Subject: Re: [PATCH V4 4/4] vDPA/ifcvf: implement shared IRQ feature

From: "Michael S. Tsirkin" <[email-masked]>
Date: Mon, 14 Feb 2022 09:25:23 -0500

On Mon, Feb 14, 2022 at 03:19:25PM +0800, Jason Wang wrote:
> 
> 在 2022/2/3 下午3:27, Zhu Lingshan 写道:
> > On some platforms/devices, there may not be enough MSI vector
> > slots allocated for virtqueues and config changes. In such a case,
> > the interrupt sources(virtqueues, config changes) must share
> > an IRQ/vector, to avoid initialization failures, keep
> > the device functional.
> > 
> > This commit handles three cases:
> > (1) number of the allocated vectors == the number of virtqueues + 1
> > (config changes), every virtqueue and the config interrupt has
> > a separated vector/IRQ, the best and the most likely case.
> > (2) number of the allocated vectors is less than the best case, but
> > greater than 1. In this case, all virtqueues share a vector/IRQ,
> > the config interrupt has a separated vector/IRQ
> > (3) only one vector is allocated, in this case, the virtqueues and
> > the config interrupt share a vector/IRQ. The worst and most
> > unlikely case.
> > 
> > Otherwise, it needs to fail.
> > 
> > This commit introduces some helper functions:
> > ifcvf_set_vq_vector() and ifcvf_set_config_vector() sets virtqueue
> > vector and config vector in the device config space, so that
> > the device can send interrupt DMA.
> > 
> > This commit adds some fields in struct ifcvf_hw and re-placed
> > the existed fields to be aligned with the cacheline.
> > 
> > Signed-off-by: Zhu Lingshan <[email-masked]>
> > ---
> >   drivers/vdpa/ifcvf/ifcvf_base.c |  47 ++++--
> >   drivers/vdpa/ifcvf/ifcvf_base.h |  23 ++-
> >   drivers/vdpa/ifcvf/ifcvf_main.c | 243 +++++++++++++++++++++++++++-----
> >   3 files changed, 256 insertions(+), 57 deletions(-)
> > 
> > diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
> > index 397692ae671c..18dcb63ab1e3 100644
> > --- a/drivers/vdpa/ifcvf/ifcvf_base.c
> > +++ b/drivers/vdpa/ifcvf/ifcvf_base.c
> > @@ -15,6 +15,36 @@ struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw)
> >   	return container_of(hw, struct ifcvf_adapter, vf);
> >   }
> > +int ifcvf_set_vq_vector(struct ifcvf_hw *hw, u16 qid, int vector)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
> > +	struct ifcvf_adapter *ifcvf = vf_to_adapter(hw);
> > +
> > +	ifc_iowrite16(qid, &cfg->queue_select);
> > +	ifc_iowrite16(vector, &cfg->queue_msix_vector);
> > +	if (ifc_ioread16(&cfg->queue_msix_vector) == VIRTIO_MSI_NO_VECTOR) {
> > +		IFCVF_ERR(ifcvf->pdev, "No msix vector for queue %u\n", qid);
> > +			return -EINVAL;
> > +	}
> 
> 
> Let's leave this check for the caller, E.g can caller try to assign
> NO_VECTOR during uni-nit?

Hmm I'm not sure I agree. Caller will have to write queue select
again, and that's an extra IO, which is a waste.
And having function checking itself just seems better contained.

> 
> > +
> > +	return 0;
> > +}
> > +
> > +int ifcvf_set_config_vector(struct ifcvf_hw *hw, int vector)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
> > +	struct ifcvf_adapter *ifcvf = vf_to_adapter(hw);
> > +
> > +	cfg = hw->common_cfg;
> > +	ifc_iowrite16(vector,  &cfg->msix_config);
> > +	if (ifc_ioread16(&cfg->msix_config) == VIRTIO_MSI_NO_VECTOR) {
> > +		IFCVF_ERR(ifcvf->pdev, "No msix vector for device config\n");
> > +		return -EINVAL;
> > +	}
> 
> 
> Similar question as above.
> 
> 
> > +
> > +	return 0;
> > +}
> > +
> >   static void __iomem *get_cap_addr(struct ifcvf_hw *hw,
> >   				  struct virtio_pci_cap *cap)
> >   {
> > @@ -140,6 +170,8 @@ int ifcvf_init_hw(struct ifcvf_hw *hw, struct pci_dev *pdev)
> >   		  hw->common_cfg, hw->notify_base, hw->isr,
> >   		  hw->dev_cfg, hw->notify_off_multiplier);
> > +	hw->vqs_shared_irq = -EINVAL;
> > +
> >   	return 0;
> >   }
> > @@ -321,12 +353,6 @@ static int ifcvf_hw_enable(struct ifcvf_hw *hw)
> >   	ifcvf = vf_to_adapter(hw);
> >   	cfg = hw->common_cfg;
> > -	ifc_iowrite16(IFCVF_MSI_CONFIG_OFF, &cfg->msix_config);
> > -
> > -	if (ifc_ioread16(&cfg->msix_config) == VIRTIO_MSI_NO_VECTOR) {
> > -		IFCVF_ERR(ifcvf->pdev, "No msix vector for device config\n");
> > -		return -EINVAL;
> > -	}
> >   	for (i = 0; i < hw->nr_vring; i++) {
> >   		if (!hw->vring[i].ready)
> > @@ -340,15 +366,6 @@ static int ifcvf_hw_enable(struct ifcvf_hw *hw)
> >   		ifc_iowrite64_twopart(hw->vring[i].used, &cfg->queue_used_lo,
> >   				     &cfg->queue_used_hi);
> >   		ifc_iowrite16(hw->vring[i].size, &cfg->queue_size);
> > -		ifc_iowrite16(i + IFCVF_MSI_QUEUE_OFF, &cfg->queue_msix_vector);
> > -
> > -		if (ifc_ioread16(&cfg->queue_msix_vector) ==
> > -		    VIRTIO_MSI_NO_VECTOR) {
> > -			IFCVF_ERR(ifcvf->pdev,
> > -				  "No msix vector for queue %u\n", i);
> > -			return -EINVAL;
> > -		}
> > -
> >   		ifcvf_set_vq_state(hw, i, hw->vring[i].last_avail_idx);
> >   		ifc_iowrite16(1, &cfg->queue_enable);
> >   	}
> > diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h
> > index 949b4fb9d554..9cfe088c82e9 100644
> > --- a/drivers/vdpa/ifcvf/ifcvf_base.h
> > +++ b/drivers/vdpa/ifcvf/ifcvf_base.h
> > @@ -27,8 +27,6 @@
> >   #define IFCVF_QUEUE_ALIGNMENT	PAGE_SIZE
> >   #define IFCVF_QUEUE_MAX		32768
> > -#define IFCVF_MSI_CONFIG_OFF	0
> > -#define IFCVF_MSI_QUEUE_OFF	1
> >   #define IFCVF_PCI_MAX_RESOURCE	6
> >   #define IFCVF_LM_CFG_SIZE		0x40
> > @@ -42,6 +40,13 @@
> >   #define ifcvf_private_to_vf(adapter) \
> >   	(&((struct ifcvf_adapter *)adapter)->vf)
> > +/* all vqs and config interrupt has its own vector */
> > +#define MSIX_VECTOR_PER_VQ_AND_CONFIG		1
> > +/* all vqs share a vector, and config interrupt has a separate vector */
> > +#define MSIX_VECTOR_SHARED_VQ_AND_CONFIG	2
> > +/* all vqs and config interrupt share a vector */
> > +#define MSIX_VECTOR_DEV_SHARED			3
> 
> 
> I think there's no much value to differ 2 from 3 consider config interrupt
> should be rare.

Yes but if we do not have a dedicated vector then we need an
extra device IO (in fact, a read) on each interrupt.

> 
> > +
> >   static inline u8 ifc_ioread8(u8 __iomem *addr)
> >   {
> >   	return ioread8(addr);
> > @@ -97,25 +102,27 @@ struct ifcvf_hw {
> >   	u8 __iomem *isr;
> >   	/* Live migration */
> >   	u8 __iomem *lm_cfg;
> > -	u16 nr_vring;
> 
> 
> Any reason for moving nv_vring, config_size, and other stuffs?
> 
> 
> >   	/* Notification bar number */
> >   	u8 notify_bar;
> > +	u8 msix_vector_status;
> > +	/* virtio-net or virtio-blk device config size */
> > +	u32 config_size;
> >   	/* Notificaiton bar address */
> >   	void __iomem *notify_base;
> >   	phys_addr_t notify_base_pa;
> >   	u32 notify_off_multiplier;
> > +	u32 dev_type;
> >   	u64 req_features;
> >   	u64 hw_features;
> > -	u32 dev_type;
> >   	struct virtio_pci_common_cfg __iomem *common_cfg;
> >   	void __iomem *dev_cfg;
> >   	struct vring_info vring[IFCVF_MAX_QUEUES];
> >   	void __iomem * const *base;
> >   	char config_msix_name[256];
> >   	struct vdpa_callback config_cb;
> > -	unsigned int config_irq;
> > -	/* virtio-net or virtio-blk device config size */
> > -	u32 config_size;
> > +	int config_irq;
> > +	int vqs_shared_irq;
> > +	u16 nr_vring;
> >   };
> >   struct ifcvf_adapter {
> > @@ -160,4 +167,6 @@ int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num);
> >   struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw);
> >   int ifcvf_probed_virtio_net(struct ifcvf_hw *hw);
> >   u32 ifcvf_get_config_size(struct ifcvf_hw *hw);
> > +int ifcvf_set_vq_vector(struct ifcvf_hw *hw, u16 qid, int vector);
> > +int ifcvf_set_config_vector(struct ifcvf_hw *hw, int vector);
> >   #endif /* _IFCVF_H_ */
> > diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> > index 44c89ab0b6da..ca414399f040 100644
> > --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> > +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> > @@ -17,6 +17,7 @@
> >   #define DRIVER_AUTHOR   "Intel Corporation"
> >   #define IFCVF_DRIVER_NAME       "ifcvf"
> > +/* handles config interrupt */
> 
> 
> This seems unrelated to the shared IRQ logic and it looks useless since it's
> easily to deduce it from the function name below.
> 
> 
> >   static irqreturn_t ifcvf_config_changed(int irq, void *arg)
> >   {
> >   	struct ifcvf_hw *vf = arg;
> > @@ -27,6 +28,7 @@ static irqreturn_t ifcvf_config_changed(int irq, void *arg)
> >   	return IRQ_HANDLED;
> >   }
> > +/* handles vqs interrupt */
> 
> 
> So did this.
> 
> 
> >   static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
> >   {
> >   	struct vring_info *vring = arg;
> > @@ -37,24 +39,78 @@ static irqreturn_t ifcvf_intr_handler(int irq, void *arg)
> >   	return IRQ_HANDLED;
> >   }
> > +/* handls vqs shared interrupt */
> > +static irqreturn_t ifcvf_vq_shared_intr_handler(int irq, void *arg)
> > +{
> > +	struct ifcvf_hw *vf = arg;
> > +	struct vring_info *vring;
> > +	int i;
> > +
> > +	for (i = 0; i < vf->nr_vring; i++) {
> > +		vring = &vf->vring[i];
> > +		if (vring->cb.callback)
> > +			vf->vring->cb.callback(vring->cb.private);
> > +	}
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +/* handles a shared interrupt for vqs and config */
> > +static irqreturn_t ifcvf_dev_shared_intr_handler(int irq, void *arg)

shared is not a good name given IRQ_SHARED is not set.
maybe "common"? "reused"?

> > +{
> > +	struct ifcvf_hw *vf = arg;
> > +	u8 isr;
> > +
> > +	isr = ifc_ioread8(vf->isr);
> 
> 
> We need to exactly what vp_interrupt do here. Checking against vf->isr first
> and return IRQ_NONE if it is not set.

no, vf->isr is not set for VQ interrupts. If need to actually poke
at the VQ to know.

> Always return IRQ_HANDLED will break the device who shares an irq with
> IFCVF.

It's a MSI, not INT#. So interrupt is not shared as such - it's only
sharing vector between config and vq.

> 
> > +	if (isr & VIRTIO_PCI_ISR_CONFIG)
> > +		ifcvf_config_changed(irq, arg);
> > +
> > +	return ifcvf_vq_shared_intr_handler(irq, arg);
> > +}
> > +
> >   static void ifcvf_free_irq_vectors(void *data)
> >   {
> >   	pci_free_irq_vectors(data);
> >   }
> > -static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
> > +static void ifcvf_free_vq_irq(struct ifcvf_adapter *adapter, int queues)
> >   {
> >   	struct pci_dev *pdev = adapter->pdev;
> >   	struct ifcvf_hw *vf = &adapter->vf;
> >   	int i;
> > +	if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG) {
> > +		for (i = 0; i < queues; i++) {
> > +			devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]);
> > +			vf->vring[i].irq = -EINVAL;
> > +		}
> > +	} else {
> > +		devm_free_irq(&pdev->dev, vf->vqs_shared_irq, vf);
> > +		vf->vqs_shared_irq = -EINVAL;
> > +	}
> > +}
> > -	for (i = 0; i < queues; i++) {
> > -		devm_free_irq(&pdev->dev, vf->vring[i].irq, &vf->vring[i]);
> > -		vf->vring[i].irq = -EINVAL;
> > +static void ifcvf_free_config_irq(struct ifcvf_adapter *adapter)
> > +{
> > +	struct pci_dev *pdev = adapter->pdev;
> > +	struct ifcvf_hw *vf = &adapter->vf;
> > +
> > +	/* If the irq is shared by all vqs and the config interrupt,
> > +	 * it is already freed in ifcvf_free_vq_irq, so here only
> > +	 * need to free config irq when msix_vector_status != MSIX_VECTOR_DEV_SHARED
> > +	 */
> > +	if (vf->msix_vector_status != MSIX_VECTOR_DEV_SHARED) {
> > +		devm_free_irq(&pdev->dev, vf->config_irq, vf);
> > +		vf->config_irq = -EINVAL;
> >   	}
> > +}
> > +
> > +static void ifcvf_free_irq(struct ifcvf_adapter *adapter, int queues)
> > +{
> > +	struct pci_dev *pdev = adapter->pdev;
> > -	devm_free_irq(&pdev->dev, vf->config_irq, vf);
> > +	ifcvf_free_vq_irq(adapter, queues);
> > +	ifcvf_free_config_irq(adapter);
> >   	ifcvf_free_irq_vectors(pdev);
> >   }
> > @@ -86,58 +142,172 @@ static int ifcvf_alloc_vectors(struct ifcvf_adapter *adapter)
> >   	return ret;
> >   }
> > -static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> > +static int ifcvf_request_per_vq_irq(struct ifcvf_adapter *adapter)
> >   {
> >   	struct pci_dev *pdev = adapter->pdev;
> >   	struct ifcvf_hw *vf = &adapter->vf;
> > -	int vector, nvectors, i, ret, irq;
> > -	u16 max_intr;
> > +	int i, vector, ret, irq;
> > -	nvectors = ifcvf_alloc_vectors(adapter);
> > -	if (!(nvectors > 0))
> > -		return nvectors;
> > +	for (i = 0; i < vf->nr_vring; i++) {
> > +		snprintf(vf->vring[i].msix_name, 256, "ifcvf[%s]-%d\n", pci_name(pdev), i);
> > +		vector = i;
> > +		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_vq_irq(adapter, i);
> > +		} else {
> > +			vf->vring[i].irq = irq;
> > +			ifcvf_set_vq_vector(vf, i, vector);
> > +		}
> > +	}
> > -	max_intr = vf->nr_vring + 1;
> > +	vf->vqs_shared_irq = -EINVAL;
> > +
> > +	return 0;
> > +}
> > +
> > +static int ifcvf_request_shared_vq_irq(struct ifcvf_adapter *adapter)
> > +{
> > +	struct pci_dev *pdev = adapter->pdev;
> > +	struct ifcvf_hw *vf = &adapter->vf;
> > +	int i, vector, ret, irq;
> > +
> > +	vector = 0;
> > +	/* reuse msix_name[256] space of vring0 to store shared vqs interrupt name */
> 
> 
> I think we can remove this comment since the code is straightforward.
> 
> 
> > +	snprintf(vf->vring[0].msix_name, 256, "ifcvf[%s]-vqs-shared-irq\n", pci_name(pdev));
> > +	irq = pci_irq_vector(pdev, vector);
> > +	ret = devm_request_irq(&pdev->dev, irq,
> > +			       ifcvf_vq_shared_intr_handler, 0,
> > +			       vf->vring[0].msix_name, vf);
> > +	if (ret) {
> > +		IFCVF_ERR(pdev, "Failed to request shared irq for vf\n");
> > +
> > +		return ret;
> > +	}
> > +
> > +	vf->vqs_shared_irq = irq;
> > +	for (i = 0; i < vf->nr_vring; i++) {
> > +		vf->vring[i].irq = -EINVAL;
> > +		ifcvf_set_vq_vector(vf, i, vector);
> > +	}
> > +
> > +	return 0;
> > +
> > +}
> > +
> > +static int ifcvf_request_dev_shared_irq(struct ifcvf_adapter *adapter)
> > +{
> > +	struct pci_dev *pdev = adapter->pdev;
> > +	struct ifcvf_hw *vf = &adapter->vf;
> > +	int i, vector, ret, irq;
> > +
> > +	vector = 0;
> > +	/* reuse msix_name[256] space of vring0 to store shared device interrupt name */
> > +	snprintf(vf->vring[0].msix_name, 256, "ifcvf[%s]-dev-shared-irq\n", pci_name(pdev));
> > +	irq = pci_irq_vector(pdev, vector);
> > +	ret = devm_request_irq(&pdev->dev, irq,
> > +			       ifcvf_dev_shared_intr_handler, 0,
> > +			       vf->vring[0].msix_name, vf);
> > +	if (ret) {
> > +		IFCVF_ERR(pdev, "Failed to request shared irq for vf\n");
> > -	ret = pci_alloc_irq_vectors(pdev, max_intr,
> > -				    max_intr, PCI_IRQ_MSIX);
> > -	if (ret < 0) {
> > -		IFCVF_ERR(pdev, "Failed to alloc IRQ vectors\n");
> >   		return ret;
> >   	}
> > +	vf->vqs_shared_irq = irq;
> > +	for (i = 0; i < vf->nr_vring; i++) {
> > +		vf->vring[i].irq = -EINVAL;
> > +		ifcvf_set_vq_vector(vf, i, vector);
> > +	}
> > +
> > +	vf->config_irq = irq;
> > +	ifcvf_set_config_vector(vf, vector);
> > +
> > +	return 0;
> > +
> > +}
> > +
> > +static int ifcvf_request_vq_irq(struct ifcvf_adapter *adapter)
> > +{
> > +	struct ifcvf_hw *vf = &adapter->vf;
> > +	int ret;
> > +
> > +	if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG)
> > +		ret = ifcvf_request_per_vq_irq(adapter);
> > +	else
> > +		ret = ifcvf_request_shared_vq_irq(adapter);
> > +
> > +	return ret;
> > +}
> > +
> > +static int ifcvf_request_config_irq(struct ifcvf_adapter *adapter)
> > +{
> > +	struct pci_dev *pdev = adapter->pdev;
> > +	struct ifcvf_hw *vf = &adapter->vf;
> > +	int config_vector, ret;
> > +
> > +	if (vf->msix_vector_status == MSIX_VECTOR_DEV_SHARED)
> > +		return 0;
> > +
> > +	if (vf->msix_vector_status == MSIX_VECTOR_PER_VQ_AND_CONFIG)
> > +		/* vector 0 ~ vf->nr_vring for vqs, num vf->nr_vring vector for config interrupt */
> > +		config_vector = vf->nr_vring;
> > +
> > +	if (vf->msix_vector_status ==  MSIX_VECTOR_SHARED_VQ_AND_CONFIG)
> > +		/* vector 0 for vqs and 1 for config interrupt */
> > +		config_vector = 1;
> > +
> >   	snprintf(vf->config_msix_name, 256, "ifcvf[%s]-config\n",
> >   		 pci_name(pdev));
> > -	vector = 0;
> > -	vf->config_irq = pci_irq_vector(pdev, vector);
> > +	vf->config_irq = pci_irq_vector(pdev, config_vector);
> >   	ret = devm_request_irq(&pdev->dev, vf->config_irq,
> >   			       ifcvf_config_changed, 0,
> >   			       vf->config_msix_name, vf);
> >   	if (ret) {
> >   		IFCVF_ERR(pdev, "Failed to request config irq\n");
> > +		ifcvf_free_vq_irq(adapter, vf->nr_vring);
> >   		return ret;
> >   	}
> > -	for (i = 0; i < vf->nr_vring; 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);
> > +	ifcvf_set_config_vector(vf, config_vector);
> > -			return ret;
> > -		}
> > +	return 0;
> > +}
> > +
> > +static int ifcvf_request_irq(struct ifcvf_adapter *adapter)
> > +{
> 
> 
> As replied above, I think having two modes should be sufficient and the code
> could be greatly simplified.
> 
> Thanks
> 

Well it is claimed there are platforms where we are short
on vectors. 3 versus 2 seems a 50% saving. You disagree?

> > +	struct ifcvf_hw *vf = &adapter->vf;
> > +	int nvectors, ret, max_intr;
> > -		vf->vring[i].irq = irq;
> > +	nvectors = ifcvf_alloc_vectors(adapter);
> > +	if (!(nvectors > 0))
> > +		return nvectors;
> > +
> > +	vf->msix_vector_status = MSIX_VECTOR_PER_VQ_AND_CONFIG;
> > +	max_intr = vf->nr_vring + 1;
> > +	if (nvectors < max_intr)
> > +		vf->msix_vector_status = MSIX_VECTOR_SHARED_VQ_AND_CONFIG;
> > +
> > +	if (nvectors == 1) {
> > +		vf->msix_vector_status = MSIX_VECTOR_DEV_SHARED;
> > +		ret = ifcvf_request_dev_shared_irq(adapter);
> > +
> > +		return ret;
> >   	}
> > +	ret = ifcvf_request_vq_irq(adapter);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = ifcvf_request_config_irq(adapter);
> > +
> > +	if (ret)
> > +		return ret;
> > +
> >   	return 0;
> >   }
> > @@ -441,7 +611,10 @@ static int ifcvf_vdpa_get_vq_irq(struct vdpa_device *vdpa_dev,
> >   {
> >   	struct ifcvf_hw *vf = vdpa_to_vf(vdpa_dev);
> > -	return vf->vring[qid].irq;
> > +	if (vf->vqs_shared_irq < 0)
> > +		return vf->vring[qid].irq;
> > +	else
> > +		return -EINVAL;
> >   }
> >   static struct vdpa_notification_area ifcvf_get_vq_notification(struct vdpa_device *vdpa_dev,