QEMU not more than 6 virtual network cards?

[afink]

I have a strange behaviour. I just added network card #7 to a VM and it doesn't pop up in the VM as usual
Card 0...5 work. #6 does not. they are all configured the same way but with different VLAN tags

in the proxmox config file I can see

net0: virtio=E2:2F:32:E8:3F:4A,bridge=vmbr0,tag=801
net1: virtio=26:B5:66:CB:75:0B,bridge=vmbr0,tag=807
net2: virtio=52:8B:99:63:71:01,bridge=vmbr0,tag=808
net3: virtio=42:5C:E8:2A:58:73,bridge=vmbr0,tag=804
net4: virtio=1A:6E:56:A41:47,bridge=vmbr0,tag=805
net5: virtio=D6:BE:09:67:20:8D,bridge=vmbr0,tag=817
net6: virtio=FA:78:19:20:26:34,bridge=vmbr0,tag=820

I can see the QEMU process is started with

-netdev type=tap,id=net0,ifname=tap208i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=E2:2F:32:E8:3F:4A,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=102

-netdev type=tap,id=net1,ifname=tap208i1,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=26:B5:66:CB:75:0B,netdev=net1,bus=pci.0,addr=0x13,id=net1

-netdev type=tap,id=net2,ifname=tap208i2,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=52:8B:99:63:71:01,netdev=net2,bus=pci.0,addr=0x14,id=net2

-netdev type=tap,id=net3,ifname=tap208i3,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=42:5C:E8:2A:58:73,netdev=net3,bus=pci.0,addr=0x15,id=net3

-netdev type=tap,id=net4,ifname=tap208i4,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=1A:6E:56:A41:47,netdev=net4,bus=pci.0,addr=0x16,id=net4

-netdev type=tap,id=net5,ifname=tap208i5,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=D6:BE:09:67:20:8D,netdev=net5,bus=pci.0,addr=0x17,id=net5

-netdev type=tap,id=net6,ifname=tap208i6,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=FA:78:19:20:26:34,netdev=net6,bus=pci.1,addr=0x1,id=net6


the only thing which I can spot is the PCI address on net6 which is pci.1 addr=0x1 where all the others are pci.0


The guest operating system is Debian10.

Anyone have any idea what this could cause?

 

[mikesrus]

if you make software router inside vm, maybe better choice to create trunk to vm an setup tagged vlan inisde VM?

 

[afink]

its not a router. its a VM which has to talk to different subnets for different tasks. a storage system, a database, two reduntant internal ip networks, two redundant DMZ networks one public ip.

Its cleaner to have a separate network interface in the VM than to pass through a VLAN tagged interface. But yes this could be done indeed if that really fails.

I just dont understand where this limit is coming from as it doesnt make any sense to me.
Debian 11 has the same issue. I just checked.

 

[spirit]

do you have tried to stop/start the vm ?

net6->net31 are on another pci bridge, and it need to be hotplugged too.

I'm 100% sure that it was working the in the past, but I dont have tested since 2-3 years.

if it's start fine, can you send the full kvm command line ?

 

[afink]

yes full stop/start is the first thing I tried.

/usr/bin/kvm
-id 209
-name XXXX
-no-shutdown
-chardev socket,id=qmp,path=/var/run/qemu-server/209.qmp,server=on,wait=off
-mon chardev=qmp,mode=control
-chardev socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5
-mon chardev=qmp-event,mode=control
-pidfile /var/run/qemu-server/209.pid
-daemonize
-smbios type=1,uuid=ea413770-ede5-4ac9-988a-12f68e41c0bc
-smp 8,sockets=1,cores=8,maxcpus=8
-nodefaults
-boot menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg
-vnc unix:/var/run/qemu-server/209.vnc,password=on
-cpu kvm64,enforce,+kvm_pv_eoi,+kvm_pv_unhalt,+lahf_lm,+sep
-m 6144
-device pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e
-device pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f
-device vmgenid,guid=3680a8db-aa66-4a38-bf9b-a7554ab59822
-device piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2
-device usb-tablet,id=tablet,bus=uhci.0,port=1
-device VGA,id=vga,bus=pci.0,addr=0x2
-chardev socket,path=/var/run/qemu-server/209.qga,server=on,wait=off,id=qga0
-device virtio-serial,id=qga0,bus=pci.0,addr=0x8
-device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on
-iscsi initiator-name=iqn.1993-08.org.debian:01:f8f2cc5cdc7
-drive if=none,id=drive-ide2,media=cdrom,aio=io_uring
-device ide-cd,bus=ide.1,unit=0,drive=drive-ide2,id=ide2,bootindex=200
-device virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5
-drive file=/mnt/pve/qserver45-vm/images/209/vm-209-disk-0.qcow2,if=none,id=drive-scsi0,format=qcow2,cache=none,aio=io_uring,detect-zeroes=on
-device scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100
-netdev type=tap,id=net0,ifname=tap209i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=76:F8:29:88:EE:7C,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300
-netdev type=tap,id=net1,ifname=tap209i1,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=2A:54:C2:BE:59:EC,netdev=net1,bus=pci.0,addr=0x13,id=net1,bootindex=301
-netdev type=tap,id=net2,ifname=tap209i2,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=D6:F1:CA:81:85:CC,netdev=net2,bus=pci.0,addr=0x14,id=net2,bootindex=302
-netdev type=tap,id=net3,ifname=tap209i3,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=9E9:A9:6F:4F:86,netdev=net3,bus=pci.0,addr=0x15,id=net3,bootindex=303
-netdev type=tap,id=net4,ifname=tap209i4,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=EE:A8:B1:18:FF:BC,netdev=net4,bus=pci.0,addr=0x16,id=net4,bootindex=304
-netdev type=tap,id=net5,ifname=tap209i5,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
-device virtio-net-pci,mac=0A:29:6C:A7F:11,netdev=net5,bus=pci.0,addr=0x17,id=net5,bootindex=305
-netdev type=tap,id=net6,ifname=tap209i6,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown
-device vmxnet3,mac=62:F8:CA:C0:C1:9E,netdev=net6,bus=pci.1,addr=0x1,id=net6,bootindex=306
-machine type=pc+pve0

 

[spirit]

the net6 is a vmware vmxnet3 nic ?

-netdev type=tap,id=net6,ifname=tap209i6,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown
-device vmxnet3,mac=62:F8:CA:C0:C1:9E,netdev=net6,bus=pci.1,addr=0x1,id=net6,bootindex=306

(maybe another test, as It was correctly virtio-net is your first post ?)


command line seem to be ok.

was it the result of "lspci" in your vm ? do you see all nics ?