On Mon, Feb 14, 2022 at 4:14 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> This patch implements virtio pci support for QUEUE RESET.
>
> Performing reset on a queue is divided into these steps:
>
> 1. reset_vq: reset one vq
> 2. recycle the buffer from vq by virtqueue_detach_unused_buf()
> 3. release the ring of the vq by vring_release_virtqueue()
> 4. enable_reset_vq: re-enable the reset queue
>
> This patch implements reset_vq, enable_reset_vq in the pci scenario.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_pci_common.c | 8 ++--
> drivers/virtio/virtio_pci_modern.c | 60 ++++++++++++++++++++++++++++++
> 2 files changed, 65 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index 5a4f750a0b97..9ea319b1d404 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -255,9 +255,11 @@ static void vp_del_vq(struct virtqueue *vq)
> struct virtio_pci_vq_info *info = vp_dev->vqs[vq->index];
> unsigned long flags;
>
> - spin_lock_irqsave(&vp_dev->lock, flags);
> - list_del(&info->node);
> - spin_unlock_irqrestore(&vp_dev->lock, flags);
> + if (!vq->reset) {
> + spin_lock_irqsave(&vp_dev->lock, flags);
> + list_del(&info->node);
> + spin_unlock_irqrestore(&vp_dev->lock, flags);
> + }
>
> vp_dev->del_vq(info);
> kfree(info);
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index bed3e9b84272..7d28f4c36fc2 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -34,6 +34,9 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features)
> if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
> pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
> __virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
> +
> + if (features & BIT_ULL(VIRTIO_F_RING_RESET))
> + __virtio_set_bit(vdev, VIRTIO_F_RING_RESET);
> }
>
> /* virtio config->finalize_features() implementation */
> @@ -176,6 +179,59 @@ static void vp_reset(struct virtio_device *vdev)
> vp_disable_cbs(vdev);
> }
>
> +static int vp_modern_reset_vq(struct virtqueue *vq)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> + struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> + struct virtio_pci_vq_info *info;
> + unsigned long flags;
> +
> + if (!virtio_has_feature(vq->vdev, VIRTIO_F_RING_RESET))
> + return -ENOENT;
> +
> + vp_modern_set_queue_reset(mdev, vq->index);
> +
> + info = vp_dev->vqs[vq->index];
> +
Any reason that we don't need to disable irq here as the previous versions did?
> + /* delete vq from irq handler */
> + spin_lock_irqsave(&vp_dev->lock, flags);
> + list_del(&info->node);
> + spin_unlock_irqrestore(&vp_dev->lock, flags);
> +
> + INIT_LIST_HEAD(&info->node);
> +
> + vq->reset = VIRTQUEUE_RESET_STAGE_DEVICE;
> +
> + return 0;
> +}
> +
> +static int vp_modern_enable_reset_vq(struct virtqueue *vq)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> + struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> + struct virtio_pci_vq_info *info;
> + struct virtqueue *_vq;
> +
> + if (vq->reset != VIRTQUEUE_RESET_STAGE_RELEASE)
> + return -EBUSY;
> +
> + /* check queue reset status */
> + if (vp_modern_get_queue_reset(mdev, vq->index) != 1)
> + return -EBUSY;
> +
> + info = vp_dev->vqs[vq->index];
> + _vq = vp_setup_vq(vq->vdev, vq->index, NULL, NULL, NULL,
> + info->msix_vector);
So we only care about moden devices, this means using vp_setup_vq()
with NULL seems tricky.
As replied in another thread, I would simply ask the caller to call
the vring reallocation helper. See the reply for patch 17.
Thanks
> + if (IS_ERR(_vq)) {
> + vq->reset = VIRTQUEUE_RESET_STAGE_RELEASE;
> + return PTR_ERR(_vq);
> + }
> +
> + vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true);
> +
> + return 0;
> +}
> +
> static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> {
> return vp_modern_config_vector(&vp_dev->mdev, vector);
> @@ -397,6 +453,8 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
> .set_vq_affinity = vp_set_vq_affinity,
> .get_vq_affinity = vp_get_vq_affinity,
> .get_shm_region = vp_get_shm_region,
> + .reset_vq = vp_modern_reset_vq,
> + .enable_reset_vq = vp_modern_enable_reset_vq,
> };
>
> static const struct virtio_config_ops virtio_pci_config_ops = {
> @@ -415,6 +473,8 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
> .set_vq_affinity = vp_set_vq_affinity,
> .get_vq_affinity = vp_get_vq_affinity,
> .get_shm_region = vp_get_shm_region,
> + .reset_vq = vp_modern_reset_vq,
> + .enable_reset_vq = vp_modern_enable_reset_vq,
> };
>
> /* the PCI probing function */
> --
> 2.31.0
>
