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| author | Hanna Czenczek <hreitz@redhat.com> | 2024-07-23 18:39:40 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2024-09-10 14:27:56 -0400 |
| commit | 2688e8df60f5a655dc34c5e38523e425556f8483 (patch) | |
| tree | 75021aa723ce8f60ce9dac63d90b204b8a28cd90 /hw | |
| parent | 00adced5c3166ee65b6880b48c1e0826b7304f76 (diff) | |
| download | qemu-2688e8df60f5a655dc34c5e38523e425556f8483.zip qemu-2688e8df60f5a655dc34c5e38523e425556f8483.tar.gz qemu-2688e8df60f5a655dc34c5e38523e425556f8483.tar.bz2 | |
virtio: Always reset vhost devices
Requiring `vhost_started` to be true for resetting vhost devices in
`virtio_reset()` seems like the wrong condition: Most importantly, the
preceding `virtio_set_status(vdev, 0)` call will (for vhost devices) end
up in `vhost_dev_stop()` (through vhost devices' `.set_status`
implementations), setting `vdev->vhost_started = false`. Therefore, the
gated `vhost_reset_device()` call is unreachable.
`vhost_started` is not documented, so it is hard to say what exactly it
is supposed to mean, but judging from the fact that `vhost_dev_start()`
sets it and `vhost_dev_stop()` clears it, it seems like it indicates
whether there is a vhost back-end, and whether that back-end is
currently running and processing virtio requests.
Making a reset conditional on whether the vhost back-end is processing
virtio requests seems wrong; in fact, it is probably better to reset it
only when it is not currently processing requests, which is exactly the
current order of operations in `virtio_reset()`: First, the back-end is
stopped through `virtio_set_status(vdev, 0)`, then we want to send a
reset.
Therefore, we should drop the `vhost_started` condition, but in its
stead we then have to verify that we can indeed send a reset to this
vhost device, by not just checking `k->get_vhost != NULL` (introduced by
commit 95e1019a4a9), but also that the vhost back-end is connected
(`hdev = k->get_vhost(); hdev != NULL && hdev->vhost_ops != NULL`).
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20240723163941.48775-3-hreitz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/virtio/virtio.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 9e10cbc..42589ad 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2331,8 +2331,12 @@ void virtio_reset(void *opaque) vdev->device_endian = virtio_default_endian(); } - if (vdev->vhost_started && k->get_vhost) { - vhost_reset_device(k->get_vhost(vdev)); + if (k->get_vhost) { + struct vhost_dev *hdev = k->get_vhost(vdev); + /* Only reset when vhost back-end is connected */ + if (hdev && hdev->vhost_ops) { + vhost_reset_device(hdev); + } } if (k->reset) { |