Virtio

qemu-system-x86_64 \
# vda - 存储
-drive file=alpine.qcow2,if=virtio \
# 网络
-netdev user,id=user.0,hostfwd=tcp::4287-:22 \
-device virtio-net,netdev=user.0

# PCI 10 GbE virtio-net-pci
-net nic,model=virtio

# libvirt <memballoon model='virtio' autodeflate='on'>
-device virtio-balloon,deflate-on-oom=on

# Linux AIO
-drive file=disk.qcow2,if=virtio,aio=native,cache.direct=on

# RNG/Random Number Generator
# =========================
# 默认
# 支持限速 例如 512 bytes/s -> max-bytes=512,period=1000
-device virtio-rng-pci
# UNIX 环境
-object rng-random,filename=/dev/random,id=rng0
# 硬件 rng
-object rng-random,filename=/dev/hwrng,id=rng0
# 网络 RNG
-chardev socket,host=10.199.13.151,port=9000,id=chr0 -object rng-egd,chardev=chr0,id=rng0

<domain>
  <!-- 单线程 -->
  <iothreads>1</iothreads>
  <disk type='file' device='disk'>
    <!-- 单线程 -->
    <driver name='qemu' type='raw' cache='none' iothread='1'/>
    <!-- virtio -->
    <target dev='vda' bus='virtio'/>
  </disk>
  <devices>
    <controller type='scsi' index='0' model='virtio-scsi'>
      <!-- 单线程 -->
      <driver iothread='1'/>
    </controller>
  </devices>
</domain>

# cluster_size 提高性能
qemu-img create -f qcow2 -o cluster_size=2M my.qcow2 100G

# 设置 cache-size 提高性能
qemu-system-x86_64 -drive file=my.qcow2,if=none,id=drive0,aio=native,cache=none,cache-size=16M

# mode
# off - 不预先申请
# falloc - 使用 posix_fallocate() 预留空间
# full - 填 0 预留
qemu-img create -f $fmt -o preallocation=$mode test.img 100G

# 启动 daemon
virtiofsd --socket-path=/var/run/vm001-vhost-fs.sock -o source=/var/lib/fs/vm001

# -virtfs local,path=/tank/storage,mount_tag=host0,security_model=passthrough,id=host0

# QEMU
qemu-system-x86_64 \
  -chardev socket,id=char0,path=/var/run/vm001-vhost-fs.sock \
  -device vhost-user-fs-pci,chardev=char0,tag=myfs \
  -object memory-backend-memfd,id=mem,size=4G,share=on \
  -numa node,memdev=mem
# Guest 挂载
mount -t virtiofs myfs /mnt


# virtfs-proxy-helper