xen/pcifront: Report the errors better.

The messages should be different depending on the type of error.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

arch/x86/include/asm/xen/pci.h

@@ -57,7 +57,7 @@ static inline int xen_pci_frontend_enable_msi(struct pci_dev *dev,
 {
 	if (xen_pci_frontend && xen_pci_frontend->enable_msi)
 		return xen_pci_frontend->enable_msi(dev, vectors);
-	return -ENODEV;
+	return -ENOSYS;
 }
 static inline void xen_pci_frontend_disable_msi(struct pci_dev *dev)
 {
@@ -69,7 +69,7 @@ static inline int xen_pci_frontend_enable_msix(struct pci_dev *dev,
 {
 	if (xen_pci_frontend && xen_pci_frontend->enable_msix)
 		return xen_pci_frontend->enable_msix(dev, vectors, nvec);
-	return -ENODEV;
+	return -ENOSYS;
 }
 static inline void xen_pci_frontend_disable_msix(struct pci_dev *dev)
 {

arch/x86/pci/xen.c

@@ -196,7 +196,10 @@ static int xen_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 	return 0;
 
 error:
-	dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
+	if (ret == -ENOSYS)
+		dev_err(&dev->dev, "Xen PCI frontend has not registered MSI/MSI-X support!\n");
+	else if (ret)
+		dev_err(&dev->dev, "Xen PCI frontend error: %d!\n", ret);
 free:
 	kfree(v);
 	return ret;