qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: net_client_init_fun call 10 + switch=virbr0 + '[' -n tap1 ']' ++ whoami + ip tuntap add tap1 mode tap user root ioctl(TUNSETIFF): Device or resource busy + ip link set tap1 up + sleep 0.5s + ip link set tap1 master virbr0 + exit 0 qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_net_init call vhost_dev_init qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_dev_init call hdev->vhost_ops->vhost_backend_init 、host_set_owne、 vhost_get_features qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_dev_init call vhost_virtqueue_init qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: vhost_virtqueue_init vhost_set_vring_call : File descriptor in bad state (77) qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_dev_init call vhost_virtqueue_init qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: vhost_virtqueue_init vhost_set_vring_call : File descriptor in bad state (77) qemu-system-aarch64: info: vhost_net_start vhost_net_start_one qemu-system-aarch64: info: vhost.c vhost_dev_start qemu-system-aarch64: vhost_dev_start call vhost_set_mem_table: No buffer space available (105) qemu-system-aarch64: vhost_dev_start call vhost_virtqueue_start: No buffer space available (105) qemu-system-aarch64: vhost_virtqueue_start: No buffer space available (105) qemu-system-aarch64: vhost_dev_start call vhost_virtqueue_start: Resource temporarily unavailable (11) qemu-system-aarch64: vhost_virtqueue_start: Resource temporarily unavailable (11) qemu-system-aarch64: info: tcp_chr_connect call qemu_chr_be_event CHR_EVENT_OPENED ---nc 连接时
#define _VHOST_DEBUG 1 #ifdef _VHOST_DEBUG #define VHOST_OPS_DEBUG(fmt, ...) do { error_report(fmt ": %s (%d)", ## __VA_ARGS__, strerror(errno), errno); } while (0) #else #define VHOST_OPS_DEBUG(fmt, ...) do { } while (0) #endif
虚拟机侧
主机侧
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: net_client_init_fun call 10 + switch=virbr0 + '[' -n tap1 ']' ++ whoami + ip tuntap add tap1 mode tap user root ioctl(TUNSETIFF): Device or resource busy + ip link set tap1 up + sleep 0.5s + ip link set tap1 master virbr0 + exit 0
[root@localhost ~]# brctl show bridge name bridge id STP enabled interfaces virbr0 8000.5254000d3f71 yes enp125s0f1 tap1 virbr0-nic [root@localhost ~]#
+ switch=virbr0
+ '[' -n tap1 ']'
++ whoami
+ ip tuntap add tap1 mode tap user root
ioctl(TUNSETIFF): Device or resource busy
+ ip link set tap1 up
+ sleep 0.5s
+ ip link set tap1 master virbr0
+ exit 0
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_net_init call vhost_dev_init
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_dev_init call hdev->vhost_ops->vhost_backend_init 、host_set_owne、 vhost_get_features
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_dev_init call vhost_virtqueue_init
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_virtqueue_init vhost_set_vring_call
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_dev_init call vhost_virtqueue_init
qemu-system-aarch64: -netdev tap,ifname=tap1,id=network-0,vhost=on,script=../qemu-ifup,vnet_hdr=on: info: vhost_virtqueue_init vhost_set_vring_call
qemu-system-aarch64: info: vhost_net_start vhost_net_start_one
qemu-system-aarch64: info: vhost.c vhost_dev_start
qemu-system-aarch64: info: vhost_dev_start call vhost_set_mem_table
qemu-system-aarch64: info: vhost_dev_start call vhost_virtqueue_start
qemu-system-aarch64: info: vhost_virtqueue_start
qemu-system-aarch64: info: vhost_virtqueue_start vhost_set_vring_kick
qemu-system-aarch64: info: vhost_dev_start call vhost_virtqueue_start
qemu-system-aarch64: info: vhost_virtqueue_start
qemu-system-aarch64: info: vhost_virtqueue_start vhost_set_vring_kick
-object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge1
主机侧
虚拟机侧
设置了numa参数
最后我们看下设置了numa参数的情况，我们刚才说之前两种情况都不能满足vhost_user的使用，因为无法内存共享。那么我们看下使用vhost_user时的qemu参数的例子：
-object memory-backend-file,id=ram-node0,prealloc=yes,mem-path=/dev/hugepages/,share=yes,size=17179869184 -numa node,nodeid=0,cpus=0-29,memdev=ram-node0
没错我们需要指定numa参数，同时也要指定mem-path。numa参数的会导致在parse_numa函数中解析，并对nb_numa_nodes++。这里还有注意，指定了numa时也指定了memory-backend-file参数，这会导致qemu创建一个struct HostMemoryBackend内存对象(object)。
下面我们回到memory_region_allocate_system_memory具体分析。