diff mbox

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

Message ID 1435843047-6327-17-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Auger Eric July 2, 2015, 1:17 p.m. UTC
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(-)

Comments

Auger Eric July 2, 2015, 1:53 p.m. UTC | #1
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);
>>  		}
>>  	}
>>  
>>
Auger Eric July 6, 2015, 11:19 a.m. UTC | #2
Hi Feng,
On 07/06/2015 09:55 AM, Wu, Feng wrote:
> 
> 
>> -----Original Message-----
>> From: Eric Auger [mailto:eric.auger@linaro.org]
>> Sent: Thursday, July 02, 2015 9:17 PM
>> To: eric.auger@st.com; eric.auger@linaro.org;
>> linux-arm-kernel@lists.infradead.org; kvmarm@lists.cs.columbia.edu;
>> kvm@vger.kernel.org; christoffer.dall@linaro.org; marc.zyngier@arm.com;
>> alex.williamson@redhat.com; pbonzini@redhat.com; avi.kivity@gmail.com;
>> mtosatti@redhat.com; Wu, Feng; joro@8bytes.org;
>> b.reynal@virtualopensystems.com
>> Cc: linux-kernel@vger.kernel.org; patches@linaro.org
>> Subject: [RFC 16/17] KVM: eventfd: add irq bypass consumer management
>>
>> 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);
>> +	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);
> 
> There may be an issue here. 'irqfd' is freed in irqfd_deactivate() --> ... --.>irqfd_shutdown(),
> and irqfd_deactivate() can be called in the other two places below:
> 	- irqfd_wakeup()
> 	- kvm_irqfd_release()
> I think we also need to call irq_bypass_unregister_consumer() there, right?
yes you're right. what about doing the unregistration in irqfd_shutdown
then?

Thanks for spotting this.

Eric

> 
> Thanks,
> Feng
> 
> 
>>  		}
>>  	}
>>
>> --
>> 1.9.1
>
diff mbox

Patch

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);
+	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);
 		}
 	}