On 3/21/23 11:05, nospam@godawa.de wrote:
Hi everybody,
since long time, I'm using Xen on CentOS with XL, currently latest CentOS 7 with Xen 4.15 from the CentOS-Xen-Project. For several VMs I have to use SR-IOV, to lower the CPU-usage on Dom0 on the host.
CentOS 7 comes to an end, Xen is not supported by RHEL nor RockyLinux anymore, so unfortunately I have to switch to KVM.
First step will be now, converting all the scripts for managing and running VMs, that they run with the additional libvirt-layer.
What is the libvirt version?
Mostly everything is working, but I do not get a network interface in the VM, when I start it with "virsh start ..." instead of "xl create ...".
First of all, is there documentation how to configure the VMs in the dom-definition for XEN (all docs I found are KVM-related)?
I know it's not complete, but https://libvirt.org/formatdomain.html makes an attempt to identify hypervisor support for the various configuration settings.
The converted xl-config does not do the job:
virsh -c xen:/// domxml-from-native --format xen-xl vm > vm.xml
These are some none working examples I tried out:
... <interface type='hostdev' managed='yes'> <mac address='02:16:32:10:20:30'/> <driver name='xen'/> <source> <address type='pci' domain='0x0000' bus='0x81' slot='0x02' function='0x6'/> </source> <vlan> <tag id='11'/> </vlan> </interface> ...
... <hostdev mode='subsystem' type='pci' managed='yes'> <driver name='xen'/> <source> <address domain='0x0000' bus='0x81' slot='0x02' function='0x6'/> </source> <address type='pci' domain='0x0000' bus='0x81' slot='0x02' function='0x6'/> </hostdev> ...
I've used both configurations successfully. Has the sriov virtual function been unbound from the native driver and bound to xen-pciback? You can check which driver is in use with something like ls /sys/bus/pci/devices/0000\:81\:02.6/driver If bound to xen-pciback, it vf should also appear in the output of 'xl pci-assignable-list'. Regards, Jim