[PATCH v2] Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq

[PATCH v2] Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq

[Stefano Stabellini]

Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq

Use the new hypercall PHYSDEVOP_get_free_pirq to ask Xen to allocate a
pirq. Remove the unsupported PHYSDEVOP_get_nr_pirqs hypercall to get the
amount of pirq available.

Changes since v1:

- if PHYSDEVOP_get_free_pirq is not implemented, start pirq allocation
from 0 instead of 16. The pirq number 16 is not actually meaningful for
Xen.

- Remove nr_pirqs, it is not needed anymore. Add a comment to specify
that we don't actually know the upper limit of the pirq number range.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 2811bb9..072af50 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -105,7 +105,6 @@ struct irq_info
 
 static struct irq_info *irq_info;
 static int *pirq_to_irq;
-static int nr_pirqs;
 
 static int *evtchn_to_irq;
 struct cpu_evtchn_s {
@@ -385,12 +384,17 @@ static int get_nr_hw_irqs(void)
 	return ret;
 }
 
-/* callers of this function should make sure that PHYSDEVOP_get_nr_pirqs
- * succeeded otherwise nr_pirqs won't hold the right value */
-static int find_unbound_pirq(void)
+static int find_unbound_pirq(int type)
 {
-	int i;
-	for (i = nr_pirqs-1; i >= 0; i--) {
+	int rc, i;
+	struct physdev_get_free_pirq op_get_free_pirq;
+	op_get_free_pirq.type = type;
+
+	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
+	if (!rc)
+		return op_get_free_pirq.pirq;
+
+	for (i = 0; i <= nr_irqs-1; i++) {
 		if (pirq_to_irq[i] < 0)
 			return i;
 	}
@@ -611,9 +615,9 @@ int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
 
 	spin_lock(&irq_mapping_update_lock);
 
-	if ((pirq > nr_pirqs) || (gsi > nr_irqs)) {
+	if ((pirq > nr_irqs) || (gsi > nr_irqs)) {
 		printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n",
-			pirq > nr_pirqs ? "nr_pirqs" :"",
+			pirq > nr_irqs ? "nr_pirqs" :"",
 			gsi > nr_irqs ? "nr_irqs" : "");
 		goto out;
 	}
@@ -672,7 +676,7 @@ void xen_allocate_pirq_msi(char *name, int *irq, int *pirq)
 	if (*irq == -1)
 		goto out;
 
-	*pirq = find_unbound_pirq();
+	*pirq = find_unbound_pirq(MAP_PIRQ_TYPE_MSI);
 	if (*pirq == -1)
 		goto out;
 
@@ -1506,26 +1510,17 @@ void xen_callback_vector(void) {}
 
 void __init xen_init_IRQ(void)
 {
-	int i, rc;
-	struct physdev_nr_pirqs op_nr_pirqs;
+	int i;
 
 	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
 				    GFP_KERNEL);
 	irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
 
-	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
-	if (rc < 0) {
-		nr_pirqs = nr_irqs;
-		if (rc != -ENOSYS)
-			printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned rc=%d\n", rc);
-	} else {
-		if (xen_pv_domain() && !xen_initial_domain())
-			nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs);
-		else
-			nr_pirqs = op_nr_pirqs.nr_pirqs;
-	}
-	pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL);
-	for (i = 0; i < nr_pirqs; i++)
+	/* We are using nr_irqs as the maximum number of pirq available but
+	 * that number is actually chosen by Xen and we don't know exactly
+	 * what it is. Be careful choosing high pirq numbers. */
+	pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
+	for (i = 0; i < nr_irqs; i++)
 		pirq_to_irq[i] = -1;
 
 	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 2b2c66c..534cac8 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -188,6 +188,16 @@ struct physdev_nr_pirqs {
     uint32_t nr_pirqs;
 };
 
+/* type is MAP_PIRQ_TYPE_GSI or MAP_PIRQ_TYPE_MSI
+ * the hypercall returns a free pirq */
+#define PHYSDEVOP_get_free_pirq    23
+struct physdev_get_free_pirq {
+    /* IN */ 
+    int type;
+    /* OUT */
+    uint32_t pirq;
+};
+
 /*
  * Notify that some PIRQ-bound event channels have been unmasked.
  * ** This command is obsolete since interface version 0x00030202 and is **

Re: [Xen-devel] [PATCH v2] Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq

[Jeremy Fitzhardinge]

On 11/24/2010 11:22 AM, Stefano Stabellini wrote:
> Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq
>
> Use the new hypercall PHYSDEVOP_get_free_pirq to ask Xen to allocate a
> pirq. Remove the unsupported PHYSDEVOP_get_nr_pirqs hypercall to get the
> amount of pirq available.
>
> Changes since v1:
>
> - if PHYSDEVOP_get_free_pirq is not implemented, start pirq allocation
> from 0 instead of 16. The pirq number 16 is not actually meaningful for
> Xen.
>
> - Remove nr_pirqs, it is not needed anymore. Add a comment to specify
> that we don't actually know the upper limit of the pirq number range.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>
>
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index 2811bb9..072af50 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -105,7 +105,6 @@ struct irq_info
>  
>  static struct irq_info *irq_info;
>  static int *pirq_to_irq;
> -static int nr_pirqs;
>  
>  static int *evtchn_to_irq;
>  struct cpu_evtchn_s {
> @@ -385,12 +384,17 @@ static int get_nr_hw_irqs(void)
>  	return ret;
>  }
>  
> -/* callers of this function should make sure that PHYSDEVOP_get_nr_pirqs
> - * succeeded otherwise nr_pirqs won't hold the right value */
> -static int find_unbound_pirq(void)
> +static int find_unbound_pirq(int type)
>  {
> -	int i;
> -	for (i = nr_pirqs-1; i >= 0; i--) {
> +	int rc, i;
> +	struct physdev_get_free_pirq op_get_free_pirq;
> +	op_get_free_pirq.type = type;
> +
> +	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
> +	if (!rc)
> +		return op_get_free_pirq.pirq;
> +
> +	for (i = 0; i <= nr_irqs-1; i++) {

That seems needlessly complex.  What's wrong with "i < nr_irqs"?  Are
you trying to express something specific with this?
>  		if (pirq_to_irq[i] < 0)
>  			return i;
>  	}
> @@ -611,9 +615,9 @@ int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
>  
>  	spin_lock(&irq_mapping_update_lock);
>  
> -	if ((pirq > nr_pirqs) || (gsi > nr_irqs)) {
> +	if ((pirq > nr_irqs) || (gsi > nr_irqs)) {
>  		printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n",
> -			pirq > nr_pirqs ? "nr_pirqs" :"",
> +			pirq > nr_irqs ? "nr_pirqs" :"",
>  			gsi > nr_irqs ? "nr_irqs" : "");
>  		goto out;
>  	}
> @@ -672,7 +676,7 @@ void xen_allocate_pirq_msi(char *name, int *irq, int *pirq)
>  	if (*irq == -1)
>  		goto out;
>  
> -	*pirq = find_unbound_pirq();
> +	*pirq = find_unbound_pirq(MAP_PIRQ_TYPE_MSI);
>  	if (*pirq == -1)
>  		goto out;
>  
> @@ -1506,26 +1510,17 @@ void xen_callback_vector(void) {}
>  
>  void __init xen_init_IRQ(void)
>  {
> -	int i, rc;
> -	struct physdev_nr_pirqs op_nr_pirqs;
> +	int i;
>  
>  	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
>  				    GFP_KERNEL);
>  	irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
>  
> -	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
> -	if (rc < 0) {
> -		nr_pirqs = nr_irqs;
> -		if (rc != -ENOSYS)
> -			printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned rc=%d\n", rc);
> -	} else {
> -		if (xen_pv_domain() && !xen_initial_domain())
> -			nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs);
> -		else
> -			nr_pirqs = op_nr_pirqs.nr_pirqs;
> -	}
> -	pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL);
> -	for (i = 0; i < nr_pirqs; i++)
> +	/* We are using nr_irqs as the maximum number of pirq available but
> +	 * that number is actually chosen by Xen and we don't know exactly
> +	 * what it is. Be careful choosing high pirq numbers. */
> +	pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
> +	for (i = 0; i < nr_irqs; i++)
>  		pirq_to_irq[i] = -1;
>  
>  	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index 2b2c66c..534cac8 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -188,6 +188,16 @@ struct physdev_nr_pirqs {
>      uint32_t nr_pirqs;
>  };
>  
> +/* type is MAP_PIRQ_TYPE_GSI or MAP_PIRQ_TYPE_MSI
> + * the hypercall returns a free pirq */
> +#define PHYSDEVOP_get_free_pirq    23
> +struct physdev_get_free_pirq {

I guess it doesn't really matter, and it's probably a bit late, but this
seems like an odd name.  Normally I'd think of this as an allocation, so
something like PHYSDEVOP_alloc_pirq.

    J

Re: [Xen-devel] [PATCH v2] Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq

[Stefano Stabellini]

On Wed, 24 Nov 2010, Jeremy Fitzhardinge wrote:
> On 11/24/2010 11:22 AM, Stefano Stabellini wrote:
> > Use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq
> >
> > Use the new hypercall PHYSDEVOP_get_free_pirq to ask Xen to allocate a
> > pirq. Remove the unsupported PHYSDEVOP_get_nr_pirqs hypercall to get the
> > amount of pirq available.
> >
> > Changes since v1:
> >
> > - if PHYSDEVOP_get_free_pirq is not implemented, start pirq allocation
> > from 0 instead of 16. The pirq number 16 is not actually meaningful for
> > Xen.
> >
> > - Remove nr_pirqs, it is not needed anymore. Add a comment to specify
> > that we don't actually know the upper limit of the pirq number range.
> >
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> >
> >
> > diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> > index 2811bb9..072af50 100644
> > --- a/drivers/xen/events.c
> > +++ b/drivers/xen/events.c
> > @@ -105,7 +105,6 @@ struct irq_info
> >  
> >  static struct irq_info *irq_info;
> >  static int *pirq_to_irq;
> > -static int nr_pirqs;
> >  
> >  static int *evtchn_to_irq;
> >  struct cpu_evtchn_s {
> > @@ -385,12 +384,17 @@ static int get_nr_hw_irqs(void)
> >  	return ret;
> >  }
> >  
> > -/* callers of this function should make sure that PHYSDEVOP_get_nr_pirqs
> > - * succeeded otherwise nr_pirqs won't hold the right value */
> > -static int find_unbound_pirq(void)
> > +static int find_unbound_pirq(int type)
> >  {
> > -	int i;
> > -	for (i = nr_pirqs-1; i >= 0; i--) {
> > +	int rc, i;
> > +	struct physdev_get_free_pirq op_get_free_pirq;
> > +	op_get_free_pirq.type = type;
> > +
> > +	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
> > +	if (!rc)
> > +		return op_get_free_pirq.pirq;
> > +
> > +	for (i = 0; i <= nr_irqs-1; i++) {
> 
> That seems needlessly complex.  What's wrong with "i < nr_irqs"?  Are
> you trying to express something specific with this?

Yeah, good point.


> >  		if (pirq_to_irq[i] < 0)
> >  			return i;
> >  	}
> > @@ -611,9 +615,9 @@ int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
> >  
> >  	spin_lock(&irq_mapping_update_lock);
> >  
> > -	if ((pirq > nr_pirqs) || (gsi > nr_irqs)) {
> > +	if ((pirq > nr_irqs) || (gsi > nr_irqs)) {
> >  		printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n",
> > -			pirq > nr_pirqs ? "nr_pirqs" :"",
> > +			pirq > nr_irqs ? "nr_pirqs" :"",
> >  			gsi > nr_irqs ? "nr_irqs" : "");
> >  		goto out;
> >  	}
> > @@ -672,7 +676,7 @@ void xen_allocate_pirq_msi(char *name, int *irq, int *pirq)
> >  	if (*irq == -1)
> >  		goto out;
> >  
> > -	*pirq = find_unbound_pirq();
> > +	*pirq = find_unbound_pirq(MAP_PIRQ_TYPE_MSI);
> >  	if (*pirq == -1)
> >  		goto out;
> >  
> > @@ -1506,26 +1510,17 @@ void xen_callback_vector(void) {}
> >  
> >  void __init xen_init_IRQ(void)
> >  {
> > -	int i, rc;
> > -	struct physdev_nr_pirqs op_nr_pirqs;
> > +	int i;
> >  
> >  	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
> >  				    GFP_KERNEL);
> >  	irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
> >  
> > -	rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
> > -	if (rc < 0) {
> > -		nr_pirqs = nr_irqs;
> > -		if (rc != -ENOSYS)
> > -			printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned rc=%d\n", rc);
> > -	} else {
> > -		if (xen_pv_domain() && !xen_initial_domain())
> > -			nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs);
> > -		else
> > -			nr_pirqs = op_nr_pirqs.nr_pirqs;
> > -	}
> > -	pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL);
> > -	for (i = 0; i < nr_pirqs; i++)
> > +	/* We are using nr_irqs as the maximum number of pirq available but
> > +	 * that number is actually chosen by Xen and we don't know exactly
> > +	 * what it is. Be careful choosing high pirq numbers. */
> > +	pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
> > +	for (i = 0; i < nr_irqs; i++)
> >  		pirq_to_irq[i] = -1;
> >  
> >  	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
> > diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> > index 2b2c66c..534cac8 100644
> > --- a/include/xen/interface/physdev.h
> > +++ b/include/xen/interface/physdev.h
> > @@ -188,6 +188,16 @@ struct physdev_nr_pirqs {
> >      uint32_t nr_pirqs;
> >  };
> >  
> > +/* type is MAP_PIRQ_TYPE_GSI or MAP_PIRQ_TYPE_MSI
> > + * the hypercall returns a free pirq */
> > +#define PHYSDEVOP_get_free_pirq    23
> > +struct physdev_get_free_pirq {
> 
> I guess it doesn't really matter, and it's probably a bit late, but this
> seems like an odd name.  Normally I'd think of this as an allocation, so
> something like PHYSDEVOP_alloc_pirq.
 
Unfortunately it is too late for that, unless we want to name this
hypercall differently between Xen and Linux and I don't think it is
a good idea.