Subject: [PATCH v5 5/5] KVM: eventfd: add irq bypass consumer management

From: [email-masked] (Eric Auger)
Date: Thu, 13 Aug 2015 11:19:21 +0200

Hi Alex,
On 08/12/2015 09:05 PM, Alex Williamson wrote:
> On Mon, 2015-08-10 at 15:31 +0200, Eric Auger wrote:
>> This patch adds the registration/unregistration of an
>> irq_bypass_consumer on irqfd assignment/deassignment.
>>
>> Signed-off-by: Eric Auger <[email-masked]>
>> Signed-off-by: Feng Wu <[email-masked]>
>>
>> ---
>>
>> v4 -> v5:
>> - due to removal of static inline stubs, add
>>   #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>>   around consumer registration/unregistration
>> - add pr_info when registration fails
>>
>> 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        | 15 +++++++++++++++
>>  2 files changed, 17 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..d7a230f 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 +141,9 @@ irqfd_shutdown(struct work_struct *work)
>>  	/*
>>  	 * It is now safe to release the object's resources
>>  	 */
>> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>> +	irq_bypass_unregister_consumer(&irqfd->consumer);
>> +#endif
>>  	eventfd_ctx_put(irqfd->eventfd);
>>  	kfree(irqfd);
>>  }
>> @@ -379,6 +383,17 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>>  	 * we might race against the POLLHUP
>>  	 */
>>  	fdput(f);
>> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>> +	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);
>> +	if (ret)
>> +		pr_info("irq bypass consumer (token %p) registration fails: %d\n",
>> +				irqfd->consumer.token, ret);
>> +#endif
> 
> Does this series compile on its own?  Aren't all these arch function
> unresolved?
yes it does since by default CONFIG_HAVE_KVM_IRQ_BYPASS is not defined

Best Regards

Eric
>>  	return 0;