diff --git a/drivers/xen/xen-pciback/pciback_ops.c b/drivers/xen/xen-pciback/pciback_ops.c
index 4ee5fc080483d595147620fcb6c2306129f62130..73dafdc494aa8322e037f1d4a9ad4ec5530c5743 100644
--- a/drivers/xen/xen-pciback/pciback_ops.c
+++ b/drivers/xen/xen-pciback/pciback_ops.c
@@ -212,6 +212,7 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
 	struct xen_pcibk_dev_data *dev_data;
 	int i, result;
 	struct msix_entry *entries;
+	u16 cmd;
 
 	if (unlikely(verbose_request))
 		printk(KERN_DEBUG DRV_NAME ": %s: enable MSI-X\n",
@@ -223,7 +224,12 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
 	if (dev->msix_enabled)
 		return -EALREADY;
 
-	if (dev->msi_enabled)
+	/*
+	 * PCI_COMMAND_MEMORY must be enabled, otherwise we may not be able
+	 * to access the BARs where the MSI-X entries reside.
+	 */
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	if (dev->msi_enabled || !(cmd & PCI_COMMAND_MEMORY))
 		return -ENXIO;
 
 	entries = kmalloc(op->value * sizeof(*entries), GFP_KERNEL);