[Xen-devel] [PATCH] linux-2.6.18/MSI-X: Avoid unconditional BUG() in DomU

["Jan Beulich" <JBeulich@xxxxxxxx>]

msi_remove_pci_irq_vectors() unconditionally (i.e. even in a DomU)
calling msi_unmap_pirq() is guaranteed to BUG() in msi_get_dev_owner().
Adjust the function to call evtchn_map_pirq() instead in a DomU (just
like pci_disable_msix() is doing).

While looking into this I also realized that the
CONFIG_XEN_PCIDEV_FRONTEND conditionals are misplaced - since on x86-64
it is possible to build with this disabled, execution would flow into
Dom0 code even on a DomU in this case. Hence adjust their placement at
once.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/drivers/pci/msi-xen.c
+++ b/drivers/pci/msi-xen.c
@@ -547,9 +547,8 @@ int pci_enable_msi(struct pci_dev* dev
        if (status < 0)
                return status;
 
+       if (!is_initial_xendomain()) {
 #ifdef CONFIG_XEN_PCIDEV_FRONTEND
-       if (!is_initial_xendomain())
-       {
                int ret;
 
                temp = dev->irq;
@@ -563,8 +562,10 @@ int pci_enable_msi(struct pci_dev* dev
                msi_dev_entry->default_irq = temp;
 
                return ret;
-       }
+#else
+               return -EOPNOTSUPP;
 #endif
+       }
 
        temp = dev->irq;
 
@@ -592,8 +593,8 @@ void pci_disable_msi(struct pci_dev* dev
        if (!dev)
                return;
 
-#ifdef CONFIG_XEN_PCIDEV_FRONTEND
        if (!is_initial_xendomain()) {
+#ifdef CONFIG_XEN_PCIDEV_FRONTEND
                if (!(dev->msi_enabled)) {
                        printk(KERN_INFO "PCI: %s: Device did not enabled 
MSI.\n",
                               pci_name(dev));
@@ -603,9 +604,9 @@ void pci_disable_msi(struct pci_dev* dev
                pci_frontend_disable_msi(dev);
                dev->irq = msi_dev_entry->default_irq;
                dev->msi_enabled = 0;
+#endif
                return;
        }
-#endif
 
        pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
        if (!pos)
@@ -663,8 +664,8 @@ void pci_disable_msix(struct pci_dev *de
                if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
                        return -EINVAL;
 
-#ifdef CONFIG_XEN_PCIDEV_FRONTEND
        if (!is_initial_xendomain()) {
+#ifdef CONFIG_XEN_PCIDEV_FRONTEND
                struct msi_pirq_entry *pirq_entry;
                int ret, irq;
 
@@ -696,9 +697,11 @@ int pci_enable_msix(struct pci_dev* dev,
                        attach_pirq_entry(irq, entries[i].entry, msi_dev_entry);
                        entries[i].vector = irq;
                }
-        return 0;
-       }
+               return 0;
+#else
+               return -EOPNOTSUPP;
 #endif
+       }
 
        status = msi_init();
        if (status < 0)
@@ -741,8 +744,8 @@ void pci_disable_msix(struct pci_dev *de
                return;
        }
 
-#ifdef CONFIG_XEN_PCIDEV_FRONTEND
        if (!is_initial_xendomain()) {
+#ifdef CONFIG_XEN_PCIDEV_FRONTEND
                struct msi_dev_list *msi_dev_entry;
                struct msi_pirq_entry *pirq_entry, *tmp;

@@ -758,9 +761,9 @@ void pci_msix_shutdown(struct pci_dev *d

                dev->irq = msi_dev_entry->default_irq;
                dev->msix_enabled = 0;
+#endif
                return;
        }
-#endif
 
        pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
        if (!pos)
@@ -800,7 +791,10 @@ void msi_remove_pci_irq_vectors(struct p
        if (!list_empty(&msi_dev_entry->pirq_list_head))
                list_for_each_entry_safe(pirq_entry, tmp,
                                         &msi_dev_entry->pirq_list_head, list) {
-                       msi_unmap_pirq(dev, pirq_entry->pirq);
+                       if (is_initial_xendomain())
+                               msi_unmap_pirq(dev, pirq_entry->pirq);
+                       else
+                               evtchn_map_pirq(pirq_entry->pirq, 0);
                        list_del(&pirq_entry->list);
                        kfree(pirq_entry);
                }




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel