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authorThomas Huth <thuth@redhat.com>2024-06-18 14:19:58 +0200
committerMichael S. Tsirkin <mst@redhat.com>2024-07-03 18:14:06 -0400
commitd72479b11797c28893e1e3fc565497a9cae5ca16 (patch)
tree48a08a9ef287d3a6548610d5346c39ed01f2eed7 /include/hw
parent0173ce4b2bb4f159f4a6d54e14adbe35f826a848 (diff)
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hw/virtio: Fix the de-initialization of vhost-user devices
The unrealize functions of the various vhost-user devices are calling the corresponding vhost_*_set_status() functions with a status of 0 to shut down the device correctly. Now these vhost_*_set_status() functions all follow this scheme: bool should_start = virtio_device_should_start(vdev, status); if (vhost_dev_is_started(&vvc->vhost_dev) == should_start) { return; } if (should_start) { /* ... do the initialization stuff ... */ } else { /* ... do the cleanup stuff ... */ } The problem here is virtio_device_should_start(vdev, 0) currently always returns "true" since it internally only looks at vdev->started instead of looking at the "status" parameter. Thus once the device got started once, virtio_device_should_start() always returns true and thus the vhost_*_set_status() functions return early, without ever doing any clean-up when being called with status == 0. This causes e.g. problems when trying to hot-plug and hot-unplug a vhost user devices multiple times since the de-initialization step is completely skipped during the unplug operation. This bug has been introduced in commit 9f6bcfd99f ("hw/virtio: move vm_running check to virtio_device_started") which replaced should_start = status & VIRTIO_CONFIG_S_DRIVER_OK; with should_start = virtio_device_started(vdev, status); which later got replaced by virtio_device_should_start(). This blocked the possibility to set should_start to false in case the status flag VIRTIO_CONFIG_S_DRIVER_OK was not set. Fix it by adjusting the virtio_device_should_start() function to only consider the status flag instead of vdev->started. Since this function is only used in the various vhost_*_set_status() functions for exactly the same purpose, it should be fine to fix it in this central place there without any risk to change the behavior of other code. Fixes: 9f6bcfd99f ("hw/virtio: move vm_running check to virtio_device_started") Buglink: https://issues.redhat.com/browse/RHEL-40708 Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <20240618121958.88673-1-thuth@redhat.com> Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'include/hw')
-rw-r--r--include/hw/virtio/virtio.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 1451926..7512afb 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -472,9 +472,9 @@ static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t status)
* @vdev - the VirtIO device
* @status - the devices status bits
*
- * This is similar to virtio_device_started() but also encapsulates a
- * check on the VM status which would prevent a device starting
- * anyway.
+ * This is similar to virtio_device_started() but ignores vdev->started
+ * and also encapsulates a check on the VM status which would prevent a
+ * device from starting anyway.
*/
static inline bool virtio_device_should_start(VirtIODevice *vdev, uint8_t status)
{
@@ -482,7 +482,7 @@ static inline bool virtio_device_should_start(VirtIODevice *vdev, uint8_t status
return false;
}
- return virtio_device_started(vdev, status);
+ return status & VIRTIO_CONFIG_S_DRIVER_OK;
}
static inline void virtio_set_started(VirtIODevice *vdev, bool started)