Re: [PULL 07/55] hw/virtio: move vm_running check to virtio_device_started

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Oct 10, 2022 at 01:29:10PM -0400, Michael S. Tsirkin wrote:
> From: Alex Bennée <alex.bennee@linaro.org>
> 
> All the boilerplate virtio code does the same thing (or should at
> least) of checking to see if the VM is running before attempting to
> start VirtIO. Push the logic up to the common function to avoid
> getting a copy and paste wrong.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Message-Id: <20220802095010.3330793-11-alex.bennee@linaro.org>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

So, looking at the resulting code, I missed the fact that this function
is also used in virtio core.  So this patch does not do what it's saying
it does (just refactor code).
Instead it completely changes the meaning for virtio core.
I thunk we should revert upstream, however, gpio has grown a
dependency on this since then.
Alex, could you take a look please?

> ---
>  include/hw/virtio/virtio.h   | 5 +++++
>  hw/virtio/vhost-user-fs.c    | 6 +-----
>  hw/virtio/vhost-user-i2c.c   | 6 +-----
>  hw/virtio/vhost-user-rng.c   | 6 +-----
>  hw/virtio/vhost-user-vsock.c | 6 +-----
>  hw/virtio/vhost-vsock.c      | 6 +-----
>  6 files changed, 10 insertions(+), 25 deletions(-)
> 
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 9bb2485415..74e7ad5a92 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -100,6 +100,7 @@ struct VirtIODevice
>      VirtQueue *vq;
>      MemoryListener listener;
>      uint16_t device_id;
> +    /* @vm_running: current VM running state via virtio_vmstate_change() */
>      bool vm_running;
>      bool broken; /* device in invalid state, needs reset */
>      bool use_disabled_flag; /* allow use of 'disable' flag when needed */
> @@ -376,6 +377,10 @@ static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t status)
>          return vdev->started;
>      }
>  
> +    if (!vdev->vm_running) {
> +        return false;
> +    }
> +
>      return status & VIRTIO_CONFIG_S_DRIVER_OK;
>  }
>  
> diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
> index e513e4fdda..d2bebba785 100644
> --- a/hw/virtio/vhost-user-fs.c
> +++ b/hw/virtio/vhost-user-fs.c
> @@ -122,11 +122,7 @@ static void vuf_stop(VirtIODevice *vdev)
>  static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostUserFS *fs = VHOST_USER_FS(vdev);
> -    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> -
> -    if (!vdev->vm_running) {
> -        should_start = false;
> -    }
> +    bool should_start = virtio_device_started(vdev, status);
>  
>      if (fs->vhost_dev.started == should_start) {
>          return;
> diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c
> index 6020eee093..b930cf6d5e 100644
> --- a/hw/virtio/vhost-user-i2c.c
> +++ b/hw/virtio/vhost-user-i2c.c
> @@ -93,11 +93,7 @@ static void vu_i2c_stop(VirtIODevice *vdev)
>  static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
> -    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> -
> -    if (!vdev->vm_running) {
> -        should_start = false;
> -    }
> +    bool should_start = virtio_device_started(vdev, status);
>  
>      if (i2c->vhost_dev.started == should_start) {
>          return;
> diff --git a/hw/virtio/vhost-user-rng.c b/hw/virtio/vhost-user-rng.c
> index 3a7bf8e32d..a9c1c4bc79 100644
> --- a/hw/virtio/vhost-user-rng.c
> +++ b/hw/virtio/vhost-user-rng.c
> @@ -90,11 +90,7 @@ static void vu_rng_stop(VirtIODevice *vdev)
>  static void vu_rng_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostUserRNG *rng = VHOST_USER_RNG(vdev);
> -    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> -
> -    if (!vdev->vm_running) {
> -        should_start = false;
> -    }
> +    bool should_start = virtio_device_started(vdev, status);
>  
>      if (rng->vhost_dev.started == should_start) {
>          return;
> diff --git a/hw/virtio/vhost-user-vsock.c b/hw/virtio/vhost-user-vsock.c
> index 0f8ff99f85..22c1616ebd 100644
> --- a/hw/virtio/vhost-user-vsock.c
> +++ b/hw/virtio/vhost-user-vsock.c
> @@ -55,11 +55,7 @@ const VhostDevConfigOps vsock_ops = {
>  static void vuv_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
> -    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> -
> -    if (!vdev->vm_running) {
> -        should_start = false;
> -    }
> +    bool should_start = virtio_device_started(vdev, status);
>  
>      if (vvc->vhost_dev.started == should_start) {
>          return;
> diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
> index 0338de892f..8031c164a5 100644
> --- a/hw/virtio/vhost-vsock.c
> +++ b/hw/virtio/vhost-vsock.c
> @@ -70,13 +70,9 @@ static int vhost_vsock_set_running(VirtIODevice *vdev, int start)
>  static void vhost_vsock_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
> -    bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> +    bool should_start = virtio_device_started(vdev, status);
>      int ret;
>  
> -    if (!vdev->vm_running) {
> -        should_start = false;
> -    }
> -
>      if (vvc->vhost_dev.started == should_start) {
>          return;
>      }
> -- 
> MST
>