Added helper virtio_set_max_ring_num() to set the upper limit of ring num when creating a virtqueue.
Can be used to limit ring num before find_vqs() call. Or change ring num when re-enable reset queue. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/virtio/virtio_ring.c | 6 ++++++ include/linux/virtio.h | 1 + include/linux/virtio_config.h | 30 ++++++++++++++++++++++++++++++ 3 files changed, 37 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 1a123b5e5371..a77a82883e44 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -943,6 +943,9 @@ static struct virtqueue *vring_create_virtqueue_split( size_t queue_size_in_bytes; struct vring vring; + if (vdev->max_ring_num && num > vdev->max_ring_num) + num = vdev->max_ring_num; + /* We assume num is a power of 2. */ if (num & (num - 1)) { dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); @@ -1692,6 +1695,9 @@ static struct virtqueue *vring_create_virtqueue_packed( dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr; size_t ring_size_in_bytes, event_size_in_bytes; + if (vdev->max_ring_num && num > vdev->max_ring_num) + num = vdev->max_ring_num; + ring_size_in_bytes = num * sizeof(struct vring_packed_desc); ring = vring_alloc_queue(vdev, ring_size_in_bytes, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 1153b093c53d..45525beb2ec4 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -127,6 +127,7 @@ struct virtio_device { struct list_head vqs; u64 features; void *priv; + u16 max_ring_num; }; static inline struct virtio_device *dev_to_virtio(struct device *_dev) diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index cd7f7f44ce38..d7cb2d0341ee 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -200,6 +200,36 @@ static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev) return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM); } +/** + * virtio_set_max_ring_num - set max ring num + * @vdev: the device + * @num: max ring num. Zero clear the limit. + * + * When creating a virtqueue, use this value as the upper limit of ring num. + * + * Returns 0 on success or error status + */ +static inline +int virtio_set_max_ring_num(struct virtio_device *vdev, u16 num) +{ + if (!num) { + vdev->max_ring_num = num; + return 0; + } + + if (!virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) { + if (!is_power_of_2(num)) { + num = __rounddown_pow_of_two(num); + + if (!num) + return -EINVAL; + } + } + + vdev->max_ring_num = num; + return 0; +} + static inline struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, vq_callback_t *c, const char *n) -- 2.31.0 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
