[dpdk-dev] [PATCH v3 02/21] net/virtio: vring init for packed queues
Tiwei Bie
tiwei.bie at intel.com
Thu Apr 5 16:22:28 CEST 2018
On Thu, Apr 05, 2018 at 12:10:12PM +0200, Jens Freimann wrote:
> Add and initialize descriptor data structures.
>
> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
> ---
[...]
> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
> index 9e3c2a015..1bd7ba98e 100644
> --- a/drivers/net/virtio/virtio_ring.h
> +++ b/drivers/net/virtio/virtio_ring.h
> @@ -9,6 +9,7 @@
>
> #include <rte_common.h>
>
> +
There is no need to add this empty line.
> /* 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 +55,38 @@ 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;
> +};
> +
> +#define RING_EVENT_FLAGS_ENABLE 0x0
> +#define RING_EVENT_FLAGS_DISABLE 0x1
> +#define RING_EVENT_FLAGS_DESC 0x2
> +struct vring_packed_desc_event {
> + uint16_t desc_event_off_wrap;
> + uint16_t desc_event_flags;
> +};
> +
> struct vring {
> unsigned int num;
> - struct vring_desc *desc;
> - struct vring_avail *avail;
> - struct vring_used *used;
> + union {
> + struct vring_desc_packed *desc_packed;
> + struct vring_desc *desc;
> + };
> + union {
> + struct vring_avail *avail;
> + struct vring_packed_desc_event *driver_event;
> + };
> + union {
> + struct vring_used *used;
> + struct vring_packed_desc_event *device_event;
> + };
> };
>
> /* The standard layout for the ring is a continuous chunk of memory which
> @@ -95,10 +123,16 @@ struct vring {
> #define vring_avail_event(vr) (*(uint16_t *)&(vr)->used->ring[(vr)->num])
>
> static inline size_t
> -vring_size(unsigned int num, unsigned long align)
> +vring_size(struct virtio_hw *hw, unsigned int num, unsigned long align)
> {
> size_t size;
>
> + if (vtpci_packed_queue(hw)) {
> + size = num * sizeof(struct vring_desc_packed);
I think you need to add paddings based on the alignment.
> + size += 2 * sizeof(struct vring_packed_desc_event);
> + return size;
> + }
> +
> size = num * sizeof(struct vring_desc);
> size += sizeof(struct vring_avail) + (num * sizeof(uint16_t));
> size = RTE_ALIGN_CEIL(size, align);
> @@ -108,10 +142,19 @@ vring_size(unsigned int num, unsigned long align)
> }
>
> static inline void
> -vring_init(struct vring *vr, unsigned int num, uint8_t *p,
> +vring_init(struct virtio_hw *hw, struct vring *vr, unsigned int num, uint8_t *p,
> unsigned long align)
> {
> vr->num = num;
> + if (vtpci_packed_queue(hw)) {
> + vr->desc_packed = (struct vring_desc_packed *)p;
> + vr->driver_event = (struct vring_packed_desc_event *) (p +
> + num * sizeof(struct vring_desc_packed));
I think paddings are needed here.
> + vr->device_event = (struct vring_packed_desc_event *) (vr->driver_event +
> + sizeof(struct vring_packed_desc_event));
> + return;
> + }
> +
> vr->desc = (struct vring_desc *) p;
> vr->avail = (struct vring_avail *) (p +
> num * sizeof(struct vring_desc));
> diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
> index 14364f356..cc2e7c0f6 100644
> --- a/drivers/net/virtio/virtqueue.h
> +++ b/drivers/net/virtio/virtqueue.h
> @@ -245,6 +245,16 @@ struct virtio_tx_region {
> __attribute__((__aligned__(16)));
> };
>
> +static inline void
> +vring_desc_init_packed(struct vring *vr, int n)
> +{
> + int i;
> + for (i = 0; i < n; i++) {
> + struct vring_desc_packed *desc = &vr->desc_packed[i];
> + desc->index = i;
> + }
> +}
> +
> /* Chain all the descriptors in the ring with an END */
> static inline void
> vring_desc_init(struct vring_desc *dp, uint16_t n)
> --
> 2.14.3
>
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