* [Qemu-devel] question on virtio ccw
@ 2017-12-07 17:18 Michael S. Tsirkin
2017-12-08 10:08 ` Cornelia Huck
0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2017-12-07 17:18 UTC (permalink / raw)
To: Cornelia Huck; +Cc: qemu-devel
I see this in ccw in qemu:
if (virtio_set_status(vdev, status) == 0) {
if (vdev->status == 0) {
virtio_ccw_reset_virtio(dev, vdev);
}
if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
virtio_ccw_start_ioeventfd(dev);
}
sch->curr_status.scsw.count = ccw.count - sizeof(status);
ret = 0;
} else {
/* Trigger a command reject. */
ret = -ENOSYS;
}
virtio_set_status on success sets vdev->status to status.
Why check vdev->status in one place and status in another?
--
MST
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [Qemu-devel] question on virtio ccw
2017-12-07 17:18 [Qemu-devel] question on virtio ccw Michael S. Tsirkin
@ 2017-12-08 10:08 ` Cornelia Huck
0 siblings, 0 replies; 2+ messages in thread
From: Cornelia Huck @ 2017-12-08 10:08 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: qemu-devel
On Thu, 7 Dec 2017 19:18:44 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> I see this in ccw in qemu:
>
> if (virtio_set_status(vdev, status) == 0) {
> if (vdev->status == 0) {
> virtio_ccw_reset_virtio(dev, vdev);
> }
> if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
> virtio_ccw_start_ioeventfd(dev);
> }
> sch->curr_status.scsw.count = ccw.count - sizeof(status);
> ret = 0;
> } else {
> /* Trigger a command reject. */
> ret = -ENOSYS;
> }
>
> virtio_set_status on success sets vdev->status to status.
> Why check vdev->status in one place and status in another?
>
Probably for symmetry with the check whether to stop ioeventfd right
above. But it does not really matter one way or the other.
^ permalink raw reply [flat|nested] 2+ messages in thread
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