Re: [RFC 16/17] KVM: eventfd: add irq bypass consumer management

Eric Auger
2015-07-02T13:53:56Z

On 07/02/2015 03:42 PM, Paolo Bonzini wrote:
>
>
> On 02/07/2015 15:17, 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@linaro.org>
>> ---
>> virt/kvm/eventfd.c | 22 +++++++++++++++++++---
>> 1 file changed, 19 insertions(+), 3 deletions(-)
>>
>> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
>> index f3da161..425a47b 100644
>> --- a/virt/kvm/eventfd.c
>> +++ b/virt/kvm/eventfd.c
>> @@ -34,6 +34,7 @@
>> #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>
>> @@ -93,6 +94,7 @@ struct _irqfd {
>> struct list_head list;
>> poll_table pt;
>> struct work_struct shutdown;
>> + struct irq_bypass_consumer *cons;
>> };
>>
>> static struct workqueue_struct *irqfd_cleanup_wq;
>> @@ -429,7 +431,21 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>> */
>> fdput(f);
>>
>> - /* irq_bypass_register_consumer(); */
>> + irqfd->cons = kzalloc(sizeof(struct irq_bypass_consumer),
>> + GFP_KERNEL);
>
> Apart from the struct embedding technique I suggested in patch 12, this
> looks very reasonable. Thanks!

Hi Paolo,

thanks for the swift feedback. I will respin shortly with the advised
embedding technique.

Best Regards

Eric
>
> Paolo
>
>> + if (!irqfd->cons) {
>> + ret = -ENOMEM;
>> + goto fail;
>> + }
>> + irqfd->cons->token = (void *)irqfd->eventfd;
>> + irqfd->cons->gsi = irqfd->gsi;
>> + irqfd->cons->kvm = kvm;
>> + irqfd->cons->add_producer = kvm_arch_add_producer;
>> + irqfd->cons->del_producer = kvm_arch_del_producer;
>> + irqfd->cons->stop_consumer = kvm_arch_stop_consumer;
>> + irqfd->cons->resume_consumer = kvm_arch_resume_consumer;
>> + ret = irq_bypass_register_consumer(irqfd->cons);
>> + WARN_ON(ret);
>>
>> return 0;
>>
>> @@ -530,8 +546,6 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
>> struct _irqfd *irqfd, *tmp;
>> struct eventfd_ctx *eventfd;
>>
>> - /* irq_bypass_unregister_consumer() */
>> -
>> eventfd = eventfd_ctx_fdget(args->fd);
>> if (IS_ERR(eventfd))
>> return PTR_ERR(eventfd);
>> @@ -550,6 +564,8 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
>> irqfd->irq_entry.type = 0;
>> write_seqcount_end(&irqfd->irq_entry_sc);
>> irqfd_deactivate(irqfd);
>> + irq_bypass_unregister_consumer(irqfd->cons);
>> + kfree(irqfd->cons);
>> }
>> }
>>
>>