xen: branch for v5.7-rc2

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Merge tag 'for-linus-5.7-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen update from Juergen Gross:

 - a small cleanup patch

 - a security fix for a bug in the Xen hypervisor to avoid enabling Xen
   guests to crash dom0 on an unfixed hypervisor.

* tag 'for-linus-5.7-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  arm/xen: make _xen_start_info static
  xen/xenbus: ensure xenbus_map_ring_valloc() returns proper grant status

arch/arm/xen/enlighten.c

@@ -36,7 +36,7 @@
 
 #include <linux/mm.h>
 
-struct start_info _xen_start_info;
+static struct start_info _xen_start_info;
 struct start_info *xen_start_info = &_xen_start_info;
 EXPORT_SYMBOL(xen_start_info);
 

drivers/xen/xenbus/xenbus_client.c

@@ -448,7 +448,14 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
 			   unsigned int nr_grefs, void **vaddr)
 {
-	return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
+	int err;
+
+	err = ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
+	/* Some hypervisors are buggy and can return 1. */
+	if (err > 0)
+		err = GNTST_general_error;
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);