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 f4edd6df3df235c55aef1329cb8e17b5ae8cf9f7..96c3007576b62ecfc076aa6fd81f9ebc43ce3fe3 100644 (file)
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -173,7 +173,6 @@ 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);
@@ -299,7 +298,7 @@ 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);
                }
        }
 
@@ -399,8 +398,8 @@ 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;