add member 'struct irq_bypass_producer *producer' in
>> 'struct kvm_kernel_irqfd', it is needed by posted interrupt.
>> - Remove 'irq_bypass_unregister_consumer' in kvm_irqfd_deassign()
>>
>> v1 -> v2:
>> - populate of kvm and gsi removed
>> - unregister the consumer on irqfd_shutdown
>> ---
>> include/linux/kvm_irqfd.h | 2 ++
>> virt/kvm/eventfd.c | 10 ++++++++++
>> 2 files changed, 12 insertions(+)
>>
>> diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
>> index f926b39..0c1de05 100644
>> --- a/include/linux/kvm_irqfd.h
>> +++ b/include/linux/kvm_irqfd.h
>> @@ -64,6 +64,8 @@ struct kvm_kernel_irqfd {
>> struct list_head list;
>> poll_table pt;
>> struct work_struct shutdown;
>> + struct irq_bypass_consumer consumer;
>> + struct irq_bypass_producer *producer;
>> };
>>
>> #endif /* __LINUX_KVM_IRQFD_H */
>> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
>> index 647ffb8..08855de 100644
>> --- a/virt/kvm/eventfd.c
>> +++ b/virt/kvm/eventfd.c
>> @@ -35,6 +35,7 @@
>> #include <linux/srcu.h>
>> #include <linux/slab.h>
>> #include <linux/seqlock.h>
>> +#include <linux/irqbypass.h>
>> #include <trace/events/kvm.h>
>>
>> #include <kvm/iodev.h>
>> @@ -140,6 +141,7 @@ irqfd_shutdown(struct work_struct *work)
>> /*
>> * It is now safe to release the object's resources
>> */
>> + irq_bypass_unregister_consumer(&irqfd->consumer);
>> eventfd_ctx_put(irqfd->eventfd);
>> kfree(irqfd);
>> }
>> @@ -380,6 +382,14 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>> */
>> fdput(f);
>>
>> + irqfd->consumer.token = (void *)irqfd->eventfd;
>> + irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
>> + irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
>> + irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
>> + irqfd->consumer.start = kvm_arch_irq_bypass_start;
>> + ret = irq_bypass_register_consumer(&irqfd->consumer);
>> + WARN_ON(ret);
>
> This seems like a lazy way to handle this error. What is the stack
> trace from this WARN_ON going to tell us that we didn't already know?
> If we get the WARN_ON, it's probably means that an incompatible producer
> registered the token first. It means we can't do bypass, but it doesn't
> tell us anything about whether bypass is or is not enabled. Wouldn't a
> pr_info/debug() suffice for that? Thanks,
Sure I will output some more relevant traces.
Thanks
Eric
>
> Alex
>
>> +
>> return 0;
>>
>> fail:
>
>
>
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