virtqueue_base.hpp

Go to the documentation of this file.

 
#pragma once
 
#include <cpu_io.h>
 
#include <cstdint>
 
#include "expected.hpp"
#include "virtio/virt_queue/misc.hpp"
 
namespace virtio {
 
class VirtqueueBase {
 public:
  [[nodiscard]] auto SubmitChainWithBarrier(
      this auto&& self, const IoVec* readable, size_t readable_count,
      const IoVec* writable, size_t writable_count) -> Expected<uint16_t> {
    // 写屏障：确保调用方填充的数据对设备可见
    cpu_io::Wmb();
    auto result =
        self.SubmitChain(readable, readable_count, writable, writable_count);
    if (result.has_value()) {
      cpu_io::Mb();
    }
    return result;
  }
 
  template <typename Callback>
  auto ProcessUsedWithCallback(this auto&& self, Callback&& callback)
      -> uint32_t {
    // 读屏障：确保读取到设备最新的 Used Ring 写入
    cpu_io::Rmb();
 
    uint32_t processed = 0;
    while (self.HasUsed()) {
      auto result = self.PopUsed();
      if (!result.has_value()) {
        break;
      }
 
      auto elem = *result;
      auto head = static_cast<uint16_t>(elem.id);
      callback(head, elem.len);
      (void)self.FreeChain(head);
      ++processed;
    }
    return processed;
  }
 
 protected:
  VirtqueueBase() = default;
  ~VirtqueueBase() = default;
  VirtqueueBase(VirtqueueBase&&) noexcept = default;
  auto operator=(VirtqueueBase&&) noexcept -> VirtqueueBase& = default;
  VirtqueueBase(const VirtqueueBase&) = delete;
  auto operator=(const VirtqueueBase&) -> VirtqueueBase& = delete;
};
 
}  // namespace virtio