Merge tag 'for-linus-7.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:

 - fix an error path in drivers/xen/manage.c

 - fix the Xen console driver solving a boot hangup when the console
   backend isn't yet running

 - comment fix in the Xen swiotlb driver

 - hardening for Xen on Arm adding a more thorough validation

 - cleanup of the Xen grant table code hiding suspend/resume code for
   the case if CONFIG_HIBERNATE_CALLBACKS isn't defined

* tag 'for-linus-7.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/grant-table: guard gnttab_suspend/resume with CONFIG_HIBERNATE_CALLBACKS
  hvc/xen: Check console connection flag
  xen/swiotlb: fix stale reference to swiotlb_unmap_page()
  xen/manage: unwind partial shutdown watcher setup on error
  ARM: xen: validate hypervisor compatible before parsing its version

7 files changed, 54 insertions, 9 deletions

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 4feed2c2498d..25a0ce3b4584 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -218,8 +218,9 @@ static __initdata struct {
 static int __init fdt_find_hyper_node(unsigned long node, const char *uname,
 				      int depth, void *data)
 {
-	const void *s = NULL;
+	const char *s = NULL;
 	int len;
+	size_t prefix_len = strlen(hyper_node.prefix);
 
 	if (depth != 1 || strcmp(uname, "hypervisor") != 0)
 		return 0;
@@ -228,9 +229,10 @@ static int __init fdt_find_hyper_node(unsigned long node, const char *uname,
 		hyper_node.found = true;
 
 	s = of_get_flat_dt_prop(node, "compatible", &len);
-	if (strlen(hyper_node.prefix) + 3  < len &&
-	    !strncmp(hyper_node.prefix, s, strlen(hyper_node.prefix)))
-		hyper_node.version = s + strlen(hyper_node.prefix);
+	if (s && len > 0 && strnlen(s, len) < len &&
+	    len > prefix_len + 3 &&
+	    !strncmp(hyper_node.prefix, s, prefix_len))
+		hyper_node.version = s + prefix_len;
 
 	/*
 	 * Check if Xen supports EFI by checking whether there is the
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 7f0b6262488c..c407592442cd 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -139,6 +139,9 @@ static ssize_t domU_write_console(uint32_t vtermno, const u8 *data, size_t len)
 	if (cons == NULL)
 		return -EINVAL;
 
+	if (cons->intf->connection == XENCONSOLE_DISCONNECTED)
+		return -ENOTCONN;
+
 	/*
 	 * Make sure the whole buffer is emitted, polling if
 	 * necessary.  We don't ever want to rely on the hvc daemon
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 97e27f754d39..a6abf1ccd54c 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -1579,7 +1579,7 @@ static int gnttab_setup(void)
 	}
 	return gnttab_map(0, nr_grant_frames - 1);
 }
-
+#ifdef CONFIG_HIBERNATE_CALLBACKS
 int gnttab_resume(void)
 {
 	gnttab_request_version();
@@ -1592,6 +1592,7 @@ int gnttab_suspend(void)
 		gnttab_interface->unmap_frames();
 	return 0;
 }
+#endif
 
 static int gnttab_expand(unsigned int req_entries)
 {
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index e20c40a62e64..05d7de128e71 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -343,12 +343,11 @@ static int setup_shutdown_watcher(void)
 		return err;
 	}
 
-
 #ifdef CONFIG_MAGIC_SYSRQ
 	err = register_xenbus_watch(&sysrq_watch);
 	if (err) {
 		pr_err("Failed to set sysrq watcher\n");
-		return err;
+		goto err_unregister_shutdown;
 	}
 #endif
 
@@ -361,11 +360,26 @@ static int setup_shutdown_watcher(void)
 		if (err) {
 			pr_err("%s: Error %d writing %s\n", __func__,
 				err, node);
-			return err;
+			goto err_remove_features;
 		}
 	}
 
 	return 0;
+
+err_remove_features:
+	while (--idx >= 0) {
+		if (!shutdown_handlers[idx].flag)
+			continue;
+		snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
+			 shutdown_handlers[idx].command);
+		xenbus_rm(XBT_NIL, "control", node);
+	}
+#ifdef CONFIG_MAGIC_SYSRQ
+	unregister_xenbus_watch(&sysrq_watch);
+err_unregister_shutdown:
+#endif
+	unregister_xenbus_watch(&shutdown_watch);
+	return err;
 }
 
 static int shutdown_event(struct notifier_block *notifier,
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index ccf25027bec1..4a734ee38994 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -340,7 +340,7 @@ xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
 
 /*
  * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
- * concerning calls here are the same as for swiotlb_unmap_phys() above.
+ * concerning calls here are the same as for xen_swiotlb_unmap_phys() above.
  */
 static void
 xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 69ac6d80a006..a33a60a2ea72 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -84,8 +84,20 @@ struct gntab_unmap_queue_data
 };
 
 int gnttab_init(void);
+#ifdef CONFIG_HIBERNATE_CALLBACKS
 int gnttab_suspend(void);
 int gnttab_resume(void);
+#else
+static inline int gnttab_suspend(void)
+{
+	return 0;
+}
+
+static inline int gnttab_resume(void)
+{
+	return 0;
+}
+#endif
 
 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 				int readonly);
diff --git a/include/xen/interface/io/console.h b/include/xen/interface/io/console.h
index cf17e89ed861..687949bdebb1 100644
--- a/include/xen/interface/io/console.h
+++ b/include/xen/interface/io/console.h
@@ -19,6 +19,19 @@ struct xencons_interface {
     char out[2048];
     XENCONS_RING_IDX in_cons, in_prod;
     XENCONS_RING_IDX out_cons, out_prod;
+/*
+ * Flag values signaling from backend to frontend whether the console is
+ * connected.  i.e. Whether it will be serviced and emptied.
+ *
+ * The flag starts as disconnected.
+ */
+#define XENCONSOLE_DISCONNECTED 1
+/*
+ * The flag is set to connected when the backend connects and the console
+ * will be serviced.
+ */
+#define XENCONSOLE_CONNECTED    0
+    uint8_t connection;
 };
 
 #endif /* __XEN_PUBLIC_IO_CONSOLE_H__ */