From e4631c00d8e9ee3608ef3196cbe8bec4841ee988 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Wed, 8 Jan 2020 15:04:57 +0000
Subject: [PATCH 2/5] vfio/pci: Don't remove irqchip notifier if not registered

RH-Author: Peter Xu <peterx@redhat.com>
Message-id: <20200108150457.12324-2-peterx@redhat.com>
Patchwork-id: 93291
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 1/1] vfio/pci: Don't remove irqchip notifier if not registered
Bugzilla: 1782678
RH-Acked-by: Alex Williamson <alex.williamson@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
RH-Acked-by: Auger Eric <eric.auger@redhat.com>
RH-Acked-by: Jens Freimann <jfreimann@redhat.com>

The kvm irqchip notifier is only registered if the device supports
INTx, however it's unconditionally removed.  If the assigned device
does not support INTx, this will cause QEMU to crash when unplugging
the device from the system.  Change it to conditionally remove the
notifier only if the notify hook is setup.

CC: Eduardo Habkost <ehabkost@redhat.com>
CC: David Gibson <david@gibson.dropbear.id.au>
CC: Alex Williamson <alex.williamson@redhat.com>
Cc: qemu-stable@nongnu.org # v4.2
Reported-by: yanghliu@redhat.com
Debugged-by: Eduardo Habkost <ehabkost@redhat.com>
Fixes: c5478fea27ac ("vfio/pci: Respond to KVM irqchip change notifier")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1782678
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
(cherry picked from commit 0446f8121723b134ca1d1ed0b73e96d4a0a8689d)
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 hw/vfio/pci.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 309535f..d717520 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3100,7 +3100,9 @@ static void vfio_exitfn(PCIDevice *pdev)
     vfio_unregister_req_notifier(vdev);
     vfio_unregister_err_notifier(vdev);
     pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
-    kvm_irqchip_remove_change_notifier(&vdev->irqchip_change_notifier);
+    if (vdev->irqchip_change_notifier.notify) {
+        kvm_irqchip_remove_change_notifier(&vdev->irqchip_change_notifier);
+    }
     vfio_disable_interrupts(vdev);
     if (vdev->intx.mmap_timer) {
         timer_free(vdev->intx.mmap_timer);
-- 
1.8.3.1