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[Qemu-devel] [PATCH v2] vhost: Update 'ioeventfd_started' with host noti
From: |
Felipe Franciosi |
Subject: |
[Qemu-devel] [PATCH v2] vhost: Update 'ioeventfd_started' with host notifiers |
Date: |
Wed, 9 Nov 2016 04:44:36 -0800 |
Following the recent refactor of virtio notfiers [1], more specifically
the patch that uses virtio_bus_set_host_notifier [2] by default, core
virtio code requires 'ioeventfd_started' to be set to true/false when
the host notifiers are configured. Because not all vhost devices were
update (eg. vhost-scsi) to use the new interface, this value is always
set to false.
When booting a guest with a vhost-scsi backend controller, SeaBIOS will
initially configure the device which sets all notifiers. The guest will
continue to boot fine until the kernel virtio-scsi driver reinitialises
the device causing a stop followed by another start. Since
ioeventfd_started was never set to true, the 'stop' operation triggered
by virtio_bus_set_host_notifier() will not result in a call to
virtio_pci_ioeventfd_assign(assign=false). This leaves the memory
regions with stale notifiers and results on the next start triggering
the following assertion:
kvm_mem_ioeventfd_add: error adding ioeventfd: File exists
Aborted
This patch updates ioeventfd_started whenever the notifiers are set or
cleared, fixing this issue.
Signed-off-by: Felipe Franciosi <address@hidden>
[1] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07748.html
[2] http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg07760.html
---
v1->v2:
- Update ioeventfd_started in vhost_dev_enable/disable_notifiers()
instead of vhost_scsi_start/stop().
- Reword the commit message accordingly.
---
hw/virtio/vhost.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 131f164..1290963 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1205,6 +1205,7 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev,
VirtIODevice *vdev)
goto fail_vq;
}
}
+ VIRTIO_BUS(qbus)->ioeventfd_started = true;
return 0;
fail_vq:
@@ -1239,6 +1240,7 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev,
VirtIODevice *vdev)
}
assert (r >= 0);
}
+ VIRTIO_BUS(qbus)->ioeventfd_started = false;
virtio_device_start_ioeventfd(vdev);
}
--
1.9.4
- [Qemu-devel] [PATCH v2] vhost: Update 'ioeventfd_started' with host notifiers,
Felipe Franciosi <=