Date:   Mon, 14 Feb 2022 09:27:30 -0500
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     Zhu Lingshan <lingshan.zhu@...ux.intel.com>
Cc:     Jason Wang <jasowang@...hat.com>,
        Zhu Lingshan <lingshan.zhu@...el.com>, netdev@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH V4 4/4] vDPA/ifcvf: implement shared IRQ feature

On Mon, Feb 14, 2022 at 06:01:56PM +0800, Zhu Lingshan wrote:
> 
> 
> On 2/14/2022 3:19 PM, 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 <lingshan.zhu@...el.com>
> > > ---
> > >   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?
> ifcvf driver sets NO_VECTOR when call hw_disable(). I am not sure whether I
> get it,
> Yes we can let the caller check a vq vector, however this may cause more
> than three levels brackets, may looks ugly.
> > 
> > 
> > > +
> > > +    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.
> IMHO we still need 2 and 3, because MSIX_VECTOR_SHARED_VQ_AND_CONFIG means
> there are at least 2 vectors,
> the vqs share one vector, config change has its own vector.
> MSIX_VECTOR_DEV_SHARED means three are only one vector, all vqs and config
> changes need to share this vector.
> > 
> > 
> > 
> > > +
> > >   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?
> for cacheline alignment.

maybe a separate patch then.

> > 
> > 
> > 
> > >       /* 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.
> OK, do you mean the comments? I can remove these comments.
> > 
> > 
> > >   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)
> > > +{
> > > +    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.
> > 
> > Always return IRQ_HANDLED will break the device who shares an irq with
> > IFCVF.
> as we discussed in another thread(spec inconsistency about ISR), ISR may
> only works for INTx for now,
> but VFs don't have INTx, and a VF may not share its vectors with other
> devices, so I guess it can work
> and may be our best try for now.
> > 
> > 
> > > +    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.
> sure
> > 
> > 
> > > + 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.
> Do you mean if we don't get enough vectors, just use only one vector for the
> vqs and config changes? I guess this
> only works if ISR work for MSIX as we expects, or we may waste some time in
> the device config space.
> 
> Thanks,
> Zhu Lingshan
> > 
> > Thanks
> > 
> > 
> > > +    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,
> > 
> > _______________________________________________
> > Virtualization mailing list
> > Virtualization@...ts.linux-foundation.org
> > https://lists.linuxfoundation.org/mailman/listinfo/virtualization

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