Re: [PATCH V2 4/5] virtio-pci: implement synchronize_vqs()

[Cornelia Huck]

On Wed, Apr 06 2022, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:

> On Wed, Apr 06, 2022 at 04:35:37PM +0800, Jason Wang wrote:
>> This patch implements PCI version of synchronize_vqs().
>> 
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
>> Cc: Marc Zyngier <maz@xxxxxxxxxx>
>> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
>
> Please add implementations at least for ccw and mmio.

I'm not sure what (if anything) can/should be done for ccw...

>
>> ---
>>  drivers/virtio/virtio_pci_common.c | 14 ++++++++++++++
>>  drivers/virtio/virtio_pci_common.h |  2 ++
>>  drivers/virtio/virtio_pci_legacy.c |  1 +
>>  drivers/virtio/virtio_pci_modern.c |  2 ++
>>  4 files changed, 19 insertions(+)
>> 
>> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
>> index d724f676608b..b78c8bc93a97 100644
>> --- a/drivers/virtio/virtio_pci_common.c
>> +++ b/drivers/virtio/virtio_pci_common.c
>> @@ -37,6 +37,20 @@ void vp_synchronize_vectors(struct virtio_device *vdev)
>>  		synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
>>  }
>>  
>> +void vp_synchronize_vqs(struct virtio_device *vdev)
>> +{
>> +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
>> +	int i;
>> +
>> +	if (vp_dev->intx_enabled) {
>> +		synchronize_irq(vp_dev->pci_dev->irq);
>> +		return;
>> +	}
>> +
>> +	for (i = 0; i < vp_dev->msix_vectors; ++i)
>> +		synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
>> +}
>> +

...given that this seems to synchronize threaded interrupt handlers?
Halil, do you think ccw needs to do anything? (AFAICS, we only have one
'irq' for channel devices anyway, and the handler just calls the
relevant callbacks directly.)

>>  /* the notify function used when creating a virt queue */
>>  bool vp_notify(struct virtqueue *vq)
>>  {