tree b9da42a7bac23a7dae425323a8ed26754f55b92f
parent c90ea7d8b3109d2a09af1791908f0edd91bbe745
author Juergen Gross <jgross@suse.com> 1541662506 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1542136622 -0800

xen: fix xen_qlock_wait()

commit d3132b3860f6cf35ff7609a76bbcdbb814bd027c upstream.

Commit a856531951dc80 ("xen: make xen_qlock_wait() nestable")
introduced a regression for Xen guests running fully virtualized
(HVM or PVH mode). The Xen hypervisor wouldn't return from the poll
hypercall with interrupts disabled in case of an interrupt (for PV
guests it does).

So instead of disabling interrupts in xen_qlock_wait() use a nesting
counter to avoid calling xen_clear_irq_pending() in case
xen_qlock_wait() is nested.

Fixes: a856531951dc80 ("xen: make xen_qlock_wait() nestable")
Cc: stable@vger.kernel.org
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>