Message-ID: <CACGkMEsW_yaVSW7dBECT1LOUVKapJvcBZeaDRtuwmeZHysfwSA@mail.gmail.com>
Date:   Tue, 15 Feb 2022 11:03:27 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     "Zhu, Lingshan" <lingshan.zhu@...el.com>
Cc:     "Michael S. Tsirkin" <mst@...hat.com>,
        Zhu Lingshan <lingshan.zhu@...ux.intel.com>,
        netdev <netdev@...r.kernel.org>,
        virtualization <virtualization@...ts.linux-foundation.org>
Subject: Re: [PATCH V4 4/4] vDPA/ifcvf: implement shared IRQ feature

On Tue, Feb 15, 2022 at 10:18 AM Zhu, Lingshan <lingshan.zhu@...el.com> wrote:
>
>
>
> 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,

I meant you invent the ifcvf_set_vq_vector() you'd better use that in
hw_disable() as well.

> >> Yes we can let the caller check a vq vector, however this may cause more
> >> than three levels brackets, may looks ugly.

I don't understand here, this is how virito_pci did:

/*
 * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
 * @mdev: the modern virtio-pci device
 * @index: queue index
 * @vector: the config vector
 *
 * Returns the config vector read from the device
 */
u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
                           u16 index, u16 vector)
{
        struct virtio_pci_common_cfg __iomem *cfg = mdev->common;

        vp_iowrite16(index, &cfg->queue_select);
        vp_iowrite16(vector, &cfg->queue_msix_vector);
        /* Flush the write out to device */
        return vp_ioread16(&cfg->queue_msix_vector);
}
EXPORT_SYMBOL_GPL(vp_modern_queue_vector);

> >>>
> >>>> +
> >>>> +    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.

I want to know the value of having a dedicated vector for config?

> >> 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.

Yes.

> >>>
> >>>>    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.

Right, I thought you're using shared irq but actually not.

> >>>
> >>>> +    if (isr & VIRTIO_PCI_ISR_CONFIG)
> >>>> +        ifcvf_config_changed(irq, arg);

I wonder how ISR works in IFCVF, if ISR doesn't work for MSI, we need
to remove the check of isr otherwise we will break config interrupt?

> >>>> +
> >>>> +    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.

Ok, I think I got you here. It's better to document this in the change log.

Thanks

> >>
> >> 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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