xen: add support for MSI message groups

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>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>

2 files changed, 33 insertions, 15 deletions

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 9875d6ec1063..793053065629 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;
@@ -738,22 +746,25 @@ 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;
@@ -761,7 +772,8 @@ 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;
 }
@@ -780,7 +792,12 @@ 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 677f41a0fff9..50c2050a1e32 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);