diff mbox

[1/8,v2] Change irq routing table to use gsi indexed array.

Message ID 1249993895-11119-2-git-send-email-gleb@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Gleb Natapov Aug. 11, 2009, 12:31 p.m. UTC
Use gsi indexed array instead of scanning all entries on each interrupt
injection.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 include/linux/kvm_host.h |   16 ++++++++--
 virt/kvm/irq_comm.c      |   77 +++++++++++++++++++++++++---------------------
 virt/kvm/kvm_main.c      |    1 -
 3 files changed, 55 insertions(+), 39 deletions(-)

Comments

Avi Kivity Aug. 12, 2009, 8:05 a.m. UTC | #1
On 08/11/2009 03:31 PM, Gleb Natapov wrote:
> Use gsi indexed array instead of scanning all entries on each interrupt
> injection.
>
>
> @@ -163,20 +166,23 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
>
>   void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
>   {
> -	struct kvm_kernel_irq_routing_entry *e;
>   	struct kvm_irq_ack_notifier *kian;
>   	struct hlist_node *n;
>   	unsigned gsi = pin;
> +	int i;
>
>   	trace_kvm_ack_irq(irqchip, pin);
>
> -	list_for_each_entry(e,&kvm->irq_routing, link)
> +	for (i = 0; i<  kvm->irq_routing->nr_rt_entries; i++) {
> +		struct kvm_kernel_irq_routing_entry *e;
> +		e =&kvm->irq_routing->rt_entries[i];
>   		if (e->type == KVM_IRQ_ROUTING_IRQCHIP&&
>   		e->irqchip.irqchip == irqchip&&
>   		e->irqchip.pin == pin) {
>   			gsi = e->gsi;
>   			break;
>   		}
> +	}
>    

Don't you need to iterate over all the entries for a gsi?
Gleb Natapov Aug. 12, 2009, 8:41 a.m. UTC | #2
On Wed, Aug 12, 2009 at 11:05:06AM +0300, Avi Kivity wrote:
> On 08/11/2009 03:31 PM, Gleb Natapov wrote:
>> Use gsi indexed array instead of scanning all entries on each interrupt
>> injection.
>>
>>
>> @@ -163,20 +166,23 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
>>
>>   void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
>>   {
>> -	struct kvm_kernel_irq_routing_entry *e;
>>   	struct kvm_irq_ack_notifier *kian;
>>   	struct hlist_node *n;
>>   	unsigned gsi = pin;
>> +	int i;
>>
>>   	trace_kvm_ack_irq(irqchip, pin);
>>
>> -	list_for_each_entry(e,&kvm->irq_routing, link)
>> +	for (i = 0; i<  kvm->irq_routing->nr_rt_entries; i++) {
>> +		struct kvm_kernel_irq_routing_entry *e;
>> +		e =&kvm->irq_routing->rt_entries[i];
>>   		if (e->type == KVM_IRQ_ROUTING_IRQCHIP&&
>>   		e->irqchip.irqchip == irqchip&&
>>   		e->irqchip.pin == pin) {
>>   			gsi = e->gsi;
>>   			break;
>>   		}
>> +	}
>>    
>
> Don't you need to iterate over all the entries for a gsi?
>
One pin/irqchip cannot be mapped to more than one GSI. Besides
this is what the current code does.

--
			Gleb.
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Avi Kivity Aug. 12, 2009, 9:06 a.m. UTC | #3
On 08/12/2009 11:41 AM, Gleb Natapov wrote:
> On Wed, Aug 12, 2009 at 11:05:06AM +0300, Avi Kivity wrote:
>    
>> On 08/11/2009 03:31 PM, Gleb Natapov wrote:
>>      
>>> Use gsi indexed array instead of scanning all entries on each interrupt
>>> injection.
>>>
>>>
>>> @@ -163,20 +166,23 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
>>>
>>>    void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
>>>    {
>>> -	struct kvm_kernel_irq_routing_entry *e;
>>>    	struct kvm_irq_ack_notifier *kian;
>>>    	struct hlist_node *n;
>>>    	unsigned gsi = pin;
>>> +	int i;
>>>
>>>    	trace_kvm_ack_irq(irqchip, pin);
>>>
>>> -	list_for_each_entry(e,&kvm->irq_routing, link)
>>> +	for (i = 0; i<   kvm->irq_routing->nr_rt_entries; i++) {
>>> +		struct kvm_kernel_irq_routing_entry *e;
>>> +		e =&kvm->irq_routing->rt_entries[i];
>>>    		if (e->type == KVM_IRQ_ROUTING_IRQCHIP&&
>>>    		e->irqchip.irqchip == irqchip&&
>>>    		e->irqchip.pin == pin) {
>>>    			gsi = e->gsi;
>>>    			break;
>>>    		}
>>> +	}
>>>
>>>        
>> Don't you need to iterate over all the entries for a gsi?
>>
>>      
> One pin/irqchip cannot be mapped to more than one GSI.

But one gsi can be mapped to multiple irqchip/pin combinations.

> Besides
> this is what the current code does.
>    

The current code stops on first match; the new code doesn't consider 
some entries at all.
diff mbox

Patch

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f814512..09df31d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -129,7 +129,17 @@  struct kvm_kernel_irq_routing_entry {
 		} irqchip;
 		struct msi_msg msi;
 	};
-	struct list_head link;
+	struct hlist_node link;
+};
+
+struct kvm_irq_routing_table {
+	struct kvm_kernel_irq_routing_entry *rt_entries;
+	u32 nr_rt_entries;
+	/*
+	 * Array indexed by gsi. Each entry contains list of irq chips
+	 * the gsi is connected to.
+	 */
+	struct hlist_head map[0];
 };
 
 struct kvm {
@@ -167,7 +177,7 @@  struct kvm {
 
 	struct mutex irq_lock;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
-	struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */
+	struct kvm_irq_routing_table *irq_routing;
 	struct hlist_head mask_notifier_list;
 #endif
 
@@ -396,7 +406,7 @@  void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic,
 				   union kvm_ioapic_redirect_entry *entry,
 				   unsigned long *deliver_bitmask);
 #endif
-int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 001663f..a9d2262 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -122,11 +122,13 @@  static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
  *  = 0   Interrupt was coalesced (previous irq is still pending)
  *  > 0   Number of CPUs interrupt was delivered to
  */
-int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 {
 	struct kvm_kernel_irq_routing_entry *e;
 	unsigned long *irq_state, sig_level;
 	int ret = -1;
+	struct kvm_irq_routing_table *irq_rt;
+	struct hlist_node *n;
 
 	trace_kvm_set_irq(irq, level, irq_source_id);
 
@@ -150,8 +152,9 @@  int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
 	 * IOAPIC.  So set the bit in both. The guest will ignore
 	 * writes to the unused one.
 	 */
-	list_for_each_entry(e, &kvm->irq_routing, link)
-		if (e->gsi == irq) {
+	irq_rt = kvm->irq_routing;
+	if (irq < irq_rt->nr_rt_entries)
+		hlist_for_each_entry(e, n, &irq_rt->map[irq], link) {
 			int r = e->set(e, kvm, sig_level);
 			if (r < 0)
 				continue;
@@ -163,20 +166,23 @@  int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
 
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 {
-	struct kvm_kernel_irq_routing_entry *e;
 	struct kvm_irq_ack_notifier *kian;
 	struct hlist_node *n;
 	unsigned gsi = pin;
+	int i;
 
 	trace_kvm_ack_irq(irqchip, pin);
 
-	list_for_each_entry(e, &kvm->irq_routing, link)
+	for (i = 0; i < kvm->irq_routing->nr_rt_entries; i++) {
+		struct kvm_kernel_irq_routing_entry *e;
+		e = &kvm->irq_routing->rt_entries[i];
 		if (e->type == KVM_IRQ_ROUTING_IRQCHIP &&
 		    e->irqchip.irqchip == irqchip &&
 		    e->irqchip.pin == pin) {
 			gsi = e->gsi;
 			break;
 		}
+	}
 
 	hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list, link)
 		if (kian->gsi == gsi)
@@ -267,22 +273,15 @@  void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
 			kimn->func(kimn, mask);
 }
 
-static void __kvm_free_irq_routing(struct list_head *irq_routing)
-{
-	struct kvm_kernel_irq_routing_entry *e, *n;
-
-	list_for_each_entry_safe(e, n, irq_routing, link)
-		kfree(e);
-}
-
 void kvm_free_irq_routing(struct kvm *kvm)
 {
 	mutex_lock(&kvm->irq_lock);
-	__kvm_free_irq_routing(&kvm->irq_routing);
+	kfree(kvm->irq_routing);
 	mutex_unlock(&kvm->irq_lock);
 }
 
-static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+static int setup_routing_entry(struct kvm_irq_routing_table *rt,
+			       struct kvm_kernel_irq_routing_entry *e,
 			       const struct kvm_irq_routing_entry *ue)
 {
 	int r = -EINVAL;
@@ -319,6 +318,8 @@  static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
 	default:
 		goto out;
 	}
+
+	hlist_add_head(&e->link, &rt->map[e->gsi]);
 	r = 0;
 out:
 	return r;
@@ -330,43 +331,49 @@  int kvm_set_irq_routing(struct kvm *kvm,
 			unsigned nr,
 			unsigned flags)
 {
-	struct list_head irq_list = LIST_HEAD_INIT(irq_list);
-	struct list_head tmp = LIST_HEAD_INIT(tmp);
-	struct kvm_kernel_irq_routing_entry *e = NULL;
-	unsigned i;
+	struct kvm_irq_routing_table *new, *old;
+	u32 i, nr_rt_entries = 0;
 	int r;
 
 	for (i = 0; i < nr; ++i) {
+		if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
+			return -EINVAL;
+		nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
+	}
+
+	nr_rt_entries += 1;
+
+	new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
+		      + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
+		      GFP_KERNEL);
+
+	if (!new)
+		return -ENOMEM;
+
+	new->rt_entries = (void *)&new->map[nr_rt_entries];
+
+	new->nr_rt_entries = nr_rt_entries;
+
+	for (i = 0; i < nr; ++i) {
 		r = -EINVAL;
-		if (ue->gsi >= KVM_MAX_IRQ_ROUTES)
-			goto out;
 		if (ue->flags)
 			goto out;
-		r = -ENOMEM;
-		e = kzalloc(sizeof(*e), GFP_KERNEL);
-		if (!e)
-			goto out;
-		r = setup_routing_entry(e, ue);
+		r = setup_routing_entry(new, &new->rt_entries[i], ue);
 		if (r)
 			goto out;
 		++ue;
-		list_add(&e->link, &irq_list);
-		e = NULL;
 	}
 
 	mutex_lock(&kvm->irq_lock);
-	list_splice(&kvm->irq_routing, &tmp);
-	INIT_LIST_HEAD(&kvm->irq_routing);
-	list_splice(&irq_list, &kvm->irq_routing);
-	INIT_LIST_HEAD(&irq_list);
-	list_splice(&tmp, &irq_list);
+	old = kvm->irq_routing;
+	kvm->irq_routing = new;
 	mutex_unlock(&kvm->irq_lock);
 
+	new = old;
 	r = 0;
 
 out:
-	kfree(e);
-	__kvm_free_irq_routing(&irq_list);
+	kfree(new);
 	return r;
 }
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1df4c04..e8b03ee 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -944,7 +944,6 @@  static struct kvm *kvm_create_vm(void)
 	if (IS_ERR(kvm))
 		goto out;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
-	INIT_LIST_HEAD(&kvm->irq_routing);
 	INIT_HLIST_HEAD(&kvm->mask_notifier_list);
 #endif