Xen bug fixes for 4.5-rc5

- Two scsiback fixes (resource leak and spurious warning).
 - Fix DMA mapping of compound pages on arm/arm64.
 - Fix some pciback regressions in MSI-X handling.
 - Fix a pcifront crash due to some uninitialize state.
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Merge tag 'for-linus-4.5-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen bug fixes from David Vrabel:

 - Two scsiback fixes (resource leak and spurious warning).

 - Fix DMA mapping of compound pages on arm/arm64.

 - Fix some pciback regressions in MSI-X handling.

 - Fix a pcifront crash due to some uninitialize state.

* tag 'for-linus-4.5-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pcifront: Fix mysterious crashes when NUMA locality information was extracted.
  xen/pcifront: Report the errors better.
  xen/pciback: Save the number of MSI-X entries to be copied later.
  xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY
  xen: fix potential integer overflow in queue_reply
  xen/arm: correctly handle DMA mapping of compound pages
  xen/scsiback: avoid warnings when adding multiple LUNs to a domain
  xen/scsiback: correct frontend counting

arch/arm/include/asm/xen/page-coherent.h

@@ -35,14 +35,21 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
 	     dma_addr_t dev_addr, unsigned long offset, size_t size,
 	     enum dma_data_direction dir, struct dma_attrs *attrs)
 {
-	bool local = XEN_PFN_DOWN(dev_addr) == page_to_xen_pfn(page);
+	unsigned long page_pfn = page_to_xen_pfn(page);
+	unsigned long dev_pfn = XEN_PFN_DOWN(dev_addr);
+	unsigned long compound_pages =
+		(1<<compound_order(page)) * XEN_PFN_PER_PAGE;
+	bool local = (page_pfn <= dev_pfn) &&
+		(dev_pfn - page_pfn < compound_pages);
+
 	/*
-	 * Dom0 is mapped 1:1, while the Linux page can be spanned accross
-	 * multiple Xen page, it's not possible to have a mix of local and
-	 * foreign Xen page. So if the first xen_pfn == mfn the page is local
-	 * otherwise it's a foreign page grant-mapped in dom0. If the page is
-	 * local we can safely call the native dma_ops function, otherwise we
-	 * call the xen specific function.
+	 * Dom0 is mapped 1:1, while the Linux page can span across
+	 * multiple Xen pages, it's not possible for it to contain a
+	 * mix of local and foreign Xen pages. So if the first xen_pfn
+	 * == mfn the page is local otherwise it's a foreign page
+	 * grant-mapped in dom0. If the page is local we can safely
+	 * call the native dma_ops function, otherwise we call the xen
+	 * specific function.
 	 */
 	if (local)
 		__generic_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);

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:
+	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;

drivers/pci/xen-pcifront.c

@@ -53,7 +53,7 @@ struct pcifront_device {
 };
 
 struct pcifront_sd {
-	int domain;
+	struct pci_sysdata sd;
 	struct pcifront_device *pdev;
 };
 
@@ -67,7 +67,9 @@ static inline void pcifront_init_sd(struct pcifront_sd *sd,
 				    unsigned int domain, unsigned int bus,
 				    struct pcifront_device *pdev)
 {
-	sd->domain = domain;
+	/* Because we do not expose that information via XenBus. */
+	sd->sd.node = first_online_node;
+	sd->sd.domain = domain;
 	sd->pdev = pdev;
 }
 
@@ -468,8 +470,8 @@ static int pcifront_scan_root(struct pcifront_device *pdev,
 	dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
 		 domain, bus);
 
-	bus_entry = kmalloc(sizeof(*bus_entry), GFP_KERNEL);
-	sd = kmalloc(sizeof(*sd), GFP_KERNEL);
+	bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL);
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
 	if (!bus_entry || !sd) {
 		err = -ENOMEM;
 		goto err_out;

drivers/xen/xen-pciback/pciback_ops.c

@@ -227,8 +227,9 @@ int xen_pcibk_enable_msix(struct xen_pcibk_device *pdev,
 	/*
 	 * PCI_COMMAND_MEMORY must be enabled, otherwise we may not be able
 	 * to access the BARs where the MSI-X entries reside.
+	 * But VF devices are unique in which the PF needs to be checked.
 	 */
-	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	pci_read_config_word(pci_physfn(dev), PCI_COMMAND, &cmd);
 	if (dev->msi_enabled || !(cmd & PCI_COMMAND_MEMORY))
 		return -ENXIO;
 
@@ -332,6 +333,9 @@ void xen_pcibk_do_op(struct work_struct *data)
 	struct xen_pcibk_dev_data *dev_data = NULL;
 	struct xen_pci_op *op = &pdev->op;
 	int test_intx = 0;
+#ifdef CONFIG_PCI_MSI
+	unsigned int nr = 0;
+#endif
 
 	*op = pdev->sh_info->op;
 	barrier();
@@ -360,6 +364,7 @@ void xen_pcibk_do_op(struct work_struct *data)
 			op->err = xen_pcibk_disable_msi(pdev, dev, op);
 			break;
 		case XEN_PCI_OP_enable_msix:
+			nr = op->value;
 			op->err = xen_pcibk_enable_msix(pdev, dev, op);
 			break;
 		case XEN_PCI_OP_disable_msix:
@@ -382,7 +387,7 @@ void xen_pcibk_do_op(struct work_struct *data)
 	if (op->cmd == XEN_PCI_OP_enable_msix && op->err == 0) {
 		unsigned int i;
 
-		for (i = 0; i < op->value; i++)
+		for (i = 0; i < nr; i++)
 			pdev->sh_info->op.msix_entries[i].vector =
 				op->msix_entries[i].vector;
 	}

drivers/xen/xen-scsiback.c

@@ -848,6 +848,24 @@ static int scsiback_map(struct vscsibk_info *info)
 	return scsiback_init_sring(info, ring_ref, evtchn);
 }
 
+/*
+  Check for a translation entry being present
+*/
+static struct v2p_entry *scsiback_chk_translation_entry(
+	struct vscsibk_info *info, struct ids_tuple *v)
+{
+	struct list_head *head = &(info->v2p_entry_lists);
+	struct v2p_entry *entry;
+
+	list_for_each_entry(entry, head, l)
+		if ((entry->v.chn == v->chn) &&
+		    (entry->v.tgt == v->tgt) &&
+		    (entry->v.lun == v->lun))
+			return entry;
+
+	return NULL;
+}
+
 /*
   Add a new translation entry
 */
@@ -855,9 +873,7 @@ static int scsiback_add_translation_entry(struct vscsibk_info *info,
 					  char *phy, struct ids_tuple *v)
 {
 	int err = 0;
-	struct v2p_entry *entry;
 	struct v2p_entry *new;
-	struct list_head *head = &(info->v2p_entry_lists);
 	unsigned long flags;
 	char *lunp;
 	unsigned long long unpacked_lun;
@@ -917,34 +933,29 @@ static int scsiback_add_translation_entry(struct vscsibk_info *info,
 	spin_lock_irqsave(&info->v2p_lock, flags);
 
 	/* Check double assignment to identical virtual ID */
-	list_for_each_entry(entry, head, l) {
-		if ((entry->v.chn == v->chn) &&
-		    (entry->v.tgt == v->tgt) &&
-		    (entry->v.lun == v->lun)) {
+	if (scsiback_chk_translation_entry(info, v)) {
 		pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 		err = -EEXIST;
 		goto out;
 	}
 
-	}
-
 	/* Create a new translation entry and add to the list */
 	kref_init(&new->kref);
 	new->v = *v;
 	new->tpg = tpg;
 	new->lun = unpacked_lun;
-	list_add_tail(&new->l, head);
+	list_add_tail(&new->l, &info->v2p_entry_lists);
 
 out:
 	spin_unlock_irqrestore(&info->v2p_lock, flags);
 
 out_free:
+	if (err) {
 		mutex_lock(&tpg->tv_tpg_mutex);
 		tpg->tv_tpg_fe_count--;
 		mutex_unlock(&tpg->tv_tpg_mutex);
-
-	if (err)
 		kfree(new);
+	}
 
 	return err;
 }
@@ -956,39 +967,40 @@ static void __scsiback_del_translation_entry(struct v2p_entry *entry)
 }
 
 /*
-  Delete the translation entry specfied
+  Delete the translation entry specified
 */
 static int scsiback_del_translation_entry(struct vscsibk_info *info,
 					  struct ids_tuple *v)
 {
 	struct v2p_entry *entry;
-	struct list_head *head = &(info->v2p_entry_lists);
 	unsigned long flags;
+	int ret = 0;
 
 	spin_lock_irqsave(&info->v2p_lock, flags);
 	/* Find out the translation entry specified */
-	list_for_each_entry(entry, head, l) {
-		if ((entry->v.chn == v->chn) &&
-		    (entry->v.tgt == v->tgt) &&
-		    (entry->v.lun == v->lun)) {
-			goto found;
-		}
-	}
-
-	spin_unlock_irqrestore(&info->v2p_lock, flags);
-	return 1;
-
-found:
-	/* Delete the translation entry specfied */
+	entry = scsiback_chk_translation_entry(info, v);
+	if (entry)
 		__scsiback_del_translation_entry(entry);
+	else
+		ret = -ENOENT;
 
 	spin_unlock_irqrestore(&info->v2p_lock, flags);
-	return 0;
+	return ret;
 }
 
 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
 				char *phy, struct ids_tuple *vir, int try)
 {
+	struct v2p_entry *entry;
+	unsigned long flags;
+
+	if (try) {
+		spin_lock_irqsave(&info->v2p_lock, flags);
+		entry = scsiback_chk_translation_entry(info, vir);
+		spin_unlock_irqrestore(&info->v2p_lock, flags);
+		if (entry)
+			return;
+	}
 	if (!scsiback_add_translation_entry(info, phy, vir)) {
 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 				  "%d", XenbusStateInitialised)) {

drivers/xen/xenbus/xenbus_dev_frontend.c

@@ -188,6 +188,8 @@ static int queue_reply(struct list_head *queue, const void *data, size_t len)
 
 	if (len == 0)
 		return 0;
+	if (len > XENSTORE_PAYLOAD_MAX)
+		return -EINVAL;
 
 	rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL);
 	if (rb == NULL)