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Message-ID: <0908a9f6-562d-fab5-39c3-2f0125acc80e@redhat.com>
Date: Mon, 7 Feb 2022 14:57:13 +0800
From: Jason Wang <jasowang@...hat.com>
To: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org
Cc: "Michael S. Tsirkin" <mst@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Jesper Dangaard Brouer <hawk@...nel.org>,
John Fastabend <john.fastabend@...il.com>, bpf@...r.kernel.org
Subject: Re: [PATCH v3 13/17] virtio_pci: queue_reset: support
VIRTIO_F_RING_RESET
在 2022/1/26 下午3:35, Xuan Zhuo 写道:
> This patch implements virtio pci support for QUEUE RESET.
>
> Performing reset on a queue is divided into two steps:
>
> 1. reset_vq: reset one vq
> 2. enable_reset_vq: re-enable the reset queue
>
> In the first step, these tasks will be completed:
> 1. notify the hardware queue to reset
> 2. recycle the buffer from vq
> 3. release the ring of the vq
>
> The process of enable reset vq:
> vp_modern_enable_reset_vq()
> vp_enable_reset_vq()
> __vp_setup_vq()
> setup_vq()
> vring_setup_virtqueue()
>
> In this process, we added two parameters, vq and num, and finally passed
> them to vring_setup_virtqueue(). And reuse the original info and vq.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
> ---
> drivers/virtio/virtio_pci_common.c | 36 +++++++----
> drivers/virtio/virtio_pci_common.h | 5 ++
> drivers/virtio/virtio_pci_modern.c | 100 +++++++++++++++++++++++++++++
> 3 files changed, 128 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index c02936d29a31..ad21638fbf66 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -205,23 +205,28 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
> return err;
> }
>
> -static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
> - void (*callback)(struct virtqueue *vq),
> - const char *name,
> - bool ctx,
> - u16 msix_vec, u16 num)
> +struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
> + void (*callback)(struct virtqueue *vq),
> + const char *name,
> + bool ctx,
> + u16 msix_vec, u16 num)
> {
> struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> - struct virtio_pci_vq_info *info = kmalloc(sizeof *info, GFP_KERNEL);
> + struct virtio_pci_vq_info *info;
> struct virtqueue *vq;
> unsigned long flags;
>
> - /* fill out our structure that represents an active queue */
> - if (!info)
> - return ERR_PTR(-ENOMEM);
> + info = vp_dev->vqs[index];
> + if (!info) {
> + info = kzalloc(sizeof *info, GFP_KERNEL);
> +
> + /* fill out our structure that represents an active queue */
> + if (!info)
> + return ERR_PTR(-ENOMEM);
> + }
>
> vq = vp_dev->setup_vq(vp_dev, info, index, callback, name, ctx,
> - msix_vec, NULL, num);
> + msix_vec, info->vq, num);
> if (IS_ERR(vq))
> goto out_info;
>
> @@ -238,6 +243,9 @@ static struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
> return vq;
>
> out_info:
> + if (info->vq && info->vq->reset)
> + return vq;
> +
> kfree(info);
> return vq;
> }
> @@ -248,9 +256,11 @@ 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_common.h b/drivers/virtio/virtio_pci_common.h
> index 65db92245e41..c1d15f7c0be4 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -119,6 +119,11 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
> struct virtqueue *vqs[], vq_callback_t *callbacks[],
> const char * const names[], const bool *ctx,
> struct irq_affinity *desc);
> +struct virtqueue *vp_setup_vq(struct virtio_device *vdev, unsigned index,
> + void (*callback)(struct virtqueue *vq),
> + const char *name,
> + bool ctx,
> + u16 msix_vec, u16 num);
> const char *vp_bus_name(struct virtio_device *vdev);
>
> /* Setup the affinity for a virtqueue:
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 2ce58de549de..6789411169e4 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 +179,94 @@ static void vp_reset(struct virtio_device *vdev)
> vp_disable_cbs(vdev);
> }
>
> +static int vp_modern_reset_vq(struct virtio_reset_vq *param)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(param->vdev);
> + struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> + struct virtio_pci_vq_info *info;
> + u16 msix_vec, queue_index;
> + unsigned long flags;
> + void *buf;
> +
> + if (!virtio_has_feature(param->vdev, VIRTIO_F_RING_RESET))
> + return -ENOENT;
> +
> + queue_index = param->queue_index;
> +
> + vp_modern_set_queue_reset(mdev, queue_index);
> +
> + /* After write 1 to queue reset, the driver MUST wait for a read of
> + * queue reset to return 1.
> + */
> + while (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> + msleep(1);
Is this better to move this logic into vp_modern_set_queue_reset()?
> +
> + info = vp_dev->vqs[queue_index];
> + msix_vec = info->msix_vector;
> +
> + /* Disable VQ callback. */
> + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR)
> + disable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec));
How about the INTX case where irq is shared? I guess we need to disable
and enable the irq as well.
> +
> + while ((buf = virtqueue_detach_unused_buf(info->vq)) != NULL)
> + param->free_unused_cb(param, buf);
Any reason that we can't leave this logic to driver? (Or is there any
operations that must be done before the following operations?)
> +
> + /* delete vq */
> + spin_lock_irqsave(&vp_dev->lock, flags);
> + list_del(&info->node);
> + spin_unlock_irqrestore(&vp_dev->lock, flags);
> +
> + INIT_LIST_HEAD(&info->node);
> +
> + if (vp_dev->msix_enabled)
> + vp_modern_queue_vector(mdev, info->vq->index,
> + VIRTIO_MSI_NO_VECTOR);
I wonder if this is a must.
> +
> + if (!mdev->notify_base)
> + pci_iounmap(mdev->pci_dev,
> + (void __force __iomem *)info->vq->priv);
Is this a must? what happens if we simply don't do this?
> +
> + vring_reset_virtqueue(info->vq);
> +
> + return 0;
> +}
> +
> +static struct virtqueue *vp_modern_enable_reset_vq(struct virtio_reset_vq *param)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(param->vdev);
> + struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> + struct virtio_pci_vq_info *info;
> + u16 msix_vec, queue_index;
> + struct virtqueue *vq;
> +
> + if (!virtio_has_feature(param->vdev, VIRTIO_F_RING_RESET))
> + return ERR_PTR(-ENOENT);
> +
> + queue_index = param->queue_index;
> +
> + info = vp_dev->vqs[queue_index];
> +
> + if (!info->vq->reset)
> + return ERR_PTR(-EPERM);
> +
> + /* check queue reset status */
> + if (vp_modern_get_queue_reset(mdev, queue_index) != 1)
> + return ERR_PTR(-EBUSY);
> +
> + vq = vp_setup_vq(param->vdev, queue_index, param->callback, param->name,
> + param->ctx, info->msix_vector, param->ring_num);
> + if (IS_ERR(vq))
> + return vq;
> +
> + vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true);
> +
> + msix_vec = vp_dev->vqs[queue_index]->msix_vector;
> + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR)
> + enable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec));
How about the INT-X case?
Thanks
> +
> + return vq;
> +}
> +
> static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> {
> return vp_modern_config_vector(&vp_dev->mdev, vector);
> @@ -284,6 +375,11 @@ static void del_vq(struct virtio_pci_vq_info *info)
> struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
> struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
>
> + if (vq->reset) {
> + vring_del_virtqueue(vq);
> + return;
> + }
> +
> if (vp_dev->msix_enabled)
> vp_modern_queue_vector(mdev, vq->index,
> VIRTIO_MSI_NO_VECTOR);
> @@ -403,6 +499,8 @@ 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 = {
> @@ -421,6 +519,8 @@ 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 */
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