Linux Virtualization - May 2020 - [PATCH V2] ifcvf: move IRQ request/free to status change handlers

On 2020/5/12 ??4:00, Zhu Lingshan wrote:
> This commit move IRQ request and free operations from probe()
> to VIRTIO status change handler to comply with VIRTIO spec.
>
> VIRTIO spec 1.1, section 2.1.2 Device Requirements: Device Status Field
> The device MUST NOT consume buffers or send any used buffer
> notifications to the driver before DRIVER_OK.

This comment needs to be checked as I said previously. It's only needed 
if we're sure ifcvf can generate interrupt before DRIVER_OK.

>
> Signed-off-by: Zhu Lingshan <lingshan.zhu at intel.com>
> ---
> changes from V1:
> remove ifcvf_stop_datapath() in status == 0 handler, we don't need to
do this
> twice; handle status == 0 after DRIVER_OK -> !DRIVER_OK handler (Jason
Wang)

Patch looks good to me, but with this patch ping cannot work on my 
machine. (It works without this patch).

Thanks

>
>   drivers/vdpa/ifcvf/ifcvf_main.c | 120
++++++++++++++++++++++++----------------
>   1 file changed, 73 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c
b/drivers/vdpa/ifcvf/ifcvf_main.c
> index abf6a061..d529ed6 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -28,6 +28,60 @@ static irqreturn_t ifcvf_intr_handler(int irq, void
*arg)
>   	return IRQ_HANDLED;
>   }
>   
> +static void ifcvf_free_irq_vectors(void *data)
> +{
> +	pci_free_irq_vectors(data);
> +}
> +
> +static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
> +{
> +	struct pci_dev *pdev = adapter->pdev;
> +	struct ifcvf_hw *vf = &adapter->vf;
> +	int i;
> +
> +
> +	for (i = 0; i < queues; i++)
> +		devm_free_irq(&pdev->dev, vf->vring[i].irq,
&vf->vring[i]);
> +
> +	ifcvf_free_irq_vectors(pdev);
> +}
> +
> +static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> +{
> +	struct pci_dev *pdev = adapter->pdev;
> +	struct ifcvf_hw *vf = &adapter->vf;
> +	int vector, i, ret, irq;
> +
> +	ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR,
> +				    IFCVF_MAX_INTR, PCI_IRQ_MSIX);
> +	if (ret < 0) {
> +		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
> +		return ret;
> +	}
> +
> +	for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
> +		snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n",
> +			 pci_name(pdev), i);
> +		vector = i + IFCVF_MSI_QUEUE_OFF;
> +		irq = pci_irq_vector(pdev, vector);
> +		ret = devm_request_irq(&pdev->dev, irq,
> +				       ifcvf_intr_handler, 0,
> +				       vf->vring[i].msix_name,
> +				       &vf->vring[i]);
> +		if (ret) {
> +			IFCVF_ERR(pdev,
> +				  "Failed to request irq for vq %d\n", i);
> +			ifcvf_free_irq(adapter, i);
> +
> +			return ret;
> +		}
> +
> +		vf->vring[i].irq = irq;
> +	}
> +
> +	return 0;
> +}
> +
>   static int ifcvf_start_datapath(void *private)
>   {
>   	struct ifcvf_hw *vf = ifcvf_private_to_vf(private);
> @@ -118,17 +172,34 @@ static void ifcvf_vdpa_set_status(struct vdpa_device
*vdpa_dev, u8 status)
>   {
>   	struct ifcvf_adapter *adapter;
>   	struct ifcvf_hw *vf;
> +	u8 status_old;
> +	int ret;
>   
>   	vf  = vdpa_to_vf(vdpa_dev);
>   	adapter = dev_get_drvdata(vdpa_dev->dev.parent);
> +	status_old = ifcvf_get_status(vf);
>   
> -	if (status == 0) {
> +	if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) &&
> +	    !(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
>   		ifcvf_stop_datapath(adapter);
> +		ifcvf_free_irq(adapter, IFCVF_MAX_QUEUE_PAIRS * 2);
> +	}
> +
> +	if (status == 0) {
>   		ifcvf_reset_vring(adapter);
>   		return;
>   	}
>   
> -	if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
> +	if ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> +	    !(status_old & VIRTIO_CONFIG_S_DRIVER_OK)) {
> +		ret = ifcvf_request_irq(adapter);
> +		if (ret) {
> +			status = ifcvf_get_status(vf);
> +			status |= VIRTIO_CONFIG_S_FAILED;
> +			ifcvf_set_status(vf, status);
> +			return;
> +		}
> +
>   		if (ifcvf_start_datapath(adapter) < 0)
>   			IFCVF_ERR(adapter->pdev,
>   				  "Failed to set ifcvf vdpa  status %u\n",
> @@ -284,38 +355,6 @@ static void ifcvf_vdpa_set_config_cb(struct
vdpa_device *vdpa_dev,
>   	.set_config_cb  = ifcvf_vdpa_set_config_cb,
>   };
>   
> -static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> -{
> -	struct pci_dev *pdev = adapter->pdev;
> -	struct ifcvf_hw *vf = &adapter->vf;
> -	int vector, i, ret, irq;
> -
> -
> -	for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++) {
> -		snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n",
> -			 pci_name(pdev), i);
> -		vector = i + IFCVF_MSI_QUEUE_OFF;
> -		irq = pci_irq_vector(pdev, vector);
> -		ret = devm_request_irq(&pdev->dev, irq,
> -				       ifcvf_intr_handler, 0,
> -				       vf->vring[i].msix_name,
> -				       &vf->vring[i]);
> -		if (ret) {
> -			IFCVF_ERR(pdev,
> -				  "Failed to request irq for vq %d\n", i);
> -			return ret;
> -		}
> -		vf->vring[i].irq = irq;
> -	}
> -
> -	return 0;
> -}
> -
> -static void ifcvf_free_irq_vectors(void *data)
> -{
> -	pci_free_irq_vectors(data);
> -}
> -
>   static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id
*id)
>   {
>   	struct device *dev = &pdev->dev;
> @@ -349,13 +388,6 @@ static int ifcvf_probe(struct pci_dev *pdev, const
struct pci_device_id *id)
>   		return ret;
>   	}
>   
> -	ret = pci_alloc_irq_vectors(pdev, IFCVF_MAX_INTR,
> -				    IFCVF_MAX_INTR, PCI_IRQ_MSIX);
> -	if (ret < 0) {
> -		IFCVF_ERR(pdev, "Failed to alloc irq vectors\n");
> -		return ret;
> -	}
> -
>   	ret = devm_add_action_or_reset(dev, ifcvf_free_irq_vectors, pdev);
>   	if (ret) {
>   		IFCVF_ERR(pdev,
> @@ -379,12 +411,6 @@ static int ifcvf_probe(struct pci_dev *pdev, const
struct pci_device_id *id)
>   	adapter->pdev = pdev;
>   	adapter->vdpa.dma_dev = &pdev->dev;
>   
> -	ret = ifcvf_request_irq(adapter);
> -	if (ret) {
> -		IFCVF_ERR(pdev, "Failed to request MSI-X irq\n");
> -		goto err;
> -	}
> -
>   	ret = ifcvf_init_hw(vf, pdev);
>   	if (ret) {
>   		IFCVF_ERR(pdev, "Failed to init IFCVF hw\n");