Merge tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "This has four bug-fixes and one tiny feature that I forgot to put
  initially in my tree due to oversight.

  The feature is for kdump kernels to speed up the /proc/vmcore reading.
  There is a ram_is_pfn helper function that the different platforms can
  register for.  We are now doing that.

  The bug-fixes cover some embarrassing struct pv_cpu_ops variables
  being set to NULL on Xen (but not baremetal).  We had a similar issue
  in the past with {write|read}_msr_safe and this fills the three
  missing ones.  The other bug-fix is to make the console output (hvc)
  be capable of dealing with misbehaving backends and not fall flat on
  its face.  Lastly, a quirk for older XenBus implementations that came
  with an ancient v3.4 hypervisor (so RHEL5 based) - reading of certain
  non-existent attributes just hangs the guest during bootup - so we
  take precaution of not doing that on such older installations.

  Feature:
   - Register a pfn_is_ram helper to speed up reading of /proc/vmcore.
  Bug-fixes:
   - Three pvops call for Xen were undefined causing BUG_ONs.
   - Add a quirk so that the shutdown watches (used by kdump) are not
     used with older Xen (3.4).
   - Fix ungraceful state transition for the HVC console."

* tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.
  xen/bootup: allow {read|write}_cr8 pvops call.
  xen/bootup: allow read_tscp call for Xen PV guests.
  xen pv-on-hvm: add pfn_is_ram helper for kdump
  xen/hvc: handle backend CLOSED without CLOSING

drivers/tty/hvc/hvc_xen.c

@@ -478,7 +478,6 @@ static void xencons_backend_changed(struct xenbus_device *dev,
 	case XenbusStateInitialising:
 	case XenbusStateInitialised:
 	case XenbusStateUnknown:
-	case XenbusStateClosed:
 		break;
 
 	case XenbusStateInitWait:
@@ -488,6 +487,10 @@ static void xencons_backend_changed(struct xenbus_device *dev,
 		xenbus_switch_state(dev, XenbusStateConnected);
 		break;
 
+	case XenbusStateClosed:
+		if (dev->state == XenbusStateClosed)
+			break;
+		/* Missed the backend's CLOSING state -- fallthrough */
 	case XenbusStateClosing:
 		xenbus_frontend_closed(dev);
 		break;