Re: [PATCH 01/17] net/virtio: vring init for packed queues

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 03/16/2018 04:21 PM, Jens Freimann wrote:
> Add and initialize descriptor data structures.
> 
> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
> ---
>   drivers/net/virtio/virtio_ethdev.c | 22 ++++++++++++----------
>   drivers/net/virtio/virtio_pci.h    |  8 ++++++++
>   drivers/net/virtio/virtio_ring.h   | 25 +++++++++++++++++++++++--
>   drivers/net/virtio/virtqueue.h     | 10 ++++++++++
>   4 files changed, 53 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index 884f74a..ce4f53d 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -299,19 +299,21 @@ struct rte_virtio_xstats_name_off {
>   
>   	PMD_INIT_FUNC_TRACE();
>   
> -	/*
> -	 * Reinitialise since virtio port might have been stopped and restarted
> -	 */

Are you sure the comment has to be removed?

>   	memset(ring_mem, 0, vq->vq_ring_size);
> -	vring_init(vr, size, ring_mem, VIRTIO_PCI_VRING_ALIGN);
> -	vq->vq_used_cons_idx = 0;
> -	vq->vq_desc_head_idx = 0;
> -	vq->vq_avail_idx = 0;
> -	vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
> +	vring_init(vq->hw, vr, size, ring_mem, VIRTIO_PCI_VRING_ALIGN);
> +
>   	vq->vq_free_cnt = vq->vq_nentries;
>   	memset(vq->vq_descx, 0, sizeof(struct vq_desc_extra) * vq->vq_nentries);
> +	vq->vq_used_cons_idx = 0;
> +	vq->vq_avail_idx     = 0;
> +	if (vtpci_packed_queue(vq->hw)) {
> +		vring_desc_init_packed(vr, size);
> +	} else {
> +		vq->vq_desc_head_idx = 0;
> +		vq->vq_desc_tail_idx = (uint16_t)(vq->vq_nentries - 1);
>   
> -	vring_desc_init(vr->desc, size);
> +		vring_desc_init(vr->desc, size);
> +	}
>   
>   	/*
>   	 * Disable device(host) interrupting guest
> @@ -386,7 +388,7 @@ struct rte_virtio_xstats_name_off {
>   	/*
>   	 * Reserve a memzone for vring elements
>   	 */
> -	size = vring_size(vq_size, VIRTIO_PCI_VRING_ALIGN);
> +	size = vring_size(hw, vq_size, VIRTIO_PCI_VRING_ALIGN);
>   	vq->vq_ring_size = RTE_ALIGN_CEIL(size, VIRTIO_PCI_VRING_ALIGN);
>   	PMD_INIT_LOG(DEBUG, "vring_size: %d, rounded_vring_size: %d",
>   		     size, vq->vq_ring_size);
> diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
> index a28ba83..528fb46 100644
> --- a/drivers/net/virtio/virtio_pci.h
> +++ b/drivers/net/virtio/virtio_pci.h
> @@ -112,6 +112,8 @@
>   
>   #define VIRTIO_F_VERSION_1		32
>   #define VIRTIO_F_IOMMU_PLATFORM	33
> +#define VIRTIO_F_RING_PACKED		34
> +#define VIRTIO_F_IN_ORDER		35
>   
>   /*
>    * Some VirtIO feature bits (currently bits 28 through 31) are
> @@ -304,6 +306,12 @@ enum virtio_msix_status {
>   	return (hw->guest_features & (1ULL << bit)) != 0;
>   }
>   
> +static inline int
> +vtpci_packed_queue(struct virtio_hw *hw)
> +{
> +	return vtpci_with_feature(hw, VIRTIO_F_RING_PACKED);
> +}
> +
>   /*
>    * Function declaration from virtio_pci.c
>    */
> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
> index 9e3c2a0..fc45e34 100644
> --- a/drivers/net/virtio/virtio_ring.h
> +++ b/drivers/net/virtio/virtio_ring.h
> @@ -9,6 +9,7 @@
>   
>   #include <rte_common.h>
>   
> +
>   /* This marks a buffer as continuing via the next field. */
>   #define VRING_DESC_F_NEXT       1
>   /* This marks a buffer as write-only (otherwise read-only). */
> @@ -54,11 +55,23 @@ struct vring_used {
>   	struct vring_used_elem ring[0];
>   };
>   
> +/* For support of packed virtqueues in Virtio 1.1 the format of descriptors
> + * looks like this.
> + */
> +struct vring_desc_packed {
> +	uint64_t addr;
> +	uint32_t len;
> +	uint16_t index;
> +	uint16_t flags;
> +};
> +
> +
Trailing new line.
>   struct vring {
>   	unsigned int num;
>   	struct vring_desc  *desc;
>   	struct vring_avail *avail;
>   	struct vring_used  *used;
> +	struct vring_desc_packed *desc_packed;
>   };
...