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KVM: Split up MSI-X assigned device IRQ handler

PATCH Applied Jan Kiszka 3 participants 5 messages Sep 12, 2011 – Sep 14, 2011 KVM

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Jan Kiszka

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#0 lore raw

PATCH 1/1 KVM: Split up MSI-X assigned device IRQ handler

The threaded IRQ handler for MSI-X has almost nothing in common with the INTx/MSI handler. Move its code into a dedicated handler.

Signed-off-by Jan Kiszka <[email protected]>
---
 virt/kvm/assigned-dev.c |   32 +++++++++++++++++++-------------
 1 files changed, 19 insertions(+), 13 deletions(-)
virt/kvm/assigned-dev.c +19 -13
index 84ead54..7debe8c 100644
@@ -58,8 +58,6 @@ static int find_index_from_host_irq(struct kvm_assigned_dev_kernel
 static irqreturn_t kvm_assigned_dev_thread(int irq, void *dev_id)
 {
 	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
-	u32 vector;
-	int index;
 
 	if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_INTX) {
 		spin_lock(&assigned_dev->intx_lock);

@@ -68,20 +66,28 @@ static irqreturn_t kvm_assigned_dev_thread(int irq, void *dev_id)
 		spin_unlock(&assigned_dev->intx_lock);
 	}
 
-	if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) {
-		index = find_index_from_host_irq(assigned_dev, irq);
-		if (index >= 0) {
-			vector = assigned_dev->
-					guest_msix_entries[index].vector;
-			kvm_set_irq(assigned_dev->kvm,
-				    assigned_dev->irq_source_id, vector, 1);
-		}
-	} else
+	kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
+		    assigned_dev->guest_irq, 1);
+
+	return IRQ_HANDLED;
+}
+
+#ifdef __KVM_HAVE_MSIX
+static irqreturn_t kvm_assigned_dev_thread_msix(int irq, void *dev_id)
+{
+	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
+	int index = find_index_from_host_irq(assigned_dev, irq);
+	u32 vector;
+
+	if (index >= 0) {
+		vector = assigned_dev->guest_msix_entries[index].vector;
 		kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
-			    assigned_dev->guest_irq, 1);
+			    vector, 1);
+	}
 
 	return IRQ_HANDLED;
 }
+#endif
 
 /* Ack the irq line for an assigned device */
 static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)

@@ -279,7 +285,7 @@ static int assigned_device_enable_host_msix(struct kvm *kvm,
 
 	for (i = 0; i < dev->entries_nr; i++) {
 		r = request_threaded_irq(dev->host_msix_entries[i].vector,
-					 NULL, kvm_assigned_dev_thread,
+					 NULL, kvm_assigned_dev_thread_msix,
 					 0, dev->irq_name, dev);
 		if (r)
 			goto err;
Signature · 1 line
1.7.3.4
#1 lore raw
Quoted 5 lines

From: Jan Kiszka
Sent: Tuesday, September 13, 2011 12:58 AM

The threaded IRQ handler for MSI-X has almost nothing in common with the INTx/MSI handler. Move its code into a dedicated handler.

if it's desired to further go down this cleanup path, there's also no need to register ack notifier for MSI-X type device since all the logic there is simply a nop:

static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)

{
        struct kvm_assigned_dev_kernel *dev;

        if (kian->gsi == -1)
                return;

        dev = container_of(kian, struct kvm_assigned_dev_kernel,
                           ack_notifier);

        kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);

        /* The guest irq may be shared so this ack may be
         * from another device.
         */
        spin_lock(&dev->intx_lock);
        if (dev->host_irq_disabled) {
                enable_irq(dev->host_irq);
                dev->host_irq_disabled = false;
        }
        spin_unlock(&dev->intx_lock);
}

Thanks
Kevin

Quoted 76 lines
Signed-off-by Jan Kiszka <[email protected]>
---
 virt/kvm/assigned-dev.c |   32 +++++++++++++++++++-------------
 1 files changed, 19 insertions(+), 13 deletions(-)
virt/kvm/assigned-dev.c +0 -0
index 84ead54..7debe8c 100644
@@ -58,8 +58,6 @@ static int find_index_from_host_irq(struct

kvm_assigned_dev_kernel
static irqreturn_t kvm_assigned_dev_thread(int irq, void *dev_id) {

virt/kvm/assigned-dev.c +18 -12
 	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
-	u32 vector;
-	int index;
 
 	if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_INTX) {
 		spin_lock(&assigned_dev->intx_lock);

@@ -68,20 +66,28 @@ static irqreturn_t kvm_assigned_dev_thread(int irq,
 void *dev_id)
 		spin_unlock(&assigned_dev->intx_lock);
 	}
 
-	if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) {
-		index = find_index_from_host_irq(assigned_dev, irq);
-		if (index >= 0) {
-			vector = assigned_dev->
-					guest_msix_entries[index].vector;
-			kvm_set_irq(assigned_dev->kvm,
-				    assigned_dev->irq_source_id, vector, 1);
-		}
-	} else
+	kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
+		    assigned_dev->guest_irq, 1);
+
+	return IRQ_HANDLED;
+}
+
+#ifdef __KVM_HAVE_MSIX
+static irqreturn_t kvm_assigned_dev_thread_msix(int irq, void *dev_id)
+{
+	struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
+	int index = find_index_from_host_irq(assigned_dev, irq);
+	u32 vector;
+
+	if (index >= 0) {
+		vector = assigned_dev->guest_msix_entries[index].vector;
 		kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
-			    assigned_dev->guest_irq, 1);
+			    vector, 1);
+	}
 
 	return IRQ_HANDLED;
 }
+#endif
 
 /* Ack the irq line for an assigned device */

static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)

virt/kvm/assigned-dev.c +1 -1
@@ -279,7 +285,7 @@ static int assigned_device_enable_host_msix(struct
 kvm *kvm,
 
 	for (i = 0; i < dev->entries_nr; i++) {
 		r = request_threaded_irq(dev->host_msix_entries[i].vector,
-					 NULL, kvm_assigned_dev_thread,
+					 NULL, kvm_assigned_dev_thread_msix,
 					 0, dev->irq_name, dev);
 		if (r)

goto err;
--
1.7.3.4
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author
#2 lore raw
Quoted 9 lines · Kevin
Quoted 5 lines

From: Jan Kiszka
Sent: Tuesday, September 13, 2011 12:58 AM

The threaded IRQ handler for MSI-X has almost nothing in common with the INTx/MSI handler. Move its code into a dedicated handler.

if it's desired to further go down this cleanup path, there's also no need to register ack notifier for MSI-X type device since all the logic there is simply a nop:

You mean http://thread.gmane.org/gmane.comp.emulators.kvm.devel/79075? :)

Jan

Signature · 2 lines
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
#3 lore raw
Quoted 10 lines

From: Jan Kiszka [mailto:[email protected]]
Sent: Tuesday, September 13, 2011 3:30 PM

Quoted 6 lines · Kevin
Quoted 5 lines

From: Jan Kiszka
Sent: Tuesday, September 13, 2011 12:58 AM

The threaded IRQ handler for MSI-X has almost nothing in common with the INTx/MSI handler. Move its code into a dedicated handler.

Quoted 7 lines
Quoted 3 lines

if it's desired to further go down this cleanup path, there's also no need to register ack notifier for MSI-X type device since all the logic there is simply a nop:

You mean
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/79075? :)

yes, and sorry that I didn't catch that thread. :-)

Thanks
Kevin

Applied
#4 lore raw
In reply to Jan Kiszka
Quoted 7 lines · Jan Kiszka

The threaded IRQ handler for MSI-X has almost nothing in common with the INTx/MSI handler. Move its code into a dedicated handler.

Signed-off-by Jan Kiszka <[email protected]>
---
 virt/kvm/assigned-dev.c |   32 +++++++++++++++++++-------------
 1 files changed, 19 insertions(+), 13 deletions(-)

Applied, thanks.