[PATCH] xen: add support for MSI message groups

[PATCH] xen: add support for MSI message groups

[Roger Pau Monne]

Add support for MSI message groups for Xen Dom0 using the
MAP_PIRQ_TYPE_MULTI_MSI pirq map type.

In order to keep track of which pirq is the first one in the group all
pirqs in the MSI group except for the first one have the newly
introduced PIRQ_MSI_GROUP flag set. This prevents calling
PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
first pirq in the group.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Tested with an Intel ICH8 AHCI SATA controller.
---
 arch/x86/pci/xen.c                   |   29 ++++++++++++++------
 drivers/xen/events/events_base.c     |   47 +++++++++++++++++++++++-----------
 drivers/xen/events/events_internal.h |    1 +
 include/xen/events.h                 |    2 +-
 include/xen/interface/physdev.h      |    1 +
 5 files changed, 55 insertions(+), 25 deletions(-)

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702..905956f 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	i = 0;
 	list_for_each_entry(msidesc, &dev->msi_list, list) {
 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
 					       (type == PCI_CAP_ID_MSIX) ?
 					       "pcifront-msi-x" :
 					       "pcifront-msi",
@@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 				"xen: msi already bound to pirq=%d\n", pirq);
 		}
 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
 					       (type == PCI_CAP_ID_MSIX) ?
 					       "msi-x" : "msi",
 					       DOMID_SELF);
@@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	int ret = 0;
 	struct msi_desc *msidesc;
 
-	if (type == PCI_CAP_ID_MSI && nvec > 1)
-		return 1;
-
 	list_for_each_entry(msidesc, &dev->msi_list, list) {
 		struct physdev_map_pirq map_irq;
 		domid_t domid;
@@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 			      (pci_domain_nr(dev->bus) << 16);
 		map_irq.devfn = dev->devfn;
 
-		if (type == PCI_CAP_ID_MSIX) {
+		if (type == PCI_CAP_ID_MSI && nvec > 1) {
+			map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
+			map_irq.entry_nr = nvec;
+		} else if (type == PCI_CAP_ID_MSIX) {
 			int pos;
 			u32 table_offset, bir;
 
@@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 		if (pci_seg_supported)
 			ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
 						    &map_irq);
+		if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
+			/*
+			 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
+			 * there's nothing else we can do in this case.
+			 * Just set ret > 0 so driver can retry with
+			 * single MSI.
+			 */
+			ret = 1;
+			goto out;
+		}
 		if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
 			map_irq.type = MAP_PIRQ_TYPE_MSI;
 			map_irq.index = -1;
@@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 			goto out;
 		}
 
-		ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
-					       map_irq.pirq,
-					       (type == PCI_CAP_ID_MSIX) ?
-					       "msi-x" : "msi",
-						domid);
+		ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
+		                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
+		                               (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
+		                               domid);
 		if (ret < 0)
 			goto out;
 	}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index f4a9e33..ff20ae2 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
-static int __must_check xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irqs_dynamic(int nvec)
 {
 	int first = 0;
-	int irq;
+	int i, irq;
 
 #ifdef CONFIG_X86_IO_APIC
 	/*
@@ -408,14 +408,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
 		first = get_nr_irqs_gsi();
 #endif
 
-	irq = irq_alloc_desc_from(first, -1);
+	irq = irq_alloc_descs_from(first, nvec, -1);
 
-	if (irq >= 0)
-		xen_irq_init(irq);
+	if (irq >= 0) {
+		for (i = 0; i < nvec; i++)
+			xen_irq_init(irq + i);
+	}
 
 	return irq;
 }
 
+static inline int __must_check xen_allocate_irq_dynamic(void)
+{
+
+	return xen_allocate_irqs_dynamic(1);
+}
+
 static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 {
 	int irq;
@@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
 }
 
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid)
+			     int pirq, int nvec, const char *name, domid_t domid)
 {
-	int irq, ret;
+	int i, irq, ret;
 
 	mutex_lock(&irq_mapping_update_lock);
 
-	irq = xen_allocate_irq_dynamic();
+	irq = xen_allocate_irqs_dynamic(nvec);
 	if (irq < 0)
 		goto out;
 
-	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
-			name);
+	for (i = 0; i < nvec; i++) {
+		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+
+		ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
+					      i == 0 ? 0 : PIRQ_MSI_GROUP);
+		if (ret < 0)
+			goto error_irq;
+	}
 
-	ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
-	if (ret < 0)
-		goto error_irq;
 	ret = irq_set_msi_desc(irq, msidesc);
 	if (ret < 0)
 		goto error_irq;
@@ -764,7 +775,8 @@ out:
 	mutex_unlock(&irq_mapping_update_lock);
 	return irq;
 error_irq:
-	__unbind_from_irq(irq);
+	for (; i >= 0; i--)
+		__unbind_from_irq(irq + i);
 	mutex_unlock(&irq_mapping_update_lock);
 	return ret;
 }
@@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
 	if (!desc)
 		goto out;
 
-	if (xen_initial_domain()) {
+	/*
+	 * If trying to remove a vector in a MSI group different
+	 * than the first one skip the PIRQ unmap unless this vector
+	 * is the first one in the group.
+	 */
+	if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
 		unmap_irq.pirq = info->u.pirq.pirq;
 		unmap_irq.domid = info->u.pirq.domid;
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 677f41a..50c2050a 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -53,6 +53,7 @@ struct irq_info {
 
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
+#define PIRQ_MSI_GROUP	(1 << 2)
 
 struct evtchn_ops {
 	unsigned (*max_channels)(void);
diff --git a/include/xen/events.h b/include/xen/events.h
index c9c85cf..2ae7e03 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
 /* Bind an PSI pirq to an irq. */
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid);
+			     int pirq, int nvec, const char *name, domid_t domid);
 #endif
 
 /* De-allocates the above mentioned physical interrupt. */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 42721d1..eb13326d 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -131,6 +131,7 @@ struct physdev_irq {
 #define MAP_PIRQ_TYPE_GSI		0x1
 #define MAP_PIRQ_TYPE_UNKNOWN		0x2
 #define MAP_PIRQ_TYPE_MSI_SEG		0x3
+#define MAP_PIRQ_TYPE_MULTI_MSI		0x4
 
 #define PHYSDEVOP_map_pirq		13
 struct physdev_map_pirq {
-- 
1.7.7.5 (Apple Git-26)

Re: [Xen-devel] [PATCH] xen: add support for MSI message groups

[David Vrabel]

On 26/02/14 16:24, Roger Pau Monne wrote:
> Add support for MSI message groups for Xen Dom0 using the
> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
> 
> In order to keep track of which pirq is the first one in the group all
> pirqs in the MSI group except for the first one have the newly
> introduced PIRQ_MSI_GROUP flag set. This prevents calling
> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
> first pirq in the group.

Reviewed-by: David Vrabel <david.vrabel@citrix.com>

David

Re: [PATCH] xen: add support for MSI message groups

[David Vrabel]

On 26/02/14 16:24, Roger Pau Monne wrote:
> Add support for MSI message groups for Xen Dom0 using the
> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
> 
> In order to keep track of which pirq is the first one in the group all
> pirqs in the MSI group except for the first one have the newly
> introduced PIRQ_MSI_GROUP flag set. This prevents calling
> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
> first pirq in the group.

Reviewed-by: David Vrabel <david.vrabel@citrix.com>

David

Re: [Xen-devel] [PATCH] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/26/2014 11:24 AM, Roger Pau Monne wrote:
> Add support for MSI message groups for Xen Dom0 using the
> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>
> In order to keep track of which pirq is the first one in the group all
> pirqs in the MSI group except for the first one have the newly
> introduced PIRQ_MSI_GROUP flag set. This prevents calling
> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
> first pirq in the group.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> ---
> Tested with an Intel ICH8 AHCI SATA controller.
> ---
>   arch/x86/pci/xen.c                   |   29 ++++++++++++++------
>   drivers/xen/events/events_base.c     |   47 +++++++++++++++++++++++-----------
>   drivers/xen/events/events_internal.h |    1 +
>   include/xen/events.h                 |    2 +-
>   include/xen/interface/physdev.h      |    1 +
>   5 files changed, 55 insertions(+), 25 deletions(-)
>
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 103e702..905956f 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   	i = 0;
>   	list_for_each_entry(msidesc, &dev->msi_list, list) {
>   		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
> +					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
>   					       (type == PCI_CAP_ID_MSIX) ?
>   					       "pcifront-msi-x" :
>   					       "pcifront-msi",
> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   				"xen: msi already bound to pirq=%d\n", pirq);
>   		}
>   		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
> +					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
>   					       (type == PCI_CAP_ID_MSIX) ?
>   					       "msi-x" : "msi",
>   					       DOMID_SELF);
> @@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   	int ret = 0;
>   	struct msi_desc *msidesc;
>   
> -	if (type == PCI_CAP_ID_MSI && nvec > 1)
> -		return 1;
> -
>   	list_for_each_entry(msidesc, &dev->msi_list, list) {
>   		struct physdev_map_pirq map_irq;
>   		domid_t domid;
> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   			      (pci_domain_nr(dev->bus) << 16);
>   		map_irq.devfn = dev->devfn;
>   
> -		if (type == PCI_CAP_ID_MSIX) {
> +		if (type == PCI_CAP_ID_MSI && nvec > 1) {
> +			map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
> +			map_irq.entry_nr = nvec;


Are we overloading entry_nr here with a different meaning? I thought it 
was meant to be entry number (in MSI-X table for example), not number of 
entries.


> +		} else if (type == PCI_CAP_ID_MSIX) {
>   			int pos;
>   			u32 table_offset, bir;
>   
> @@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   		if (pci_seg_supported)
>   			ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
>   						    &map_irq);
> +		if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
> +			/*
> +			 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
> +			 * there's nothing else we can do in this case.
> +			 * Just set ret > 0 so driver can retry with
> +			 * single MSI.
> +			 */
> +			ret = 1;
> +			goto out;
> +		}
>   		if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
>   			map_irq.type = MAP_PIRQ_TYPE_MSI;
>   			map_irq.index = -1;
> @@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   			goto out;
>   		}
>   
> -		ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
> -					       map_irq.pirq,
> -					       (type == PCI_CAP_ID_MSIX) ?
> -					       "msi-x" : "msi",
> -						domid);
> +		ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
> +		                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
> +		                               (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
> +		                               domid);
>   		if (ret < 0)
>   			goto out;
>   	}
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index f4a9e33..ff20ae2 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
>   	list_add_tail(&info->list, &xen_irq_list_head);
>   }
>   
> -static int __must_check xen_allocate_irq_dynamic(void)
> +static int __must_check xen_allocate_irqs_dynamic(int nvec)
>   {
>   	int first = 0;
> -	int irq;
> +	int i, irq;
>   
>   #ifdef CONFIG_X86_IO_APIC
>   	/*
> @@ -408,14 +408,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
>   		first = get_nr_irqs_gsi();
>   #endif
>   
> -	irq = irq_alloc_desc_from(first, -1);
> +	irq = irq_alloc_descs_from(first, nvec, -1);
>   
> -	if (irq >= 0)
> -		xen_irq_init(irq);
> +	if (irq >= 0) {
> +		for (i = 0; i < nvec; i++)
> +			xen_irq_init(irq + i);
> +	}
>   
>   	return irq;
>   }
>   
> +static inline int __must_check xen_allocate_irq_dynamic(void)
> +{
> +
> +	return xen_allocate_irqs_dynamic(1);
> +}
> +
>   static int __must_check xen_allocate_irq_gsi(unsigned gsi)
>   {
>   	int irq;
> @@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
>   }
>   
>   int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
> -			     int pirq, const char *name, domid_t domid)
> +			     int pirq, int nvec, const char *name, domid_t domid)
>   {
> -	int irq, ret;
> +	int i, irq, ret;
>   
>   	mutex_lock(&irq_mapping_update_lock);
>   
> -	irq = xen_allocate_irq_dynamic();
> +	irq = xen_allocate_irqs_dynamic(nvec);
>   	if (irq < 0)
>   		goto out;
>   
> -	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
> -			name);
> +	for (i = 0; i < nvec; i++) {
> +		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
> +
> +		ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
> +					      i == 0 ? 0 : PIRQ_MSI_GROUP);
> +		if (ret < 0)
> +			goto error_irq;
> +	}
>   
> -	ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
> -	if (ret < 0)
> -		goto error_irq;
>   	ret = irq_set_msi_desc(irq, msidesc);
>   	if (ret < 0)
>   		goto error_irq;
> @@ -764,7 +775,8 @@ out:
>   	mutex_unlock(&irq_mapping_update_lock);
>   	return irq;
>   error_irq:
> -	__unbind_from_irq(irq);
> +	for (; i >= 0; i--)
> +		__unbind_from_irq(irq + i);
>   	mutex_unlock(&irq_mapping_update_lock);
>   	return ret;
>   }
> @@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
>   	if (!desc)
>   		goto out;
>   
> -	if (xen_initial_domain()) {
> +	/*
> +	 * If trying to remove a vector in a MSI group different
> +	 * than the first one skip the PIRQ unmap unless this vector
> +	 * is the first one in the group.
> +	 */
> +	if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
>   		unmap_irq.pirq = info->u.pirq.pirq;
>   		unmap_irq.domid = info->u.pirq.domid;
>   		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
> diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
> index 677f41a..50c2050a 100644
> --- a/drivers/xen/events/events_internal.h
> +++ b/drivers/xen/events/events_internal.h
> @@ -53,6 +53,7 @@ struct irq_info {
>   
>   #define PIRQ_NEEDS_EOI	(1 << 0)
>   #define PIRQ_SHAREABLE	(1 << 1)
> +#define PIRQ_MSI_GROUP	(1 << 2)
>   
>   struct evtchn_ops {
>   	unsigned (*max_channels)(void);
> diff --git a/include/xen/events.h b/include/xen/events.h
> index c9c85cf..2ae7e03 100644
> --- a/include/xen/events.h
> +++ b/include/xen/events.h
> @@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
>   int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
>   /* Bind an PSI pirq to an irq. */
>   int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
> -			     int pirq, const char *name, domid_t domid);
> +			     int pirq, int nvec, const char *name, domid_t domid);
>   #endif
>   
>   /* De-allocates the above mentioned physical interrupt. */
> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index 42721d1..eb13326d 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -131,6 +131,7 @@ struct physdev_irq {
>   #define MAP_PIRQ_TYPE_GSI		0x1
>   #define MAP_PIRQ_TYPE_UNKNOWN		0x2
>   #define MAP_PIRQ_TYPE_MSI_SEG		0x3
> +#define MAP_PIRQ_TYPE_MULTI_MSI		0x4

Formatting.

-boris

>   
>   #define PHYSDEVOP_map_pirq		13
>   struct physdev_map_pirq {

Re: [PATCH] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/26/2014 11:24 AM, Roger Pau Monne wrote:
> Add support for MSI message groups for Xen Dom0 using the
> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>
> In order to keep track of which pirq is the first one in the group all
> pirqs in the MSI group except for the first one have the newly
> introduced PIRQ_MSI_GROUP flag set. This prevents calling
> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
> first pirq in the group.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
> ---
> Tested with an Intel ICH8 AHCI SATA controller.
> ---
>   arch/x86/pci/xen.c                   |   29 ++++++++++++++------
>   drivers/xen/events/events_base.c     |   47 +++++++++++++++++++++++-----------
>   drivers/xen/events/events_internal.h |    1 +
>   include/xen/events.h                 |    2 +-
>   include/xen/interface/physdev.h      |    1 +
>   5 files changed, 55 insertions(+), 25 deletions(-)
>
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 103e702..905956f 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   	i = 0;
>   	list_for_each_entry(msidesc, &dev->msi_list, list) {
>   		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
> +					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
>   					       (type == PCI_CAP_ID_MSIX) ?
>   					       "pcifront-msi-x" :
>   					       "pcifront-msi",
> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   				"xen: msi already bound to pirq=%d\n", pirq);
>   		}
>   		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
> +					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
>   					       (type == PCI_CAP_ID_MSIX) ?
>   					       "msi-x" : "msi",
>   					       DOMID_SELF);
> @@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   	int ret = 0;
>   	struct msi_desc *msidesc;
>   
> -	if (type == PCI_CAP_ID_MSI && nvec > 1)
> -		return 1;
> -
>   	list_for_each_entry(msidesc, &dev->msi_list, list) {
>   		struct physdev_map_pirq map_irq;
>   		domid_t domid;
> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   			      (pci_domain_nr(dev->bus) << 16);
>   		map_irq.devfn = dev->devfn;
>   
> -		if (type == PCI_CAP_ID_MSIX) {
> +		if (type == PCI_CAP_ID_MSI && nvec > 1) {
> +			map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
> +			map_irq.entry_nr = nvec;


Are we overloading entry_nr here with a different meaning? I thought it 
was meant to be entry number (in MSI-X table for example), not number of 
entries.


> +		} else if (type == PCI_CAP_ID_MSIX) {
>   			int pos;
>   			u32 table_offset, bir;
>   
> @@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   		if (pci_seg_supported)
>   			ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
>   						    &map_irq);
> +		if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
> +			/*
> +			 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
> +			 * there's nothing else we can do in this case.
> +			 * Just set ret > 0 so driver can retry with
> +			 * single MSI.
> +			 */
> +			ret = 1;
> +			goto out;
> +		}
>   		if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
>   			map_irq.type = MAP_PIRQ_TYPE_MSI;
>   			map_irq.index = -1;
> @@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>   			goto out;
>   		}
>   
> -		ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
> -					       map_irq.pirq,
> -					       (type == PCI_CAP_ID_MSIX) ?
> -					       "msi-x" : "msi",
> -						domid);
> +		ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
> +		                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
> +		                               (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
> +		                               domid);
>   		if (ret < 0)
>   			goto out;
>   	}
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index f4a9e33..ff20ae2 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
>   	list_add_tail(&info->list, &xen_irq_list_head);
>   }
>   
> -static int __must_check xen_allocate_irq_dynamic(void)
> +static int __must_check xen_allocate_irqs_dynamic(int nvec)
>   {
>   	int first = 0;
> -	int irq;
> +	int i, irq;
>   
>   #ifdef CONFIG_X86_IO_APIC
>   	/*
> @@ -408,14 +408,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
>   		first = get_nr_irqs_gsi();
>   #endif
>   
> -	irq = irq_alloc_desc_from(first, -1);
> +	irq = irq_alloc_descs_from(first, nvec, -1);
>   
> -	if (irq >= 0)
> -		xen_irq_init(irq);
> +	if (irq >= 0) {
> +		for (i = 0; i < nvec; i++)
> +			xen_irq_init(irq + i);
> +	}
>   
>   	return irq;
>   }
>   
> +static inline int __must_check xen_allocate_irq_dynamic(void)
> +{
> +
> +	return xen_allocate_irqs_dynamic(1);
> +}
> +
>   static int __must_check xen_allocate_irq_gsi(unsigned gsi)
>   {
>   	int irq;
> @@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
>   }
>   
>   int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
> -			     int pirq, const char *name, domid_t domid)
> +			     int pirq, int nvec, const char *name, domid_t domid)
>   {
> -	int irq, ret;
> +	int i, irq, ret;
>   
>   	mutex_lock(&irq_mapping_update_lock);
>   
> -	irq = xen_allocate_irq_dynamic();
> +	irq = xen_allocate_irqs_dynamic(nvec);
>   	if (irq < 0)
>   		goto out;
>   
> -	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
> -			name);
> +	for (i = 0; i < nvec; i++) {
> +		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
> +
> +		ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
> +					      i == 0 ? 0 : PIRQ_MSI_GROUP);
> +		if (ret < 0)
> +			goto error_irq;
> +	}
>   
> -	ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
> -	if (ret < 0)
> -		goto error_irq;
>   	ret = irq_set_msi_desc(irq, msidesc);
>   	if (ret < 0)
>   		goto error_irq;
> @@ -764,7 +775,8 @@ out:
>   	mutex_unlock(&irq_mapping_update_lock);
>   	return irq;
>   error_irq:
> -	__unbind_from_irq(irq);
> +	for (; i >= 0; i--)
> +		__unbind_from_irq(irq + i);
>   	mutex_unlock(&irq_mapping_update_lock);
>   	return ret;
>   }
> @@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
>   	if (!desc)
>   		goto out;
>   
> -	if (xen_initial_domain()) {
> +	/*
> +	 * If trying to remove a vector in a MSI group different
> +	 * than the first one skip the PIRQ unmap unless this vector
> +	 * is the first one in the group.
> +	 */
> +	if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
>   		unmap_irq.pirq = info->u.pirq.pirq;
>   		unmap_irq.domid = info->u.pirq.domid;
>   		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
> diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
> index 677f41a..50c2050a 100644
> --- a/drivers/xen/events/events_internal.h
> +++ b/drivers/xen/events/events_internal.h
> @@ -53,6 +53,7 @@ struct irq_info {
>   
>   #define PIRQ_NEEDS_EOI	(1 << 0)
>   #define PIRQ_SHAREABLE	(1 << 1)
> +#define PIRQ_MSI_GROUP	(1 << 2)
>   
>   struct evtchn_ops {
>   	unsigned (*max_channels)(void);
> diff --git a/include/xen/events.h b/include/xen/events.h
> index c9c85cf..2ae7e03 100644
> --- a/include/xen/events.h
> +++ b/include/xen/events.h
> @@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
>   int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
>   /* Bind an PSI pirq to an irq. */
>   int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
> -			     int pirq, const char *name, domid_t domid);
> +			     int pirq, int nvec, const char *name, domid_t domid);
>   #endif
>   
>   /* De-allocates the above mentioned physical interrupt. */
> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index 42721d1..eb13326d 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -131,6 +131,7 @@ struct physdev_irq {
>   #define MAP_PIRQ_TYPE_GSI		0x1
>   #define MAP_PIRQ_TYPE_UNKNOWN		0x2
>   #define MAP_PIRQ_TYPE_MSI_SEG		0x3
> +#define MAP_PIRQ_TYPE_MULTI_MSI		0x4

Formatting.

-boris

>   
>   #define PHYSDEVOP_map_pirq		13
>   struct physdev_map_pirq {


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Re: [Xen-devel] [PATCH] xen: add support for MSI message groups

[Roger Pau Monné]

On 27/02/14 15:55, Boris Ostrovsky wrote:
> On 02/26/2014 11:24 AM, Roger Pau Monne wrote:
>> Add support for MSI message groups for Xen Dom0 using the
>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>
>> In order to keep track of which pirq is the first one in the group all
>> pirqs in the MSI group except for the first one have the newly
>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>> first pirq in the group.
>>
>> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>> ---
>> Tested with an Intel ICH8 AHCI SATA controller.
>> ---
>>   arch/x86/pci/xen.c                   |   29 ++++++++++++++------
>>   drivers/xen/events/events_base.c     |   47
>> +++++++++++++++++++++++-----------
>>   drivers/xen/events/events_internal.h |    1 +
>>   include/xen/events.h                 |    2 +-
>>   include/xen/interface/physdev.h      |    1 +
>>   5 files changed, 55 insertions(+), 25 deletions(-)
>>
>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>> index 103e702..905956f 100644
>> --- a/arch/x86/pci/xen.c
>> +++ b/arch/x86/pci/xen.c
>> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
>> int nvec, int type)
>>       i = 0;
>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "pcifront-msi-x" :
>>                              "pcifront-msi",
>> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
>> *dev, int nvec, int type)
>>                   "xen: msi already bound to pirq=%d\n", pirq);
>>           }
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "msi-x" : "msi",
>>                              DOMID_SELF);
>> @@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>       int ret = 0;
>>       struct msi_desc *msidesc;
>>   -    if (type == PCI_CAP_ID_MSI && nvec > 1)
>> -        return 1;
>> -
>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>           struct physdev_map_pirq map_irq;
>>           domid_t domid;
>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>                     (pci_domain_nr(dev->bus) << 16);
>>           map_irq.devfn = dev->devfn;
>>   -        if (type == PCI_CAP_ID_MSIX) {
>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>> +            map_irq.entry_nr = nvec;
> 
> 
> Are we overloading entry_nr here with a different meaning? I thought it
> was meant to be entry number (in MSI-X table for example), not number of
> entries.

In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
the number of vectors to setup, so yes, it's an overloading of entry_nr.

> 
>> +        } else if (type == PCI_CAP_ID_MSIX) {
>>               int pos;
>>               u32 table_offset, bir;
>>   @@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>           if (pci_seg_supported)
>>               ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
>>                               &map_irq);
>> +        if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
>> +            /*
>> +             * If MAP_PIRQ_TYPE_MULTI_MSI is not available
>> +             * there's nothing else we can do in this case.
>> +             * Just set ret > 0 so driver can retry with
>> +             * single MSI.
>> +             */
>> +            ret = 1;
>> +            goto out;
>> +        }
>>           if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
>>               map_irq.type = MAP_PIRQ_TYPE_MSI;
>>               map_irq.index = -1;
>> @@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>               goto out;
>>           }
>>   -        ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
>> -                           map_irq.pirq,
>> -                           (type == PCI_CAP_ID_MSIX) ?
>> -                           "msi-x" : "msi",
>> -                        domid);
>> +        ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
>> +                                       (type == PCI_CAP_ID_MSI) ?
>> nvec : 1,
>> +                                       (type == PCI_CAP_ID_MSIX) ?
>> "msi-x" : "msi",
>> +                                       domid);
>>           if (ret < 0)
>>               goto out;
>>       }
>> diff --git a/drivers/xen/events/events_base.c
>> b/drivers/xen/events/events_base.c
>> index f4a9e33..ff20ae2 100644
>> --- a/drivers/xen/events/events_base.c
>> +++ b/drivers/xen/events/events_base.c
>> @@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
>>       list_add_tail(&info->list, &xen_irq_list_head);
>>   }
>>   -static int __must_check xen_allocate_irq_dynamic(void)
>> +static int __must_check xen_allocate_irqs_dynamic(int nvec)
>>   {
>>       int first = 0;
>> -    int irq;
>> +    int i, irq;
>>     #ifdef CONFIG_X86_IO_APIC
>>       /*
>> @@ -408,14 +408,22 @@ static int __must_check
>> xen_allocate_irq_dynamic(void)
>>           first = get_nr_irqs_gsi();
>>   #endif
>>   -    irq = irq_alloc_desc_from(first, -1);
>> +    irq = irq_alloc_descs_from(first, nvec, -1);
>>   -    if (irq >= 0)
>> -        xen_irq_init(irq);
>> +    if (irq >= 0) {
>> +        for (i = 0; i < nvec; i++)
>> +            xen_irq_init(irq + i);
>> +    }
>>         return irq;
>>   }
>>   +static inline int __must_check xen_allocate_irq_dynamic(void)
>> +{
>> +
>> +    return xen_allocate_irqs_dynamic(1);
>> +}
>> +
>>   static int __must_check xen_allocate_irq_gsi(unsigned gsi)
>>   {
>>       int irq;
>> @@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev,
>> struct msi_desc *msidesc)
>>   }
>>     int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc
>> *msidesc,
>> -                 int pirq, const char *name, domid_t domid)
>> +                 int pirq, int nvec, const char *name, domid_t domid)
>>   {
>> -    int irq, ret;
>> +    int i, irq, ret;
>>         mutex_lock(&irq_mapping_update_lock);
>>   -    irq = xen_allocate_irq_dynamic();
>> +    irq = xen_allocate_irqs_dynamic(nvec);
>>       if (irq < 0)
>>           goto out;
>>   -    irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
>> handle_edge_irq,
>> -            name);
>> +    for (i = 0; i < nvec; i++) {
>> +        irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip,
>> handle_edge_irq, name);
>> +
>> +        ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
>> +                          i == 0 ? 0 : PIRQ_MSI_GROUP);
>> +        if (ret < 0)
>> +            goto error_irq;
>> +    }
>>   -    ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
>> -    if (ret < 0)
>> -        goto error_irq;
>>       ret = irq_set_msi_desc(irq, msidesc);
>>       if (ret < 0)
>>           goto error_irq;
>> @@ -764,7 +775,8 @@ out:
>>       mutex_unlock(&irq_mapping_update_lock);
>>       return irq;
>>   error_irq:
>> -    __unbind_from_irq(irq);
>> +    for (; i >= 0; i--)
>> +        __unbind_from_irq(irq + i);
>>       mutex_unlock(&irq_mapping_update_lock);
>>       return ret;
>>   }
>> @@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
>>       if (!desc)
>>           goto out;
>>   -    if (xen_initial_domain()) {
>> +    /*
>> +     * If trying to remove a vector in a MSI group different
>> +     * than the first one skip the PIRQ unmap unless this vector
>> +     * is the first one in the group.
>> +     */
>> +    if (xen_initial_domain() && !(info->u.pirq.flags &
>> PIRQ_MSI_GROUP)) {
>>           unmap_irq.pirq = info->u.pirq.pirq;
>>           unmap_irq.domid = info->u.pirq.domid;
>>           rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
>> diff --git a/drivers/xen/events/events_internal.h
>> b/drivers/xen/events/events_internal.h
>> index 677f41a..50c2050a 100644
>> --- a/drivers/xen/events/events_internal.h
>> +++ b/drivers/xen/events/events_internal.h
>> @@ -53,6 +53,7 @@ struct irq_info {
>>     #define PIRQ_NEEDS_EOI    (1 << 0)
>>   #define PIRQ_SHAREABLE    (1 << 1)
>> +#define PIRQ_MSI_GROUP    (1 << 2)
>>     struct evtchn_ops {
>>       unsigned (*max_channels)(void);
>> diff --git a/include/xen/events.h b/include/xen/events.h
>> index c9c85cf..2ae7e03 100644
>> --- a/include/xen/events.h
>> +++ b/include/xen/events.h
>> @@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
>>   int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc
>> *msidesc);
>>   /* Bind an PSI pirq to an irq. */
>>   int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc
>> *msidesc,
>> -                 int pirq, const char *name, domid_t domid);
>> +                 int pirq, int nvec, const char *name, domid_t domid);
>>   #endif
>>     /* De-allocates the above mentioned physical interrupt. */
>> diff --git a/include/xen/interface/physdev.h
>> b/include/xen/interface/physdev.h
>> index 42721d1..eb13326d 100644
>> --- a/include/xen/interface/physdev.h
>> +++ b/include/xen/interface/physdev.h
>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>   #define MAP_PIRQ_TYPE_GSI        0x1
>>   #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>   #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
> 
> Formatting.

I don't get the formatting problem, it's the same formatting that the
other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.

Re: [PATCH] xen: add support for MSI message groups

[Roger Pau Monné]

On 27/02/14 15:55, Boris Ostrovsky wrote:
> On 02/26/2014 11:24 AM, Roger Pau Monne wrote:
>> Add support for MSI message groups for Xen Dom0 using the
>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>
>> In order to keep track of which pirq is the first one in the group all
>> pirqs in the MSI group except for the first one have the newly
>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>> first pirq in the group.
>>
>> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
>> ---
>> Tested with an Intel ICH8 AHCI SATA controller.
>> ---
>>   arch/x86/pci/xen.c                   |   29 ++++++++++++++------
>>   drivers/xen/events/events_base.c     |   47
>> +++++++++++++++++++++++-----------
>>   drivers/xen/events/events_internal.h |    1 +
>>   include/xen/events.h                 |    2 +-
>>   include/xen/interface/physdev.h      |    1 +
>>   5 files changed, 55 insertions(+), 25 deletions(-)
>>
>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>> index 103e702..905956f 100644
>> --- a/arch/x86/pci/xen.c
>> +++ b/arch/x86/pci/xen.c
>> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
>> int nvec, int type)
>>       i = 0;
>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "pcifront-msi-x" :
>>                              "pcifront-msi",
>> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
>> *dev, int nvec, int type)
>>                   "xen: msi already bound to pirq=%d\n", pirq);
>>           }
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "msi-x" : "msi",
>>                              DOMID_SELF);
>> @@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>       int ret = 0;
>>       struct msi_desc *msidesc;
>>   -    if (type == PCI_CAP_ID_MSI && nvec > 1)
>> -        return 1;
>> -
>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>           struct physdev_map_pirq map_irq;
>>           domid_t domid;
>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>                     (pci_domain_nr(dev->bus) << 16);
>>           map_irq.devfn = dev->devfn;
>>   -        if (type == PCI_CAP_ID_MSIX) {
>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>> +            map_irq.entry_nr = nvec;
> 
> 
> Are we overloading entry_nr here with a different meaning? I thought it
> was meant to be entry number (in MSI-X table for example), not number of
> entries.

In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
the number of vectors to setup, so yes, it's an overloading of entry_nr.

> 
>> +        } else if (type == PCI_CAP_ID_MSIX) {
>>               int pos;
>>               u32 table_offset, bir;
>>   @@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>           if (pci_seg_supported)
>>               ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
>>                               &map_irq);
>> +        if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
>> +            /*
>> +             * If MAP_PIRQ_TYPE_MULTI_MSI is not available
>> +             * there's nothing else we can do in this case.
>> +             * Just set ret > 0 so driver can retry with
>> +             * single MSI.
>> +             */
>> +            ret = 1;
>> +            goto out;
>> +        }
>>           if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
>>               map_irq.type = MAP_PIRQ_TYPE_MSI;
>>               map_irq.index = -1;
>> @@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>               goto out;
>>           }
>>   -        ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
>> -                           map_irq.pirq,
>> -                           (type == PCI_CAP_ID_MSIX) ?
>> -                           "msi-x" : "msi",
>> -                        domid);
>> +        ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
>> +                                       (type == PCI_CAP_ID_MSI) ?
>> nvec : 1,
>> +                                       (type == PCI_CAP_ID_MSIX) ?
>> "msi-x" : "msi",
>> +                                       domid);
>>           if (ret < 0)
>>               goto out;
>>       }
>> diff --git a/drivers/xen/events/events_base.c
>> b/drivers/xen/events/events_base.c
>> index f4a9e33..ff20ae2 100644
>> --- a/drivers/xen/events/events_base.c
>> +++ b/drivers/xen/events/events_base.c
>> @@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
>>       list_add_tail(&info->list, &xen_irq_list_head);
>>   }
>>   -static int __must_check xen_allocate_irq_dynamic(void)
>> +static int __must_check xen_allocate_irqs_dynamic(int nvec)
>>   {
>>       int first = 0;
>> -    int irq;
>> +    int i, irq;
>>     #ifdef CONFIG_X86_IO_APIC
>>       /*
>> @@ -408,14 +408,22 @@ static int __must_check
>> xen_allocate_irq_dynamic(void)
>>           first = get_nr_irqs_gsi();
>>   #endif
>>   -    irq = irq_alloc_desc_from(first, -1);
>> +    irq = irq_alloc_descs_from(first, nvec, -1);
>>   -    if (irq >= 0)
>> -        xen_irq_init(irq);
>> +    if (irq >= 0) {
>> +        for (i = 0; i < nvec; i++)
>> +            xen_irq_init(irq + i);
>> +    }
>>         return irq;
>>   }
>>   +static inline int __must_check xen_allocate_irq_dynamic(void)
>> +{
>> +
>> +    return xen_allocate_irqs_dynamic(1);
>> +}
>> +
>>   static int __must_check xen_allocate_irq_gsi(unsigned gsi)
>>   {
>>       int irq;
>> @@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev,
>> struct msi_desc *msidesc)
>>   }
>>     int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc
>> *msidesc,
>> -                 int pirq, const char *name, domid_t domid)
>> +                 int pirq, int nvec, const char *name, domid_t domid)
>>   {
>> -    int irq, ret;
>> +    int i, irq, ret;
>>         mutex_lock(&irq_mapping_update_lock);
>>   -    irq = xen_allocate_irq_dynamic();
>> +    irq = xen_allocate_irqs_dynamic(nvec);
>>       if (irq < 0)
>>           goto out;
>>   -    irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
>> handle_edge_irq,
>> -            name);
>> +    for (i = 0; i < nvec; i++) {
>> +        irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip,
>> handle_edge_irq, name);
>> +
>> +        ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
>> +                          i == 0 ? 0 : PIRQ_MSI_GROUP);
>> +        if (ret < 0)
>> +            goto error_irq;
>> +    }
>>   -    ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
>> -    if (ret < 0)
>> -        goto error_irq;
>>       ret = irq_set_msi_desc(irq, msidesc);
>>       if (ret < 0)
>>           goto error_irq;
>> @@ -764,7 +775,8 @@ out:
>>       mutex_unlock(&irq_mapping_update_lock);
>>       return irq;
>>   error_irq:
>> -    __unbind_from_irq(irq);
>> +    for (; i >= 0; i--)
>> +        __unbind_from_irq(irq + i);
>>       mutex_unlock(&irq_mapping_update_lock);
>>       return ret;
>>   }
>> @@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
>>       if (!desc)
>>           goto out;
>>   -    if (xen_initial_domain()) {
>> +    /*
>> +     * If trying to remove a vector in a MSI group different
>> +     * than the first one skip the PIRQ unmap unless this vector
>> +     * is the first one in the group.
>> +     */
>> +    if (xen_initial_domain() && !(info->u.pirq.flags &
>> PIRQ_MSI_GROUP)) {
>>           unmap_irq.pirq = info->u.pirq.pirq;
>>           unmap_irq.domid = info->u.pirq.domid;
>>           rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
>> diff --git a/drivers/xen/events/events_internal.h
>> b/drivers/xen/events/events_internal.h
>> index 677f41a..50c2050a 100644
>> --- a/drivers/xen/events/events_internal.h
>> +++ b/drivers/xen/events/events_internal.h
>> @@ -53,6 +53,7 @@ struct irq_info {
>>     #define PIRQ_NEEDS_EOI    (1 << 0)
>>   #define PIRQ_SHAREABLE    (1 << 1)
>> +#define PIRQ_MSI_GROUP    (1 << 2)
>>     struct evtchn_ops {
>>       unsigned (*max_channels)(void);
>> diff --git a/include/xen/events.h b/include/xen/events.h
>> index c9c85cf..2ae7e03 100644
>> --- a/include/xen/events.h
>> +++ b/include/xen/events.h
>> @@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
>>   int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc
>> *msidesc);
>>   /* Bind an PSI pirq to an irq. */
>>   int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc
>> *msidesc,
>> -                 int pirq, const char *name, domid_t domid);
>> +                 int pirq, int nvec, const char *name, domid_t domid);
>>   #endif
>>     /* De-allocates the above mentioned physical interrupt. */
>> diff --git a/include/xen/interface/physdev.h
>> b/include/xen/interface/physdev.h
>> index 42721d1..eb13326d 100644
>> --- a/include/xen/interface/physdev.h
>> +++ b/include/xen/interface/physdev.h
>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>   #define MAP_PIRQ_TYPE_GSI        0x1
>>   #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>   #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
> 
> Formatting.

I don't get the formatting problem, it's the same formatting that the
other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.


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Re: [Xen-devel] [PATCH] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/27/2014 10:45 AM, Roger Pau Monné wrote:
>>
>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>                      (pci_domain_nr(dev->bus) << 16);
>>            map_irq.devfn = dev->devfn;
>>    -        if (type == PCI_CAP_ID_MSIX) {
>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>> +            map_irq.entry_nr = nvec;
>>
>> Are we overloading entry_nr here with a different meaning? I thought it
>> was meant to be entry number (in MSI-X table for example), not number of
>> entries.
> In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
> the number of vectors to setup, so yes, it's an overloading of entry_nr.

Then I think we should at least make a note of this in physdev.h. (Or 
maybe even make entry_nr a union with nvec or some such, although that 
would look rather hacky).

> ....
>
>>
>> index 42721d1..eb13326d 100644
>> --- a/include/xen/interface/physdev.h
>> +++ b/include/xen/interface/physdev.h
>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>    #define MAP_PIRQ_TYPE_GSI        0x1
>>    #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>    #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
>> Formatting.
> I don't get the formatting problem, it's the same formatting that the
> other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.
>

That's because my client messed up whitespaces. You can look for example 
at https://lkml.org/lkml/2014/2/26/352 to see the extra tab.

-boris

Re: [PATCH] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/27/2014 10:45 AM, Roger Pau Monné wrote:
>>
>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>> pci_dev *dev, int nvec, int type)
>>                      (pci_domain_nr(dev->bus) << 16);
>>            map_irq.devfn = dev->devfn;
>>    -        if (type == PCI_CAP_ID_MSIX) {
>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>> +            map_irq.entry_nr = nvec;
>>
>> Are we overloading entry_nr here with a different meaning? I thought it
>> was meant to be entry number (in MSI-X table for example), not number of
>> entries.
> In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
> the number of vectors to setup, so yes, it's an overloading of entry_nr.

Then I think we should at least make a note of this in physdev.h. (Or 
maybe even make entry_nr a union with nvec or some such, although that 
would look rather hacky).

> ....
>
>>
>> index 42721d1..eb13326d 100644
>> --- a/include/xen/interface/physdev.h
>> +++ b/include/xen/interface/physdev.h
>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>    #define MAP_PIRQ_TYPE_GSI        0x1
>>    #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>    #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
>> Formatting.
> I don't get the formatting problem, it's the same formatting that the
> other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.
>

That's because my client messed up whitespaces. You can look for example 
at https://lkml.org/lkml/2014/2/26/352 to see the extra tab.

-boris

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Re: [Xen-devel] [PATCH] xen: add support for MSI message groups

[Roger Pau Monné]

On 27/02/14 17:33, Boris Ostrovsky wrote:
> On 02/27/2014 10:45 AM, Roger Pau Monné wrote:
>>>
>>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>>> pci_dev *dev, int nvec, int type)
>>>                      (pci_domain_nr(dev->bus) << 16);
>>>            map_irq.devfn = dev->devfn;
>>>    -        if (type == PCI_CAP_ID_MSIX) {
>>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>>> +            map_irq.entry_nr = nvec;
>>>
>>> Are we overloading entry_nr here with a different meaning? I thought it
>>> was meant to be entry number (in MSI-X table for example), not number of
>>> entries.
>> In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
>> the number of vectors to setup, so yes, it's an overloading of entry_nr.
> 
> Then I think we should at least make a note of this in physdev.h. (Or
> maybe even make entry_nr a union with nvec or some such, although that
> would look rather hacky).

OK, I can add a comment to that effect in physdev.h.

> 
>> ....
>>
>>>
>>> index 42721d1..eb13326d 100644
>>> --- a/include/xen/interface/physdev.h
>>> +++ b/include/xen/interface/physdev.h
>>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>>    #define MAP_PIRQ_TYPE_GSI        0x1
>>>    #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>>    #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
>>> Formatting.
>> I don't get the formatting problem, it's the same formatting that the
>> other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.
>>
> 
> That's because my client messed up whitespaces. You can look for example
> at https://lkml.org/lkml/2014/2/26/352 to see the extra tab.

It looks like an extra tab because there's a "+" in front of the line,
which makes the tab jump. If you remove the extra "+" and the spaces in
front of the preceding lines it is going to be aligned.

Roger.

Re: [PATCH] xen: add support for MSI message groups

[Roger Pau Monné]

On 27/02/14 17:33, Boris Ostrovsky wrote:
> On 02/27/2014 10:45 AM, Roger Pau Monné wrote:
>>>
>>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>>> pci_dev *dev, int nvec, int type)
>>>                      (pci_domain_nr(dev->bus) << 16);
>>>            map_irq.devfn = dev->devfn;
>>>    -        if (type == PCI_CAP_ID_MSIX) {
>>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>>> +            map_irq.entry_nr = nvec;
>>>
>>> Are we overloading entry_nr here with a different meaning? I thought it
>>> was meant to be entry number (in MSI-X table for example), not number of
>>> entries.
>> In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
>> the number of vectors to setup, so yes, it's an overloading of entry_nr.
> 
> Then I think we should at least make a note of this in physdev.h. (Or
> maybe even make entry_nr a union with nvec or some such, although that
> would look rather hacky).

OK, I can add a comment to that effect in physdev.h.

> 
>> ....
>>
>>>
>>> index 42721d1..eb13326d 100644
>>> --- a/include/xen/interface/physdev.h
>>> +++ b/include/xen/interface/physdev.h
>>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>>    #define MAP_PIRQ_TYPE_GSI        0x1
>>>    #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>>    #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
>>> Formatting.
>> I don't get the formatting problem, it's the same formatting that the
>> other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.
>>
> 
> That's because my client messed up whitespaces. You can look for example
> at https://lkml.org/lkml/2014/2/26/352 to see the extra tab.

It looks like an extra tab because there's a "+" in front of the line,
which makes the tab jump. If you remove the extra "+" and the spaces in
front of the preceding lines it is going to be aligned.

Roger.

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[PATCH v2] xen: add support for MSI message groups

[Roger Pau Monne]

Add support for MSI message groups for Xen Dom0 using the
MAP_PIRQ_TYPE_MULTI_MSI pirq map type.

In order to keep track of which pirq is the first one in the group all
pirqs in the MSI group except for the first one have the newly
introduced PIRQ_MSI_GROUP flag set. This prevents calling
PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
first pirq in the group.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
Tested with an Intel ICH8 AHCI SATA controller.
---
Changes since v1:
 - Add comments reflecting the new usage of entry_nr in
   physdev_map_pirq.
---
 arch/x86/pci/xen.c                   |   29 ++++++++++++++------
 drivers/xen/events/events_base.c     |   47 +++++++++++++++++++++++-----------
 drivers/xen/events/events_internal.h |    1 +
 include/xen/events.h                 |    2 +-
 include/xen/interface/physdev.h      |   10 ++++++-
 5 files changed, 62 insertions(+), 27 deletions(-)

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702..905956f 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	i = 0;
 	list_for_each_entry(msidesc, &dev->msi_list, list) {
 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
 					       (type == PCI_CAP_ID_MSIX) ?
 					       "pcifront-msi-x" :
 					       "pcifront-msi",
@@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 				"xen: msi already bound to pirq=%d\n", pirq);
 		}
 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
 					       (type == PCI_CAP_ID_MSIX) ?
 					       "msi-x" : "msi",
 					       DOMID_SELF);
@@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	int ret = 0;
 	struct msi_desc *msidesc;
 
-	if (type == PCI_CAP_ID_MSI && nvec > 1)
-		return 1;
-
 	list_for_each_entry(msidesc, &dev->msi_list, list) {
 		struct physdev_map_pirq map_irq;
 		domid_t domid;
@@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 			      (pci_domain_nr(dev->bus) << 16);
 		map_irq.devfn = dev->devfn;
 
-		if (type == PCI_CAP_ID_MSIX) {
+		if (type == PCI_CAP_ID_MSI && nvec > 1) {
+			map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
+			map_irq.entry_nr = nvec;
+		} else if (type == PCI_CAP_ID_MSIX) {
 			int pos;
 			u32 table_offset, bir;
 
@@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 		if (pci_seg_supported)
 			ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
 						    &map_irq);
+		if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
+			/*
+			 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
+			 * there's nothing else we can do in this case.
+			 * Just set ret > 0 so driver can retry with
+			 * single MSI.
+			 */
+			ret = 1;
+			goto out;
+		}
 		if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
 			map_irq.type = MAP_PIRQ_TYPE_MSI;
 			map_irq.index = -1;
@@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 			goto out;
 		}
 
-		ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
-					       map_irq.pirq,
-					       (type == PCI_CAP_ID_MSIX) ?
-					       "msi-x" : "msi",
-						domid);
+		ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
+		                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
+		                               (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
+		                               domid);
 		if (ret < 0)
 			goto out;
 	}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index f4a9e33..ff20ae2 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
-static int __must_check xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irqs_dynamic(int nvec)
 {
 	int first = 0;
-	int irq;
+	int i, irq;
 
 #ifdef CONFIG_X86_IO_APIC
 	/*
@@ -408,14 +408,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
 		first = get_nr_irqs_gsi();
 #endif
 
-	irq = irq_alloc_desc_from(first, -1);
+	irq = irq_alloc_descs_from(first, nvec, -1);
 
-	if (irq >= 0)
-		xen_irq_init(irq);
+	if (irq >= 0) {
+		for (i = 0; i < nvec; i++)
+			xen_irq_init(irq + i);
+	}
 
 	return irq;
 }
 
+static inline int __must_check xen_allocate_irq_dynamic(void)
+{
+
+	return xen_allocate_irqs_dynamic(1);
+}
+
 static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 {
 	int irq;
@@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
 }
 
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid)
+			     int pirq, int nvec, const char *name, domid_t domid)
 {
-	int irq, ret;
+	int i, irq, ret;
 
 	mutex_lock(&irq_mapping_update_lock);
 
-	irq = xen_allocate_irq_dynamic();
+	irq = xen_allocate_irqs_dynamic(nvec);
 	if (irq < 0)
 		goto out;
 
-	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
-			name);
+	for (i = 0; i < nvec; i++) {
+		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+
+		ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
+					      i == 0 ? 0 : PIRQ_MSI_GROUP);
+		if (ret < 0)
+			goto error_irq;
+	}
 
-	ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
-	if (ret < 0)
-		goto error_irq;
 	ret = irq_set_msi_desc(irq, msidesc);
 	if (ret < 0)
 		goto error_irq;
@@ -764,7 +775,8 @@ out:
 	mutex_unlock(&irq_mapping_update_lock);
 	return irq;
 error_irq:
-	__unbind_from_irq(irq);
+	for (; i >= 0; i--)
+		__unbind_from_irq(irq + i);
 	mutex_unlock(&irq_mapping_update_lock);
 	return ret;
 }
@@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
 	if (!desc)
 		goto out;
 
-	if (xen_initial_domain()) {
+	/*
+	 * If trying to remove a vector in a MSI group different
+	 * than the first one skip the PIRQ unmap unless this vector
+	 * is the first one in the group.
+	 */
+	if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
 		unmap_irq.pirq = info->u.pirq.pirq;
 		unmap_irq.domid = info->u.pirq.domid;
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 677f41a..50c2050a 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -53,6 +53,7 @@ struct irq_info {
 
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
+#define PIRQ_MSI_GROUP	(1 << 2)
 
 struct evtchn_ops {
 	unsigned (*max_channels)(void);
diff --git a/include/xen/events.h b/include/xen/events.h
index c9c85cf..2ae7e03 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
 /* Bind an PSI pirq to an irq. */
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid);
+			     int pirq, int nvec, const char *name, domid_t domid);
 #endif
 
 /* De-allocates the above mentioned physical interrupt. */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 42721d1..610dba9 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -131,6 +131,7 @@ struct physdev_irq {
 #define MAP_PIRQ_TYPE_GSI		0x1
 #define MAP_PIRQ_TYPE_UNKNOWN		0x2
 #define MAP_PIRQ_TYPE_MSI_SEG		0x3
+#define MAP_PIRQ_TYPE_MULTI_MSI		0x4
 
 #define PHYSDEVOP_map_pirq		13
 struct physdev_map_pirq {
@@ -141,11 +142,16 @@ struct physdev_map_pirq {
     int index;
     /* IN or OUT */
     int pirq;
-    /* IN - high 16 bits hold segment for MAP_PIRQ_TYPE_MSI_SEG */
+    /* IN - high 16 bits hold segment for ..._MSI_SEG and ..._MULTI_MSI */
     int bus;
     /* IN */
     int devfn;
-    /* IN */
+    /* IN
+     * - For MSI-X contains entry number.
+     * - For MSI with ..._MULTI_MSI contains number of vectors.
+     * OUT (..._MULTI_MSI only)
+     * - Number of vectors allocated.
+     */
     int entry_nr;
     /* IN */
     uint64_t table_base;
-- 
1.7.7.5 (Apple Git-26)

[PATCH v2] xen: add support for MSI message groups

[Roger Pau Monne]

Add support for MSI message groups for Xen Dom0 using the
MAP_PIRQ_TYPE_MULTI_MSI pirq map type.

In order to keep track of which pirq is the first one in the group all
pirqs in the MSI group except for the first one have the newly
introduced PIRQ_MSI_GROUP flag set. This prevents calling
PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
first pirq in the group.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
Tested with an Intel ICH8 AHCI SATA controller.
---
Changes since v1:
 - Add comments reflecting the new usage of entry_nr in
   physdev_map_pirq.
---
 arch/x86/pci/xen.c                   |   29 ++++++++++++++------
 drivers/xen/events/events_base.c     |   47 +++++++++++++++++++++++-----------
 drivers/xen/events/events_internal.h |    1 +
 include/xen/events.h                 |    2 +-
 include/xen/interface/physdev.h      |   10 ++++++-
 5 files changed, 62 insertions(+), 27 deletions(-)

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702..905956f 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	i = 0;
 	list_for_each_entry(msidesc, &dev->msi_list, list) {
 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
 					       (type == PCI_CAP_ID_MSIX) ?
 					       "pcifront-msi-x" :
 					       "pcifront-msi",
@@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 				"xen: msi already bound to pirq=%d\n", pirq);
 		}
 		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
 					       (type == PCI_CAP_ID_MSIX) ?
 					       "msi-x" : "msi",
 					       DOMID_SELF);
@@ -269,9 +271,6 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	int ret = 0;
 	struct msi_desc *msidesc;
 
-	if (type == PCI_CAP_ID_MSI && nvec > 1)
-		return 1;
-
 	list_for_each_entry(msidesc, &dev->msi_list, list) {
 		struct physdev_map_pirq map_irq;
 		domid_t domid;
@@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 			      (pci_domain_nr(dev->bus) << 16);
 		map_irq.devfn = dev->devfn;
 
-		if (type == PCI_CAP_ID_MSIX) {
+		if (type == PCI_CAP_ID_MSI && nvec > 1) {
+			map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
+			map_irq.entry_nr = nvec;
+		} else if (type == PCI_CAP_ID_MSIX) {
 			int pos;
 			u32 table_offset, bir;
 
@@ -308,6 +310,16 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 		if (pci_seg_supported)
 			ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
 						    &map_irq);
+		if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
+			/*
+			 * If MAP_PIRQ_TYPE_MULTI_MSI is not available
+			 * there's nothing else we can do in this case.
+			 * Just set ret > 0 so driver can retry with
+			 * single MSI.
+			 */
+			ret = 1;
+			goto out;
+		}
 		if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
 			map_irq.type = MAP_PIRQ_TYPE_MSI;
 			map_irq.index = -1;
@@ -324,11 +336,10 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 			goto out;
 		}
 
-		ret = xen_bind_pirq_msi_to_irq(dev, msidesc,
-					       map_irq.pirq,
-					       (type == PCI_CAP_ID_MSIX) ?
-					       "msi-x" : "msi",
-						domid);
+		ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
+		                               (type == PCI_CAP_ID_MSI) ? nvec : 1,
+		                               (type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
+		                               domid);
 		if (ret < 0)
 			goto out;
 	}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index f4a9e33..ff20ae2 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -391,10 +391,10 @@ static void xen_irq_init(unsigned irq)
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
-static int __must_check xen_allocate_irq_dynamic(void)
+static int __must_check xen_allocate_irqs_dynamic(int nvec)
 {
 	int first = 0;
-	int irq;
+	int i, irq;
 
 #ifdef CONFIG_X86_IO_APIC
 	/*
@@ -408,14 +408,22 @@ static int __must_check xen_allocate_irq_dynamic(void)
 		first = get_nr_irqs_gsi();
 #endif
 
-	irq = irq_alloc_desc_from(first, -1);
+	irq = irq_alloc_descs_from(first, nvec, -1);
 
-	if (irq >= 0)
-		xen_irq_init(irq);
+	if (irq >= 0) {
+		for (i = 0; i < nvec; i++)
+			xen_irq_init(irq + i);
+	}
 
 	return irq;
 }
 
+static inline int __must_check xen_allocate_irq_dynamic(void)
+{
+
+	return xen_allocate_irqs_dynamic(1);
+}
+
 static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 {
 	int irq;
@@ -741,22 +749,25 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
 }
 
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid)
+			     int pirq, int nvec, const char *name, domid_t domid)
 {
-	int irq, ret;
+	int i, irq, ret;
 
 	mutex_lock(&irq_mapping_update_lock);
 
-	irq = xen_allocate_irq_dynamic();
+	irq = xen_allocate_irqs_dynamic(nvec);
 	if (irq < 0)
 		goto out;
 
-	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
-			name);
+	for (i = 0; i < nvec; i++) {
+		irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+
+		ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
+					      i == 0 ? 0 : PIRQ_MSI_GROUP);
+		if (ret < 0)
+			goto error_irq;
+	}
 
-	ret = xen_irq_info_pirq_setup(irq, 0, pirq, 0, domid, 0);
-	if (ret < 0)
-		goto error_irq;
 	ret = irq_set_msi_desc(irq, msidesc);
 	if (ret < 0)
 		goto error_irq;
@@ -764,7 +775,8 @@ out:
 	mutex_unlock(&irq_mapping_update_lock);
 	return irq;
 error_irq:
-	__unbind_from_irq(irq);
+	for (; i >= 0; i--)
+		__unbind_from_irq(irq + i);
 	mutex_unlock(&irq_mapping_update_lock);
 	return ret;
 }
@@ -783,7 +795,12 @@ int xen_destroy_irq(int irq)
 	if (!desc)
 		goto out;
 
-	if (xen_initial_domain()) {
+	/*
+	 * If trying to remove a vector in a MSI group different
+	 * than the first one skip the PIRQ unmap unless this vector
+	 * is the first one in the group.
+	 */
+	if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
 		unmap_irq.pirq = info->u.pirq.pirq;
 		unmap_irq.domid = info->u.pirq.domid;
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 677f41a..50c2050a 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -53,6 +53,7 @@ struct irq_info {
 
 #define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
+#define PIRQ_MSI_GROUP	(1 << 2)
 
 struct evtchn_ops {
 	unsigned (*max_channels)(void);
diff --git a/include/xen/events.h b/include/xen/events.h
index c9c85cf..2ae7e03 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -102,7 +102,7 @@ int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
 /* Bind an PSI pirq to an irq. */
 int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
-			     int pirq, const char *name, domid_t domid);
+			     int pirq, int nvec, const char *name, domid_t domid);
 #endif
 
 /* De-allocates the above mentioned physical interrupt. */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 42721d1..610dba9 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -131,6 +131,7 @@ struct physdev_irq {
 #define MAP_PIRQ_TYPE_GSI		0x1
 #define MAP_PIRQ_TYPE_UNKNOWN		0x2
 #define MAP_PIRQ_TYPE_MSI_SEG		0x3
+#define MAP_PIRQ_TYPE_MULTI_MSI		0x4
 
 #define PHYSDEVOP_map_pirq		13
 struct physdev_map_pirq {
@@ -141,11 +142,16 @@ struct physdev_map_pirq {
     int index;
     /* IN or OUT */
     int pirq;
-    /* IN - high 16 bits hold segment for MAP_PIRQ_TYPE_MSI_SEG */
+    /* IN - high 16 bits hold segment for ..._MSI_SEG and ..._MULTI_MSI */
     int bus;
     /* IN */
     int devfn;
-    /* IN */
+    /* IN
+     * - For MSI-X contains entry number.
+     * - For MSI with ..._MULTI_MSI contains number of vectors.
+     * OUT (..._MULTI_MSI only)
+     * - Number of vectors allocated.
+     */
     int entry_nr;
     /* IN */
     uint64_t table_base;
-- 
1.7.7.5 (Apple Git-26)


_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
> Add support for MSI message groups for Xen Dom0 using the
> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>
> In order to keep track of which pirq is the first one in the group all
> pirqs in the MSI group except for the first one have the newly
> introduced PIRQ_MSI_GROUP flag set. This prevents calling
> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
> first pirq in the group.

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
> Add support for MSI message groups for Xen Dom0 using the
> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>
> In order to keep track of which pirq is the first one in the group all
> pirqs in the MSI group except for the first one have the newly
> introduced PIRQ_MSI_GROUP flag set. This prevents calling
> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
> first pirq in the group.

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>> Add support for MSI message groups for Xen Dom0 using the
>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>
>> In order to keep track of which pirq is the first one in the group all
>> pirqs in the MSI group except for the first one have the newly
>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>> first pirq in the group.
>
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>
>


I was just looking at xen_setup_msi_irqs() (for a different reason) and 
I am no longer sure this patch does anything:

static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
         int irq, ret, i;
         struct msi_desc *msidesc;
         int *v;

         if (type == PCI_CAP_ID_MSI && nvec > 1)
                 return 1;
....

Same thing for xen_hvm_setup_msi_irqs().

Take a look at commit 884ac2978a295b7df3c4a686d3bff6932bbbb460.


-boris

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>> Add support for MSI message groups for Xen Dom0 using the
>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>
>> In order to keep track of which pirq is the first one in the group all
>> pirqs in the MSI group except for the first one have the newly
>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>> first pirq in the group.
>
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>
>


I was just looking at xen_setup_msi_irqs() (for a different reason) and 
I am no longer sure this patch does anything:

static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
         int irq, ret, i;
         struct msi_desc *msidesc;
         int *v;

         if (type == PCI_CAP_ID_MSI && nvec > 1)
                 return 1;
....

Same thing for xen_hvm_setup_msi_irqs().

Take a look at commit 884ac2978a295b7df3c4a686d3bff6932bbbb460.


-boris

Re: [PATCH v2] xen: add support for MSI message groups

[Roger Pau Monné]

On 28/02/14 18:20, Boris Ostrovsky wrote:
> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>> Add support for MSI message groups for Xen Dom0 using the
>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>
>>> In order to keep track of which pirq is the first one in the group all
>>> pirqs in the MSI group except for the first one have the newly
>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>> first pirq in the group.
>>
>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>
>>
> 
> 
> I was just looking at xen_setup_msi_irqs() (for a different reason) and
> I am no longer sure this patch does anything:
> 
> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> {
>         int irq, ret, i;
>         struct msi_desc *msidesc;
>         int *v;
> 
>         if (type == PCI_CAP_ID_MSI && nvec > 1)
>                 return 1;
> ....
> 
> Same thing for xen_hvm_setup_msi_irqs().

As said in the commit message this is only for Dom0, so the function
modified is xen_initdom_setup_msi_irqs (were this check is removed).

Roger.

Re: [PATCH v2] xen: add support for MSI message groups

[Roger Pau Monné]

On 28/02/14 18:20, Boris Ostrovsky wrote:
> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>> Add support for MSI message groups for Xen Dom0 using the
>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>
>>> In order to keep track of which pirq is the first one in the group all
>>> pirqs in the MSI group except for the first one have the newly
>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>> first pirq in the group.
>>
>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>
>>
> 
> 
> I was just looking at xen_setup_msi_irqs() (for a different reason) and
> I am no longer sure this patch does anything:
> 
> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> {
>         int irq, ret, i;
>         struct msi_desc *msidesc;
>         int *v;
> 
>         if (type == PCI_CAP_ID_MSI && nvec > 1)
>                 return 1;
> ....
> 
> Same thing for xen_hvm_setup_msi_irqs().

As said in the commit message this is only for Dom0, so the function
modified is xen_initdom_setup_msi_irqs (were this check is removed).

Roger.

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
> On 28/02/14 18:20, Boris Ostrovsky wrote:
>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>> Add support for MSI message groups for Xen Dom0 using the
>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>
>>>> In order to keep track of which pirq is the first one in the group all
>>>> pirqs in the MSI group except for the first one have the newly
>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>> first pirq in the group.
>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>
>>>
>>
>> I was just looking at xen_setup_msi_irqs() (for a different reason) and
>> I am no longer sure this patch does anything:
>>
>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>> {
>>          int irq, ret, i;
>>          struct msi_desc *msidesc;
>>          int *v;
>>
>>          if (type == PCI_CAP_ID_MSI && nvec > 1)
>>                  return 1;
>> ....
>>
>> Same thing for xen_hvm_setup_msi_irqs().
> As said in the commit message this is only for Dom0, so the function
> modified is xen_initdom_setup_msi_irqs (were this check is removed).

Then what is the reason for these changes:

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702..905956f 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  	i = 0;
  	list_for_each_entry(msidesc, &dev->msi_list, list) {
  		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
  					       (type == PCI_CAP_ID_MSIX) ?
  					       "pcifront-msi-x" :
  					       "pcifront-msi",
@@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  				"xen: msi already bound to pirq=%d\n", pirq);
  		}
  		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
  					       (type == PCI_CAP_ID_MSIX) ?
  					       "msi-x" : "msi",
  					       DOMID_SELF);

Should you simply pass 1?

-boris

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
> On 28/02/14 18:20, Boris Ostrovsky wrote:
>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>> Add support for MSI message groups for Xen Dom0 using the
>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>
>>>> In order to keep track of which pirq is the first one in the group all
>>>> pirqs in the MSI group except for the first one have the newly
>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>> first pirq in the group.
>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>
>>>
>>
>> I was just looking at xen_setup_msi_irqs() (for a different reason) and
>> I am no longer sure this patch does anything:
>>
>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>> {
>>          int irq, ret, i;
>>          struct msi_desc *msidesc;
>>          int *v;
>>
>>          if (type == PCI_CAP_ID_MSI && nvec > 1)
>>                  return 1;
>> ....
>>
>> Same thing for xen_hvm_setup_msi_irqs().
> As said in the commit message this is only for Dom0, so the function
> modified is xen_initdom_setup_msi_irqs (were this check is removed).

Then what is the reason for these changes:

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702..905956f 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  	i = 0;
  	list_for_each_entry(msidesc, &dev->msi_list, list) {
  		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
  					       (type == PCI_CAP_ID_MSIX) ?
  					       "pcifront-msi-x" :
  					       "pcifront-msi",
@@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  				"xen: msi already bound to pirq=%d\n", pirq);
  		}
  		irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+					       (type == PCI_CAP_ID_MSI) ? nvec : 1,
  					       (type == PCI_CAP_ID_MSIX) ?
  					       "msi-x" : "msi",
  					       DOMID_SELF);

Should you simply pass 1?

-boris


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Re: [PATCH v2] xen: add support for MSI message groups

[Roger Pau Monné]

On 28/02/14 19:00, Boris Ostrovsky wrote:
> On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
>> On 28/02/14 18:20, Boris Ostrovsky wrote:
>>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>>> Add support for MSI message groups for Xen Dom0 using the
>>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>>
>>>>> In order to keep track of which pirq is the first one in the group all
>>>>> pirqs in the MSI group except for the first one have the newly
>>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>>> first pirq in the group.
>>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>
>>>>
>>>
>>> I was just looking at xen_setup_msi_irqs() (for a different reason) and
>>> I am no longer sure this patch does anything:
>>>
>>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>>> {
>>>          int irq, ret, i;
>>>          struct msi_desc *msidesc;
>>>          int *v;
>>>
>>>          if (type == PCI_CAP_ID_MSI && nvec > 1)
>>>                  return 1;
>>> ....
>>>
>>> Same thing for xen_hvm_setup_msi_irqs().
>> As said in the commit message this is only for Dom0, so the function
>> modified is xen_initdom_setup_msi_irqs (were this check is removed).
> 
> Then what is the reason for these changes:
> 
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 103e702..905956f 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
> int nvec, int type)
>      i = 0;
>      list_for_each_entry(msidesc, &dev->msi_list, list) {
>          irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>                             (type == PCI_CAP_ID_MSIX) ?
>                             "pcifront-msi-x" :
>                             "pcifront-msi",
> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
> *dev, int nvec, int type)
>                  "xen: msi already bound to pirq=%d\n", pirq);
>          }
>          irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>                             (type == PCI_CAP_ID_MSIX) ?
>                             "msi-x" : "msi",
>                             DOMID_SELF);
> 
> Should you simply pass 1?

Yes, but then if we implement MSI message groups for those cases we will
need to modify this line again, this way it's already correctly setup.
If you think it's best to hardcode it to 1, I can change it (I was also
in doubt about which way was better when modifying those lines).

Roger.

Re: [PATCH v2] xen: add support for MSI message groups

[Roger Pau Monné]

On 28/02/14 19:00, Boris Ostrovsky wrote:
> On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
>> On 28/02/14 18:20, Boris Ostrovsky wrote:
>>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>>> Add support for MSI message groups for Xen Dom0 using the
>>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>>
>>>>> In order to keep track of which pirq is the first one in the group all
>>>>> pirqs in the MSI group except for the first one have the newly
>>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>>> first pirq in the group.
>>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>
>>>>
>>>
>>> I was just looking at xen_setup_msi_irqs() (for a different reason) and
>>> I am no longer sure this patch does anything:
>>>
>>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>>> {
>>>          int irq, ret, i;
>>>          struct msi_desc *msidesc;
>>>          int *v;
>>>
>>>          if (type == PCI_CAP_ID_MSI && nvec > 1)
>>>                  return 1;
>>> ....
>>>
>>> Same thing for xen_hvm_setup_msi_irqs().
>> As said in the commit message this is only for Dom0, so the function
>> modified is xen_initdom_setup_msi_irqs (were this check is removed).
> 
> Then what is the reason for these changes:
> 
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 103e702..905956f 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
> int nvec, int type)
>      i = 0;
>      list_for_each_entry(msidesc, &dev->msi_list, list) {
>          irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>                             (type == PCI_CAP_ID_MSIX) ?
>                             "pcifront-msi-x" :
>                             "pcifront-msi",
> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
> *dev, int nvec, int type)
>                  "xen: msi already bound to pirq=%d\n", pirq);
>          }
>          irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>                             (type == PCI_CAP_ID_MSIX) ?
>                             "msi-x" : "msi",
>                             DOMID_SELF);
> 
> Should you simply pass 1?

Yes, but then if we implement MSI message groups for those cases we will
need to modify this line again, this way it's already correctly setup.
If you think it's best to hardcode it to 1, I can change it (I was also
in doubt about which way was better when modifying those lines).

Roger.

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Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/28/2014 01:10 PM, Roger Pau Monné wrote:
> On 28/02/14 19:00, Boris Ostrovsky wrote:
>> On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
>>> On 28/02/14 18:20, Boris Ostrovsky wrote:
>>>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>>>> Add support for MSI message groups for Xen Dom0 using the
>>>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>>>
>>>>>> In order to keep track of which pirq is the first one in the group all
>>>>>> pirqs in the MSI group except for the first one have the newly
>>>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>>>> first pirq in the group.
>>>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>>
>>>>>
>>>> I was just looking at xen_setup_msi_irqs() (for a different reason) and
>>>> I am no longer sure this patch does anything:
>>>>
>>>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>>>> {
>>>>           int irq, ret, i;
>>>>           struct msi_desc *msidesc;
>>>>           int *v;
>>>>
>>>>           if (type == PCI_CAP_ID_MSI && nvec > 1)
>>>>                   return 1;
>>>> ....
>>>>
>>>> Same thing for xen_hvm_setup_msi_irqs().
>>> As said in the commit message this is only for Dom0, so the function
>>> modified is xen_initdom_setup_msi_irqs (were this check is removed).
>> Then what is the reason for these changes:
>>
>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>> index 103e702..905956f 100644
>> --- a/arch/x86/pci/xen.c
>> +++ b/arch/x86/pci/xen.c
>> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
>> int nvec, int type)
>>       i = 0;
>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "pcifront-msi-x" :
>>                              "pcifront-msi",
>> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
>> *dev, int nvec, int type)
>>                   "xen: msi already bound to pirq=%d\n", pirq);
>>           }
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "msi-x" : "msi",
>>                              DOMID_SELF);
>>
>> Should you simply pass 1?
> Yes, but then if we implement MSI message groups for those cases we will
> need to modify this line again, this way it's already correctly setup.
> If you think it's best to hardcode it to 1, I can change it (I was also
> in doubt about which way was better when modifying those lines).


I think passing 1 explicitly this would be better. If we extend support 
for non-dom0 we would have to modify these routines anyway so making 
changes in both places simultaneously would make the commit more clear 
(IMO).

-boris

Re: [PATCH v2] xen: add support for MSI message groups

[Boris Ostrovsky]

On 02/28/2014 01:10 PM, Roger Pau Monné wrote:
> On 28/02/14 19:00, Boris Ostrovsky wrote:
>> On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
>>> On 28/02/14 18:20, Boris Ostrovsky wrote:
>>>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>>>> Add support for MSI message groups for Xen Dom0 using the
>>>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>>>
>>>>>> In order to keep track of which pirq is the first one in the group all
>>>>>> pirqs in the MSI group except for the first one have the newly
>>>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>>>> first pirq in the group.
>>>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>>
>>>>>
>>>> I was just looking at xen_setup_msi_irqs() (for a different reason) and
>>>> I am no longer sure this patch does anything:
>>>>
>>>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>>>> {
>>>>           int irq, ret, i;
>>>>           struct msi_desc *msidesc;
>>>>           int *v;
>>>>
>>>>           if (type == PCI_CAP_ID_MSI && nvec > 1)
>>>>                   return 1;
>>>> ....
>>>>
>>>> Same thing for xen_hvm_setup_msi_irqs().
>>> As said in the commit message this is only for Dom0, so the function
>>> modified is xen_initdom_setup_msi_irqs (were this check is removed).
>> Then what is the reason for these changes:
>>
>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>> index 103e702..905956f 100644
>> --- a/arch/x86/pci/xen.c
>> +++ b/arch/x86/pci/xen.c
>> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
>> int nvec, int type)
>>       i = 0;
>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "pcifront-msi-x" :
>>                              "pcifront-msi",
>> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
>> *dev, int nvec, int type)
>>                   "xen: msi already bound to pirq=%d\n", pirq);
>>           }
>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>                              (type == PCI_CAP_ID_MSIX) ?
>>                              "msi-x" : "msi",
>>                              DOMID_SELF);
>>
>> Should you simply pass 1?
> Yes, but then if we implement MSI message groups for those cases we will
> need to modify this line again, this way it's already correctly setup.
> If you think it's best to hardcode it to 1, I can change it (I was also
> in doubt about which way was better when modifying those lines).


I think passing 1 explicitly this would be better. If we extend support 
for non-dom0 we would have to modify these routines anyway so making 
changes in both places simultaneously would make the commit more clear 
(IMO).

-boris


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Re: [PATCH v2] xen: add support for MSI message groups

[David Vrabel]

On 28/02/14 18:36, Boris Ostrovsky wrote:
> On 02/28/2014 01:10 PM, Roger Pau Monné wrote:
>> On 28/02/14 19:00, Boris Ostrovsky wrote:
>>> On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
>>>> On 28/02/14 18:20, Boris Ostrovsky wrote:
>>>>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>>>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>>>>> Add support for MSI message groups for Xen Dom0 using the
>>>>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>>>>
>>>>>>> In order to keep track of which pirq is the first one in the
>>>>>>> group all
>>>>>>> pirqs in the MSI group except for the first one have the newly
>>>>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>>>>> first pirq in the group.
>>>>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>>>
>>>>>>
>>>>> I was just looking at xen_setup_msi_irqs() (for a different reason)
>>>>> and
>>>>> I am no longer sure this patch does anything:
>>>>>
>>>>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>>>>> {
>>>>>           int irq, ret, i;
>>>>>           struct msi_desc *msidesc;
>>>>>           int *v;
>>>>>
>>>>>           if (type == PCI_CAP_ID_MSI && nvec > 1)
>>>>>                   return 1;
>>>>> ....
>>>>>
>>>>> Same thing for xen_hvm_setup_msi_irqs().
>>>> As said in the commit message this is only for Dom0, so the function
>>>> modified is xen_initdom_setup_msi_irqs (were this check is removed).
>>> Then what is the reason for these changes:
>>>
>>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>>> index 103e702..905956f 100644
>>> --- a/arch/x86/pci/xen.c
>>> +++ b/arch/x86/pci/xen.c
>>> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
>>> int nvec, int type)
>>>       i = 0;
>>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
>>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>>                              (type == PCI_CAP_ID_MSIX) ?
>>>                              "pcifront-msi-x" :
>>>                              "pcifront-msi",
>>> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
>>> *dev, int nvec, int type)
>>>                   "xen: msi already bound to pirq=%d\n", pirq);
>>>           }
>>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
>>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>>                              (type == PCI_CAP_ID_MSIX) ?
>>>                              "msi-x" : "msi",
>>>                              DOMID_SELF);
>>>
>>> Should you simply pass 1?
>> Yes, but then if we implement MSI message groups for those cases we will
>> need to modify this line again, this way it's already correctly setup.
>> If you think it's best to hardcode it to 1, I can change it (I was also
>> in doubt about which way was better when modifying those lines).
> 
> 
> I think passing 1 explicitly this would be better. If we extend support
> for non-dom0 we would have to modify these routines anyway so making
> changes in both places simultaneously would make the commit more clear
> (IMO).

If we know now that this will need to be changed, it's better to do it
now than forget about it later.

Applied to devel/for-linus-3.15, thanks.

David

Re: [PATCH v2] xen: add support for MSI message groups

[David Vrabel]

On 28/02/14 18:36, Boris Ostrovsky wrote:
> On 02/28/2014 01:10 PM, Roger Pau Monné wrote:
>> On 28/02/14 19:00, Boris Ostrovsky wrote:
>>> On 02/28/2014 12:46 PM, Roger Pau Monné wrote:
>>>> On 28/02/14 18:20, Boris Ostrovsky wrote:
>>>>> On 02/27/2014 01:45 PM, Boris Ostrovsky wrote:
>>>>>> On 02/27/2014 01:15 PM, Roger Pau Monne wrote:
>>>>>>> Add support for MSI message groups for Xen Dom0 using the
>>>>>>> MAP_PIRQ_TYPE_MULTI_MSI pirq map type.
>>>>>>>
>>>>>>> In order to keep track of which pirq is the first one in the
>>>>>>> group all
>>>>>>> pirqs in the MSI group except for the first one have the newly
>>>>>>> introduced PIRQ_MSI_GROUP flag set. This prevents calling
>>>>>>> PHYSDEVOP_unmap_pirq on them, since the unmap must be done with the
>>>>>>> first pirq in the group.
>>>>>> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>>>>>
>>>>>>
>>>>> I was just looking at xen_setup_msi_irqs() (for a different reason)
>>>>> and
>>>>> I am no longer sure this patch does anything:
>>>>>
>>>>> static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>>>>> {
>>>>>           int irq, ret, i;
>>>>>           struct msi_desc *msidesc;
>>>>>           int *v;
>>>>>
>>>>>           if (type == PCI_CAP_ID_MSI && nvec > 1)
>>>>>                   return 1;
>>>>> ....
>>>>>
>>>>> Same thing for xen_hvm_setup_msi_irqs().
>>>> As said in the commit message this is only for Dom0, so the function
>>>> modified is xen_initdom_setup_msi_irqs (were this check is removed).
>>> Then what is the reason for these changes:
>>>
>>> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
>>> index 103e702..905956f 100644
>>> --- a/arch/x86/pci/xen.c
>>> +++ b/arch/x86/pci/xen.c
>>> @@ -178,6 +178,7 @@ static int xen_setup_msi_irqs(struct pci_dev *dev,
>>> int nvec, int type)
>>>       i = 0;
>>>       list_for_each_entry(msidesc, &dev->msi_list, list) {
>>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
>>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>>                              (type == PCI_CAP_ID_MSIX) ?
>>>                              "pcifront-msi-x" :
>>>                              "pcifront-msi",
>>> @@ -245,6 +246,7 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev
>>> *dev, int nvec, int type)
>>>                   "xen: msi already bound to pirq=%d\n", pirq);
>>>           }
>>>           irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
>>> +                           (type == PCI_CAP_ID_MSI) ? nvec : 1,
>>>                              (type == PCI_CAP_ID_MSIX) ?
>>>                              "msi-x" : "msi",
>>>                              DOMID_SELF);
>>>
>>> Should you simply pass 1?
>> Yes, but then if we implement MSI message groups for those cases we will
>> need to modify this line again, this way it's already correctly setup.
>> If you think it's best to hardcode it to 1, I can change it (I was also
>> in doubt about which way was better when modifying those lines).
> 
> 
> I think passing 1 explicitly this would be better. If we extend support
> for non-dom0 we would have to modify these routines anyway so making
> changes in both places simultaneously would make the commit more clear
> (IMO).

If we know now that this will need to be changed, it's better to do it
now than forget about it later.

Applied to devel/for-linus-3.15, thanks.

David

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