s390x/pci: merge msix init functions

Currently there're two functions, s390_pci_setup_msix() and
s390_pci_msix_init(), for msix initialization, and being called once
for each zpci device plugging. Let's integrate them.

Moreover msix is mandatory in s390 architecture. So we ensure the pci
device being plugged supports msix. For vfio (which is the only tested
setup so far), nothing changes.
Signed-off-by: NYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/s390-pci-bus.c

@@ -582,8 +582,9 @@ static int s390_pcihost_init(SysBusDevice *dev)
     return 0;
 }
 
-static int s390_pci_setup_msix(S390PCIBusDevice *pbdev)
+static int s390_pci_msix_init(S390PCIBusDevice *pbdev)
 {
+    char *name;
     uint8_t pos;
     uint16_t ctrl;
     uint32_t table, pba;
@@ -591,7 +592,7 @@ static int s390_pci_setup_msix(S390PCIBusDevice *pbdev)
     pos = pci_find_capability(pbdev->pdev, PCI_CAP_ID_MSIX);
     if (!pos) {
         pbdev->msix.available = false;
-        return 0;
+        return -1;
     }
 
     ctrl = pci_host_config_read_common(pbdev->pdev, pos + PCI_MSIX_FLAGS,
@@ -607,21 +608,15 @@ static int s390_pci_setup_msix(S390PCIBusDevice *pbdev)
     pbdev->msix.pba_offset = pba & ~PCI_MSIX_FLAGS_BIRMASK;
     pbdev->msix.entries = (ctrl & PCI_MSIX_FLAGS_QSIZE) + 1;
     pbdev->msix.available = true;
-    return 0;
-}
-
-static void s390_pci_msix_init(S390PCIBusDevice *pbdev)
-{
-    char *name;
 
     name = g_strdup_printf("msix-s390-%04x", pbdev->uid);
-
     memory_region_init_io(&pbdev->msix_notify_mr, OBJECT(pbdev),
                           &s390_msi_ctrl_ops, pbdev, name, PAGE_SIZE);
     memory_region_add_subregion(&pbdev->iommu->mr, ZPCI_MSI_ADDR,
                                 &pbdev->msix_notify_mr);
-
     g_free(name);
+
+    return 0;
 }
 
 static void s390_pci_msix_free(S390PCIBusDevice *pbdev)
@@ -724,8 +719,11 @@ static void s390_pcihost_hot_plug(HotplugHandler *hotplug_dev,
         pbdev->iommu->pbdev = pbdev;
         pbdev->state = ZPCI_FS_STANDBY;
 
-        s390_pci_msix_init(pbdev);
-        s390_pci_setup_msix(pbdev);
+        if (s390_pci_msix_init(pbdev)) {
+            error_setg(errp, "MSI-X support is mandatory "
+                       "in the S390 architecture");
+            return;
+        }
 
         if (dev->hotplugged) {
             s390_pci_generate_plug_event(HP_EVENT_RESERVED_TO_STANDBY,