Virtqueue Used Ring. More...

#include <split.hpp>

Collaboration diagram for virtio::SplitVirtqueue::Used:

Public Member Functions
auto	avail_event (uint16_t queue_size) volatile -> volatile uint16_t *
	获取 avail_event 字段的指针

auto	avail_event (uint16_t queue_size) const volatile -> const volatile uint16_t *

Public Attributes
uint16_t	flags
	标志位: UsedFlags (little-endian)

uint16_t	idx
	设备将下一个描述符条目放入环中的位置(模 queue_size) (little-endian)

UsedElem	ring []
	已用描述符元素数组 ring[queue_size]

Static Public Attributes
static constexpr size_t	kAlign = 4
	Used Ring 对齐要求(字节)

Detailed Description

Virtqueue Used Ring.

Used Ring 是设备完成缓冲区处理后返回它们的地方。它只由设备写入，由驱动程序读取。

Note: 实际 ring[] 大小由 queue_size 决定; 4 字节对齐

See also: virtio-v1.2#2.7.8 The Virtqueue Used Ring

Definition at line 158 of file split.hpp.

Member Function Documentation

◆ avail_event() [1/2]

auto virtio::SplitVirtqueue::Used::avail_event ( uint16_t queue_size ) const volatile -> const volatile uint16_t*

inline

Definition at line 186 of file split.hpp.

                           {
      const auto* byte_ptr = reinterpret_cast<const volatile uint8_t*>(ring);
      return reinterpret_cast<const volatile uint16_t*>(
          byte_ptr + sizeof(UsedElem) * queue_size);
    }

◆ avail_event() [2/2]

auto virtio::SplitVirtqueue::Used::avail_event ( uint16_t queue_size ) volatile -> volatile uint16_t*

inline

获取 avail_event 字段的指针

Parameters

queue_size 队列大小

Returns: avail_event 字段指针

Note: 仅当协商 VIRTIO_F_EVENT_IDX 特性时使用

See also: virtio-v1.2#2.7.10 Available Buffer Notification Suppression

Definition at line 178 of file split.hpp.

                              {
      // avail_event 位于 ring[queue_size] 之后，需要先转换为字节指针计算偏移
      auto* byte_ptr = reinterpret_cast<volatile uint8_t*>(ring);
      return reinterpret_cast<volatile uint16_t*>(byte_ptr + sizeof(UsedElem) *
                                                                 queue_size);
    }

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Member Data Documentation

◆ flags

uint16_t virtio::SplitVirtqueue::Used::flags

标志位: UsedFlags (little-endian)

Definition at line 162 of file split.hpp.

◆ idx

uint16_t virtio::SplitVirtqueue::Used::idx

设备将下一个描述符条目放入环中的位置(模 queue_size) (little-endian)

Definition at line 164 of file split.hpp.

◆ kAlign

constexpr size_t virtio::SplitVirtqueue::Used::kAlign = 4

staticconstexpr

Used Ring 对齐要求(字节)

Definition at line 160 of file split.hpp.

◆ ring

UsedElem virtio::SplitVirtqueue::Used::ring[]

已用描述符元素数组 ring[queue_size]

Definition at line 168 of file split.hpp.

The documentation for this struct was generated from the following file:

/workspaces/SimpleKernel/src/device/virtio/virt_queue/split.hpp

Public Member Functions

Public Attributes

Static Public Attributes