virtio 协议

liaocj 2024-07-23 15:20:11
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split ring

packed ring

wrap_counter

#define VIRTQ_DESC_F_AVAIL (1 << 7)
#define VIRTQ_DESC_F_USED (1 << 15)

avail buf
avail_wrap_counter 初始化为1
VIRTQ_DESC_F_AVAIL == avail_wrap_counter
VIRTQ_DESC_F_USED != avail_wrap_counter

used buf
used_wrap_counter 初始化为1
used = !!(flags & VRING_PACKED_DESC_F_USED);
avail = !!(flags & VRING_PACKED_DESC_F_AVAIL);
avail == used && used == vq->vq_packed.used_wrap_counter;

avail_wrap_counter == 1 -> a 1 u 0
avail_wrap_counter == 0 -> a 0 u 1

if (vq->used_wrap_counter) {
flags |= VRING_DESC_F_USED;
flags |= VRING_DESC_F_AVAIL;
} else {
flags &= ~VRING_DESC_F_USED;
flags &= ~VRING_DESC_F_AVAIL;
}

dpdk packed ring 初始化

digraph { fontname="Helvetica,Arial,sans-serif" //node [fontname="Helvetica,Arial,sans-serif"] //edge [fontname="Helvetica,Arial,sans-serif"] //rankdir="LR" node [fontsize=10, shape=record, height=0.25] edge [fontsize=10] virtio_init_vring -> vring_init_packed }

dpdk packed ring 收包逻辑

前端处理逻辑

digraph { fontname="Helvetica,Arial,sans-serif" //node [fontname="Helvetica,Arial,sans-serif"] //edge [fontname="Helvetica,Arial,sans-serif"] //rankdir="LR" node [fontsize=10, shape=record, height=0.25] edge [fontsize=10] virtio_recv_pkts_packed_vec -> virtio_recv_refill_packed_vec virtio_recv_pkts_packed -> virtqueue_enqueue_recv_refill_packed }
## 后端处理逻辑
digraph { fontname="Helvetica,Arial,sans-serif" //node [fontname="Helvetica,Arial,sans-serif"] //edge [fontname="Helvetica,Arial,sans-serif"] //rankdir="LR" node [fontsize=10, shape=record, height=0.25] edge [fontsize=10] virtio_dev_rx_single_packed -> vhost_enqueue_single_packed -> fill_vec_buf_packed -> vhost_flush_enqueue_shadow_packed }
软中断使用原则
常用调试方法