Re: [PATCH v4 10/22] hw/virtio: move vm_running check to virtio_device_started

[Alex Bennée]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Tue, Aug 02, 2022 at 10:49:58AM +0100, Alex Bennée wrote:
>> 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>
>
> How bad is it if we drop this?


I assume it will break gpio. Why do we want to drop this now? It has
been merged awhile. However there was a follow-up patch which tweaked
the order of checks in virtio_device_started.

>
>> ---
>>  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;
>>      }
>> -- 
>> 2.30.2


-- 
Alex Bennée