xen/events: switch user event channels to lateeoi model

commit c44b849cee8c3ac587da3b0980e01f77500d158c upstream.

Instead of disabling the irq when an event is received and enabling
it again when handled by the user process use the lateeoi model.

This is part of XSA-332.

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index e8c7f09d01be8a483df94db111faec580beb032a..bcf0b1e60f2c3aceabf56306d045188e0ec8fbfd 100644 (file)
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -178,7 +178,6 @@ static irqreturn_t evtchn_interrupt(int irq, void *data)
             "Interrupt for port %d, but apparently not enabled; per-user %p\n",
             evtchn->port, u);
 
-       disable_irq_nosync(irq);
        evtchn->enabled = false;
 
        spin_lock(&u->ring_prod_lock);
@@ -304,7 +303,7 @@ static ssize_t evtchn_write(struct file *file, const char __user *buf,
                evtchn = find_evtchn(u, port);
                if (evtchn && !evtchn->enabled) {
                        evtchn->enabled = true;
-                       enable_irq(irq_from_evtchn(port));
+                       xen_irq_lateeoi(irq_from_evtchn(port), 0);
                }
        }
 
@@ -404,8 +403,8 @@ static int evtchn_bind_to_user(struct per_user_data *u, int port)
        if (rc < 0)
                goto err;
 
-       rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, 0,
-                                      u->name, evtchn);
+       rc = bind_evtchn_to_irqhandler_lateeoi(port, evtchn_interrupt, 0,
+                                              u->name, evtchn);
        if (rc < 0)
                goto err;