On Sun, Oct 29, 2023 at 05:59:45PM +0200, Yishai Hadas wrote:
> From: Feng Liu <feliu@xxxxxxxxxx>
>
> Introduce support for the admin virtqueue. By negotiating
> VIRTIO_F_ADMIN_VQ feature, driver detects capability and creates one
> administration virtqueue. Administration virtqueue implementation in
> virtio pci generic layer, enables multiple types of upper layer
> drivers such as vfio, net, blk to utilize it.
>
> Signed-off-by: Feng Liu <feliu@xxxxxxxxxx>
> Reviewed-by: Parav Pandit <parav@xxxxxxxxxx>
> Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
> Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxx>
> ---
> drivers/virtio/virtio.c | 37 ++++++++++++++--
> drivers/virtio/virtio_pci_common.c | 3 ++
> drivers/virtio/virtio_pci_common.h | 15 ++++++-
> drivers/virtio/virtio_pci_modern.c | 61 +++++++++++++++++++++++++-
> drivers/virtio/virtio_pci_modern_dev.c | 18 ++++++++
> include/linux/virtio_config.h | 4 ++
> include/linux/virtio_pci_modern.h | 5 +++
> 7 files changed, 137 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> index 3893dc29eb26..f4080692b351 100644
> --- a/drivers/virtio/virtio.c
> +++ b/drivers/virtio/virtio.c
> @@ -302,9 +302,15 @@ static int virtio_dev_probe(struct device *_d)
> if (err)
> goto err;
>
> + if (dev->config->create_avq) {
> + err = dev->config->create_avq(dev);
> + if (err)
> + goto err;
> + }
> +
> err = drv->probe(dev);
> if (err)
> - goto err;
> + goto err_probe;
>
> /* If probe didn't do it, mark device DRIVER_OK ourselves. */
> if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
Hmm I am not all that happy that we are just creating avq
unconditionally.
Can't we do it on demand to avoid wasting resources if
no one uses it?
> @@ -316,6 +322,10 @@ static int virtio_dev_probe(struct device *_d)
> virtio_config_enable(dev);
>
> return 0;
> +
> +err_probe:
> + if (dev->config->destroy_avq)
> + dev->config->destroy_avq(dev);
> err:
> virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> return err;
> @@ -331,6 +341,9 @@ static void virtio_dev_remove(struct device *_d)
>
> drv->remove(dev);
>
> + if (dev->config->destroy_avq)
> + dev->config->destroy_avq(dev);
> +
> /* Driver should have reset device. */
> WARN_ON_ONCE(dev->config->get_status(dev));
>
> @@ -489,13 +502,20 @@ EXPORT_SYMBOL_GPL(unregister_virtio_device);
> int virtio_device_freeze(struct virtio_device *dev)
> {
> struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> + int ret;
>
> virtio_config_disable(dev);
>
> dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
>
> - if (drv && drv->freeze)
> - return drv->freeze(dev);
> + if (drv && drv->freeze) {
> + ret = drv->freeze(dev);
> + if (ret)
> + return ret;
> + }
> +
> + if (dev->config->destroy_avq)
> + dev->config->destroy_avq(dev);
>
> return 0;
> }
> @@ -532,10 +552,16 @@ int virtio_device_restore(struct virtio_device *dev)
> if (ret)
> goto err;
>
> + if (dev->config->create_avq) {
> + ret = dev->config->create_avq(dev);
> + if (ret)
> + goto err;
> + }
> +
> if (drv->restore) {
> ret = drv->restore(dev);
> if (ret)
> - goto err;
> + goto err_restore;
> }
>
> /* If restore didn't do it, mark device DRIVER_OK ourselves. */
> @@ -546,6 +572,9 @@ int virtio_device_restore(struct virtio_device *dev)
>
> return 0;
>
> +err_restore:
> + if (dev->config->destroy_avq)
> + dev->config->destroy_avq(dev);
> err:
> virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> return ret;
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index c2524a7207cf..6b4766d5abe6 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -236,6 +236,9 @@ void vp_del_vqs(struct virtio_device *vdev)
> int i;
>
> list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
> + if (vp_dev->is_avq(vdev, vq->index))
> + continue;
> +
> if (vp_dev->per_vq_vectors) {
> int v = vp_dev->vqs[vq->index]->msix_vector;
>
> diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
> index 4b773bd7c58c..e03af0966a4b 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -41,6 +41,14 @@ struct virtio_pci_vq_info {
> unsigned int msix_vector;
> };
>
> +struct virtio_pci_admin_vq {
> + /* Virtqueue info associated with this admin queue. */
> + struct virtio_pci_vq_info info;
> + /* Name of the admin queue: avq.$index. */
> + char name[10];
> + u16 vq_index;
> +};
> +
> /* Our device structure */
> struct virtio_pci_device {
> struct virtio_device vdev;
> @@ -58,9 +66,13 @@ struct virtio_pci_device {
> spinlock_t lock;
> struct list_head virtqueues;
>
> - /* array of all queues for house-keeping */
> + /* Array of all virtqueues reported in the
> + * PCI common config num_queues field
> + */
> struct virtio_pci_vq_info **vqs;
>
> + struct virtio_pci_admin_vq admin_vq;
> +
> /* MSI-X support */
> int msix_enabled;
> int intx_enabled;
> @@ -86,6 +98,7 @@ struct virtio_pci_device {
> void (*del_vq)(struct virtio_pci_vq_info *info);
>
> u16 (*config_vector)(struct virtio_pci_device *vp_dev, u16 vector);
> + bool (*is_avq)(struct virtio_device *vdev, unsigned int index);
> };
>
> /* Constants for MSI-X */
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index d6bb68ba84e5..01c5ba346471 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -26,6 +26,16 @@ static u64 vp_get_features(struct virtio_device *vdev)
> return vp_modern_get_features(&vp_dev->mdev);
> }
>
> +static bool vp_is_avq(struct virtio_device *vdev, unsigned int index)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +
> + if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
> + return false;
> +
> + return index == vp_dev->admin_vq.vq_index;
> +}
> +
> static void vp_transport_features(struct virtio_device *vdev, u64 features)
> {
> struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> @@ -37,6 +47,9 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features)
>
> if (features & BIT_ULL(VIRTIO_F_RING_RESET))
> __virtio_set_bit(vdev, VIRTIO_F_RING_RESET);
> +
> + if (features & BIT_ULL(VIRTIO_F_ADMIN_VQ))
> + __virtio_set_bit(vdev, VIRTIO_F_ADMIN_VQ);
> }
>
> /* virtio config->finalize_features() implementation */
> @@ -317,7 +330,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> else
> notify = vp_notify;
>
> - if (index >= vp_modern_get_num_queues(mdev))
> + if (index >= vp_modern_get_num_queues(mdev) &&
> + !vp_is_avq(&vp_dev->vdev, index))
> return ERR_PTR(-EINVAL);
>
> /* Check if queue is either not available or already active. */
> @@ -491,6 +505,46 @@ static bool vp_get_shm_region(struct virtio_device *vdev,
> return true;
> }
>
> +static int vp_modern_create_avq(struct virtio_device *vdev)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> + struct virtio_pci_admin_vq *avq;
> + struct virtqueue *vq;
> + u16 admin_q_num;
> +
> + if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
> + return 0;
> +
> + admin_q_num = vp_modern_avq_num(&vp_dev->mdev);
> + if (!admin_q_num)
> + return -EINVAL;
We really just need 1 entry ATM. Limit to that?
> +
> + avq = &vp_dev->admin_vq;
> + avq->vq_index = vp_modern_avq_index(&vp_dev->mdev);
> + sprintf(avq->name, "avq.%u", avq->vq_index);
> + vq = vp_dev->setup_vq(vp_dev, &vp_dev->admin_vq.info, avq->vq_index, NULL,
> + avq->name, NULL, VIRTIO_MSI_NO_VECTOR);
> + if (IS_ERR(vq)) {
> + dev_err(&vdev->dev, "failed to setup admin virtqueue, err=%ld",
> + PTR_ERR(vq));
> + return PTR_ERR(vq);
> + }
> +
> + vp_dev->admin_vq.info.vq = vq;
> + vp_modern_set_queue_enable(&vp_dev->mdev, avq->info.vq->index, true);
> + return 0;
> +}
> +
> +static void vp_modern_destroy_avq(struct virtio_device *vdev)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +
> + if (!virtio_has_feature(vdev, VIRTIO_F_ADMIN_VQ))
> + return;
> +
> + vp_dev->del_vq(&vp_dev->admin_vq.info);
> +}
> +
> static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
> .get = NULL,
> .set = NULL,
> @@ -509,6 +563,8 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
> .get_shm_region = vp_get_shm_region,
> .disable_vq_and_reset = vp_modern_disable_vq_and_reset,
> .enable_vq_after_reset = vp_modern_enable_vq_after_reset,
> + .create_avq = vp_modern_create_avq,
> + .destroy_avq = vp_modern_destroy_avq,
> };
>
> static const struct virtio_config_ops virtio_pci_config_ops = {
> @@ -529,6 +585,8 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
> .get_shm_region = vp_get_shm_region,
> .disable_vq_and_reset = vp_modern_disable_vq_and_reset,
> .enable_vq_after_reset = vp_modern_enable_vq_after_reset,
> + .create_avq = vp_modern_create_avq,
> + .destroy_avq = vp_modern_destroy_avq,
> };
>
> /* the PCI probing function */
> @@ -552,6 +610,7 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
> vp_dev->config_vector = vp_config_vector;
> vp_dev->setup_vq = setup_vq;
> vp_dev->del_vq = del_vq;
> + vp_dev->is_avq = vp_is_avq;
> vp_dev->isr = mdev->isr;
> vp_dev->vdev.id = mdev->id;
>
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index 9cb601e16688..4aab1727d121 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -714,6 +714,24 @@ void __iomem *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
> }
> EXPORT_SYMBOL_GPL(vp_modern_map_vq_notify);
>
> +u16 vp_modern_avq_num(struct virtio_pci_modern_device *mdev)
> +{
> + struct virtio_pci_modern_common_cfg __iomem *cfg;
> +
> + cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
> + return vp_ioread16(&cfg->admin_queue_num);
> +}
> +EXPORT_SYMBOL_GPL(vp_modern_avq_num);
> +
> +u16 vp_modern_avq_index(struct virtio_pci_modern_device *mdev)
> +{
> + struct virtio_pci_modern_common_cfg __iomem *cfg;
> +
> + cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
> + return vp_ioread16(&cfg->admin_queue_index);
> +}
> +EXPORT_SYMBOL_GPL(vp_modern_avq_index);
> +
> MODULE_VERSION("0.1");
> MODULE_DESCRIPTION("Modern Virtio PCI Device");
> MODULE_AUTHOR("Jason Wang <jasowang@xxxxxxxxxx>");
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index 2b3438de2c4d..da9b271b54db 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -93,6 +93,8 @@ typedef void vq_callback_t(struct virtqueue *);
> * Returns 0 on success or error status
> * If disable_vq_and_reset is set, then enable_vq_after_reset must also be
> * set.
> + * @create_avq: create admin virtqueue resource.
> + * @destroy_avq: destroy admin virtqueue resource.
> */
> struct virtio_config_ops {
> void (*get)(struct virtio_device *vdev, unsigned offset,
> @@ -120,6 +122,8 @@ struct virtio_config_ops {
> struct virtio_shm_region *region, u8 id);
> int (*disable_vq_and_reset)(struct virtqueue *vq);
> int (*enable_vq_after_reset)(struct virtqueue *vq);
> + int (*create_avq)(struct virtio_device *vdev);
> + void (*destroy_avq)(struct virtio_device *vdev);
> };
>
> /* If driver didn't advertise the feature, it will never appear. */
> diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> index 067ac1d789bc..0f8737c9ae7d 100644
> --- a/include/linux/virtio_pci_modern.h
> +++ b/include/linux/virtio_pci_modern.h
> @@ -10,6 +10,9 @@ struct virtio_pci_modern_common_cfg {
>
> __le16 queue_notify_data; /* read-write */
> __le16 queue_reset; /* read-write */
> +
> + __le16 admin_queue_index; /* read-only */
> + __le16 admin_queue_num; /* read-only */
> };
>
> struct virtio_pci_modern_device {
> @@ -121,4 +124,6 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev);
> void vp_modern_remove(struct virtio_pci_modern_device *mdev);
> int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index);
> void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index);
> +u16 vp_modern_avq_num(struct virtio_pci_modern_device *mdev);
> +u16 vp_modern_avq_index(struct virtio_pci_modern_device *mdev);
> #endif
> --
> 2.27.0
