xen: fixes for 4.16 rc1

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Merge tag 'for-linus-4.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:
 "Only five small fixes for issues when running under Xen"

* tag 'for-linus-4.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Fix {set,clear}_foreign_p2m_mapping on autotranslating guests
  pvcalls-back: do not return error on inet_accept EAGAIN
  xen-netfront: Fix race between device setup and open
  xen/grant-table: Use put_page instead of free_page
  x86/xen: init %gs very early to avoid page faults with stack protector

arch/x86/xen/p2m.c

@@ -694,6 +694,9 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 	int i, ret = 0;
 	pte_t *pte;
 
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return 0;
+
 	if (kmap_ops) {
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
 						kmap_ops, count);
@@ -736,6 +739,9 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 {
 	int i, ret = 0;
 
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return 0;
+
 	for (i = 0; i < count; i++) {
 		unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
 		unsigned long pfn = page_to_pfn(pages[i]);

arch/x86/xen/xen-head.S

@@ -9,7 +9,9 @@
 
 #include <asm/boot.h>
 #include <asm/asm.h>
+#include <asm/msr.h>
 #include <asm/page_types.h>
+#include <asm/percpu.h>
 #include <asm/unwind_hints.h>
 
 #include <xen/interface/elfnote.h>
@@ -35,6 +37,20 @@ ENTRY(startup_xen)
 	mov %_ASM_SI, xen_start_info
 	mov $init_thread_union+THREAD_SIZE, %_ASM_SP
 
+#ifdef CONFIG_X86_64
+	/* Set up %gs.
+	 *
+	 * The base of %gs always points to the bottom of the irqstack
+	 * union.  If the stack protector canary is enabled, it is
+	 * located at %gs:40.  Note that, on SMP, the boot cpu uses
+	 * init data section till per cpu areas are set up.
+	 */
+	movl	$MSR_GS_BASE,%ecx
+	movq	$INIT_PER_CPU_VAR(irq_stack_union),%rax
+	cdq
+	wrmsr
+#endif
+
 	jmp xen_start_kernel
 END(startup_xen)
 	__FINIT

drivers/net/xen-netfront.c

@@ -351,6 +351,9 @@ static int xennet_open(struct net_device *dev)
 	unsigned int i = 0;
 	struct netfront_queue *queue = NULL;
 
+	if (!np->queues)
+		return -ENODEV;
+
 	for (i = 0; i < num_queues; ++i) {
 		queue = &np->queues[i];
 		napi_enable(&queue->napi);
@@ -1358,18 +1361,8 @@ static int netfront_probe(struct xenbus_device *dev,
 #ifdef CONFIG_SYSFS
 	info->netdev->sysfs_groups[0] = &xennet_dev_group;
 #endif
-	err = register_netdev(info->netdev);
-	if (err) {
-		pr_warn("%s: register_netdev err=%d\n", __func__, err);
-		goto fail;
-	}
 
 	return 0;
-
- fail:
-	xennet_free_netdev(netdev);
-	dev_set_drvdata(&dev->dev, NULL);
-	return err;
 }
 
 static void xennet_end_access(int ref, void *page)
@@ -1737,8 +1730,6 @@ static void xennet_destroy_queues(struct netfront_info *info)
 {
 	unsigned int i;
 
-	rtnl_lock();
-
 	for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
 		struct netfront_queue *queue = &info->queues[i];
 
@@ -1747,8 +1738,6 @@ static void xennet_destroy_queues(struct netfront_info *info)
 		netif_napi_del(&queue->napi);
 	}
 
-	rtnl_unlock();
-
 	kfree(info->queues);
 	info->queues = NULL;
 }
@@ -1764,8 +1753,6 @@ static int xennet_create_queues(struct netfront_info *info,
 	if (!info->queues)
 		return -ENOMEM;
 
-	rtnl_lock();
-
 	for (i = 0; i < *num_queues; i++) {
 		struct netfront_queue *queue = &info->queues[i];
 
@@ -1774,7 +1761,7 @@ static int xennet_create_queues(struct netfront_info *info,
 
 		ret = xennet_init_queue(queue);
 		if (ret < 0) {
-			dev_warn(&info->netdev->dev,
+			dev_warn(&info->xbdev->dev,
 				 "only created %d queues\n", i);
 			*num_queues = i;
 			break;
@@ -1788,10 +1775,8 @@ static int xennet_create_queues(struct netfront_info *info,
 
 	netif_set_real_num_tx_queues(info->netdev, *num_queues);
 
-	rtnl_unlock();
-
 	if (*num_queues == 0) {
-		dev_err(&info->netdev->dev, "no queues\n");
+		dev_err(&info->xbdev->dev, "no queues\n");
 		return -EINVAL;
 	}
 	return 0;
@@ -1828,6 +1813,7 @@ static int talk_to_netback(struct xenbus_device *dev,
 		goto out;
 	}
 
+	rtnl_lock();
 	if (info->queues)
 		xennet_destroy_queues(info);
 
@@ -1838,6 +1824,7 @@ static int talk_to_netback(struct xenbus_device *dev,
 		info->queues = NULL;
 		goto out;
 	}
+	rtnl_unlock();
 
 	/* Create shared ring, alloc event channel -- for each queue */
 	for (i = 0; i < num_queues; ++i) {
@@ -1934,8 +1921,10 @@ abort_transaction_no_dev_fatal:
 	xenbus_transaction_end(xbt, 1);
  destroy_ring:
 	xennet_disconnect_backend(info);
+	rtnl_lock();
 	xennet_destroy_queues(info);
  out:
+	rtnl_unlock();
 	device_unregister(&dev->dev);
 	return err;
 }
@@ -1965,6 +1954,15 @@ static int xennet_connect(struct net_device *dev)
 	netdev_update_features(dev);
 	rtnl_unlock();
 
+	if (dev->reg_state == NETREG_UNINITIALIZED) {
+		err = register_netdev(dev);
+		if (err) {
+			pr_warn("%s: register_netdev err=%d\n", __func__, err);
+			device_unregister(&np->xbdev->dev);
+			return err;
+		}
+	}
+
 	/*
 	 * All public and private state should now be sane.  Get
 	 * ready to start sending and receiving packets and give the driver
@@ -2150,10 +2148,14 @@ static int xennet_remove(struct xenbus_device *dev)
 
 	xennet_disconnect_backend(info);
 
-	unregister_netdev(info->netdev);
+	if (info->netdev->reg_state == NETREG_REGISTERED)
+		unregister_netdev(info->netdev);
 
-	if (info->queues)
+	if (info->queues) {
+		rtnl_lock();
 		xennet_destroy_queues(info);
+		rtnl_unlock();
+	}
 	xennet_free_netdev(info->netdev);
 
 	return 0;

drivers/xen/grant-table.c

@@ -382,7 +382,7 @@ static void gnttab_handle_deferred(struct timer_list *unused)
 			if (entry->page) {
 				pr_debug("freeing g.e. %#x (pfn %#lx)\n",
 					 entry->ref, page_to_pfn(entry->page));
-				__free_page(entry->page);
+				put_page(entry->page);
 			} else
 				pr_info("freeing g.e. %#x\n", entry->ref);
 			kfree(entry);
@@ -438,7 +438,7 @@ void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 	if (gnttab_end_foreign_access_ref(ref, readonly)) {
 		put_free_entry(ref);
 		if (page != 0)
-			free_page(page);
+			put_page(virt_to_page(page));
 	} else
 		gnttab_add_deferred(ref, readonly,
 				    page ? virt_to_page(page) : NULL);

drivers/xen/pvcalls-back.c

@@ -548,7 +548,7 @@ static void __pvcalls_back_accept(struct work_struct *work)
 	ret = inet_accept(mappass->sock, sock, O_NONBLOCK, true);
 	if (ret == -EAGAIN) {
 		sock_release(sock);
-		goto out_error;
+		return;
 	}
 
 	map = pvcalls_new_active_socket(fedata,