Re: [PATCH v7 08/10] virtio-pci: decouple virtqueue from kvm_virtio_pci_vector_use

[Jason Wang]

在 2021/6/2 上午11:47, Cindy Lu 写道:
> inorder


s/inorder/In order/


> to support configure interrupt, we need to decouple
> virtqueue from vector use and vector release function
> this patch introduce vector_release_one and vector_use_one
> to support one vector.
>
> Signed-off-by: Cindy Lu <lulu@redhat.com>


I think we need to reorder the patches to let such decoupling comes 
first in this series.


> ---
>   hw/virtio/virtio-pci.c | 122 ++++++++++++++++++++---------------------
>   1 file changed, 61 insertions(+), 61 deletions(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 6a4ef413a4..f863c89de6 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -666,7 +666,6 @@ static uint32_t virtio_read_config(PCIDevice *pci_dev,
>   }
>   
>   static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
> -                                        unsigned int queue_no,
>                                           unsigned int vector)
>   {
>       VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
> @@ -710,85 +709,86 @@ static void kvm_virtio_pci_irqfd_release(VirtIOPCIProxy 
> *proxy,
>       ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n, irqfd->virq);
>       assert(ret == 0);
>   }
> -
> -static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
> +static int virtio_pci_get_notifier(VirtIOPCIProxy *proxy, int queue_no,
> +                                      EventNotifier **n, unsigned int *vector)
>   {
>       PCIDevice *dev = &proxy->pci_dev;
>       VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> -    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> -    unsigned int vector;
> -    int ret, queue_no;
>       VirtQueue *vq;
> -    EventNotifier *n;
> -    for (queue_no = 0; queue_no < nvqs; queue_no++) {
> +
> +    if (queue_no == VIRTIO_CONFIG_IRQ_IDX) {
> +        return -1;
> +    } else {
>           if (!virtio_queue_get_num(vdev, queue_no)) {
> -            break;
> -        }
> -        vector = virtio_queue_vector(vdev, queue_no);
> -        if (vector >= msix_nr_vectors_allocated(dev)) {
> -            continue;
> -        }
> -        ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector);
> -        if (ret < 0) {
> -            goto undo;
> -        }
> -        /* If guest supports masking, set up irqfd now.
> -         * Otherwise, delay until unmasked in the frontend.
> -         */
> -        if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> -            vq = virtio_get_queue(vdev, queue_no);
> -            n = virtio_queue_get_guest_notifier(vq);
> -            ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
> -            if (ret < 0) {
> -                kvm_virtio_pci_vq_vector_release(proxy, vector);
> -                goto undo;
> -            }
> +            return -1;
>           }
> +        *vector = virtio_queue_vector(vdev, queue_no);
> +        vq = virtio_get_queue(vdev, queue_no);
> +        *n = virtio_queue_get_guest_notifier(vq);
> +    }
> +    if (*vector >= msix_nr_vectors_allocated(dev)) {
> +        return -1;
>       }
>       return 0;
> +}
>   
> +static int kvm_virtio_pci_vector_use_one(VirtIOPCIProxy *proxy, int queue_no)
> +{


To ease the reviewer, let's separate this patch into two.

1) factoring out the core logic
2) decouple the vq

Thanks


> +    unsigned int vector;
> +    int ret;
> +    EventNotifier *n;
> +    ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +    ret = kvm_virtio_pci_vq_vector_use(proxy, vector);
> +    if (ret < 0) {
> +        goto undo;
> +    }
> +    ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
> +    if (ret < 0) {
> +        goto undo;
> +    }
> +    return 0;
>   undo:
> -    while (--queue_no >= 0) {
> -        vector = virtio_queue_vector(vdev, queue_no);
> -        if (vector >= msix_nr_vectors_allocated(dev)) {
> -            continue;
> -        }
> -        if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> -            vq = virtio_get_queue(vdev, queue_no);
> -            n = virtio_queue_get_guest_notifier(vq);
> -            kvm_virtio_pci_irqfd_release(proxy, n, vector);
> -        }
> -        kvm_virtio_pci_vq_vector_release(proxy, vector);
> +    kvm_virtio_pci_irqfd_release(proxy, n, vector);
> +    return ret;
> +}
> +static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
> +{
> +    int queue_no;
> +    int ret = 0;
> +    for (queue_no = 0; queue_no < nvqs; queue_no++) {
> +        ret = kvm_virtio_pci_vector_use_one(proxy, queue_no);
>       }
>       return ret;
>   }
>   
> -static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
> +
> +static void kvm_virtio_pci_vector_release_one(VirtIOPCIProxy *proxy,
> +                        int queue_no)
>   {
> -    PCIDevice *dev = &proxy->pci_dev;
>       VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
>       unsigned int vector;
> -    int queue_no;
> -    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> -    VirtQueue *vq;
>       EventNotifier *n;
> +    int ret;
> +    VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
> +    ret = virtio_pci_get_notifier(proxy, queue_no, &n, &vector);
> +    if (ret < 0) {
> +        return;
> +    }
> +
> +    if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> +        kvm_virtio_pci_irqfd_release(proxy, n, vector);
> +    }
> +    kvm_virtio_pci_vq_vector_release(proxy, vector);
> +}
> +static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
> +{
> +    int queue_no;
> +
>       for (queue_no = 0; queue_no < nvqs; queue_no++) {
> -        if (!virtio_queue_get_num(vdev, queue_no)) {
> -            break;
> -        }
> -        vector = virtio_queue_vector(vdev, queue_no);
> -        if (vector >= msix_nr_vectors_allocated(dev)) {
> -            continue;
> -        }
> -        /* If guest supports masking, clean up irqfd now.
> -         * Otherwise, it was cleaned when masked in the frontend.
> -         */
> -        if (vdev->use_guest_notifier_mask && k->guest_notifier_mask) {
> -            vq = virtio_get_queue(vdev, queue_no);
> -            n = virtio_queue_get_guest_notifier(vq);
> -            kvm_virtio_pci_irqfd_release(proxy, n, vector);
> -        }
> -        kvm_virtio_pci_vq_vector_release(proxy, vector);
> +        kvm_virtio_pci_vector_release_one(proxy, queue_no);
>       }
>   }
>