xen-pciback: rate limit error messages from xen_pcibk_enable_msi{,x}()

... as being guest triggerable (e.g. by invoking
XEN_PCI_OP_enable_msi{,x} on a device not being MSI/MSI-X capable).

This is CVE-2013-0231 / XSA-43.

Also make the two messages uniform in both their wording and severity.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c
index 97f5d26..37c1f82 100644 (file)
--- a/drivers/xen/xen-pciback/pciback_ops.c
+++ b/drivers/xen/xen-pciback/pciback_ops.c
@@ -135,7 +135,6 @@ int xen_pcibk_enable_msi(struct xen_pcibk_device *pdev,
                         struct pci_dev *dev, struct xen_pci_op *op)
 {
        struct xen_pcibk_dev_data *dev_data;
-       int otherend = pdev->xdev->otherend_id;
        int status;
 
        if (unlikely(verbose_request))
@@ -144,8 +143,9 @@ int xen_pcibk_enable_msi(struct xen_pcibk_device *pdev,
        status = pci_enable_msi(dev);
 
        if (status) {
-               printk(KERN_ERR "error enable msi for guest %x status %x\n",
-                       otherend, status);
+               pr_warn_ratelimited(DRV_NAME ": %s: error enabling MSI for guest %u: err %d\n",
+                                   pci_name(dev), pdev->xdev->otherend_id,
+                                   status);
                op->value = 0;
                return XEN_PCI_ERR_op_failed;
        }
@@ -223,10 +223,10 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
                                                pci_name(dev), i,
                                                op->msix_entries[i].vector);
                }
-       } else {
-               printk(KERN_WARNING DRV_NAME ": %s: failed to enable MSI-X: err %d!\n",
-                       pci_name(dev), result);
-       }
+       } else
+               pr_warn_ratelimited(DRV_NAME ": %s: error enabling MSI-X for guest %u: err %d!\n",
+                                   pci_name(dev), pdev->xdev->otherend_id,
+                                   result);
        kfree(entries);
 
        op->value = result;