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>

1 files changed, 20 insertions, 9 deletions

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 103e702ec5a7..905956f16465 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;
         }