Date:   Tue, 15 Feb 2022 10:18:43 +0800
From:   "Zhu, Lingshan" <lingshan.zhu@...el.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>,
        Zhu Lingshan <lingshan.zhu@...ux.intel.com>
Cc:     Jason Wang <jasowang@...hat.com>, netdev@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH V4 4/4] vDPA/ifcvf: implement shared IRQ feature



On 2/14/2022 10:27 PM, Michael S. Tsirkin wrote:
> 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.
Sure

Thanks!
>
>>>
>>>
>>>>        /* 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,
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