xen/pci: support multi-segment systems

Now that the hypercall interface changes are in -unstable, make the
kernel side code not ignore the segment (aka domain) number anymore
(which results in pretty odd behavior on such systems). Rather, if
only the old interfaces are available, don't call them for devices on
non-zero segments at all.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
[v1: Edited git description]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 19 insertions, 3 deletions

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index f567965c0620..265fa8814ccd 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -185,6 +185,8 @@ static void xen_teardown_msi_irq(unsigned int irq)
 }
 
 #ifdef CONFIG_XEN_DOM0
+static bool __read_mostly pci_seg_supported = true;
+
 static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 {
         int ret = 0;
@@ -202,10 +204,11 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 
                 memset(&map_irq, 0, sizeof(map_irq));
                 map_irq.domid = domid;
-                map_irq.type = MAP_PIRQ_TYPE_MSI;
+                map_irq.type = MAP_PIRQ_TYPE_MSI_SEG;
                 map_irq.index = -1;
                 map_irq.pirq = -1;
-                map_irq.bus = dev->bus->number;
+                map_irq.bus = dev->bus->number |
+                              (pci_domain_nr(dev->bus) << 16);
                 map_irq.devfn = dev->devfn;
 
                 if (type == PCI_CAP_ID_MSIX) {
@@ -222,7 +225,20 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
                         map_irq.entry_nr = msidesc->msi_attrib.entry_nr;
                 }
 
-                ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
+                ret = -EINVAL;
+                if (pci_seg_supported)
+                        ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
+                                                    &map_irq);
+                if (ret == -EINVAL && !pci_domain_nr(dev->bus)) {
+                        map_irq.type = MAP_PIRQ_TYPE_MSI;
+                        map_irq.index = -1;
+                        map_irq.pirq = -1;
+                        map_irq.bus = dev->bus->number;
+                        ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
+                                                    &map_irq);
+                        if (ret != -EINVAL)
+                                pci_seg_supported = false;
+                }
                 if (ret) {
                         dev_warn(&dev->dev, "xen map irq failed %d for %d domain\n",
                                  ret, domid);