cfg2cmd: netdev: fix value for tx_queue_size

Quoting from QEMU commit 4271f40383 ("virtio-net: correctly report
maximum tx_queue_size value"):

> Maximum value for tx_queue_size depends on the backend type.
> 1024 for vDPA/vhost-user, 256 for all the others.

> So the parameter is silently ignored and ethtool reports a different
> value than the one provided by the user.

Indeed, for a non-vDPA/vhost-user netdev, the guest will see TX: 256
instead of the specified 1024 here. With the mentioned QEMU commit (in
master and will be part of 8.1), using 1024 will be a hard error:

> Invalid tx_queue_size (= 1024), must be a power of 2 between 256 and 256

Since neither vhost-user, nor vhost-vdpa netdev types are exposed by
Proxmox VE, just changing the limit to the correct 256 should be fine.
No obvious issue during live-migration found.

Fixes: 620d6b32 ("virtio-net: increase defaults rx|tx-queue-size to 1024")
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>

PVE/QemuServer.pm

@@ -1774,7 +1774,7 @@ sub print_netdevice_full {
     }
 
     if (min_version($machine_version, 7, 1) && $net->{model} eq 'virtio'){
-	$tmpstr .= ",rx_queue_size=1024,tx_queue_size=1024";
+	$tmpstr .= ",rx_queue_size=1024,tx_queue_size=256";
     }
 
     $tmpstr .= ",bootindex=$net->{bootindex}" if $net->{bootindex} ;

test/cfg2cmd/efidisk-on-rbd.conf.cmd

@@ -28,5 +28,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=pc+pve0'

test/cfg2cmd/ide.conf.cmd

@@ -35,5 +35,5 @@
   -drive 'file=/var/lib/vz/images/100/vm-100-disk-2.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=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=pc+pve0'

test/cfg2cmd/netdev-7.1-multiqueues.conf.cmd

@@ -22,5 +22,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on,queues=2' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,vectors=6,mq=on,packed=on,rx_queue_size=1024,tx_queue_size=1024,bootindex=300,host_mtu=900' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,vectors=6,mq=on,packed=on,rx_queue_size=1024,tx_queue_size=256,bootindex=300,host_mtu=900' \
   -machine 'type=pc+pve0'

test/cfg2cmd/netdev-7.1.conf.cmd

@@ -22,5 +22,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300,host_mtu=900' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300,host_mtu=900' \
   -machine 'type=pc+pve0'

test/cfg2cmd/q35-ide.conf.cmd

@@ -34,5 +34,5 @@
   -drive 'file=/var/lib/vz/images/100/vm-100-disk-2.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=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-linux-hostpci-mapping.conf.cmd

@@ -32,5 +32,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-linux-hostpci-multifunction.conf.cmd

@@ -32,5 +32,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-linux-hostpci-x-pci-overrides.conf.cmd

@@ -31,5 +31,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-linux-hostpci.conf.cmd

@@ -37,5 +37,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/q35-simple.conf.cmd

@@ -25,5 +25,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=q35+pve0'

test/cfg2cmd/qemu-xhci-7.1.conf.cmd

@@ -33,5 +33,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=pc+pve0'

test/cfg2cmd/qemu-xhci-q35-7.1.conf.cmd

@@ -25,5 +25,5 @@
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A1,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'type=pc-q35-7.1+pve0'

test/cfg2cmd/seabios_serial.conf.cmd

@@ -29,5 +29,5 @@
   -drive 'file=/var/lib/vz/images/8006/vm-8006-disk-0.qcow2,if=none,id=drive-scsi0,discard=on,format=qcow2,cache=none,aio=io_uring,detect-zeroes=unmap' \
   -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=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
-  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=1024,bootindex=300' \
+  -device 'virtio-net-pci,mac=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
   -machine 'smm=off,type=pc+pve0'