Re: [libvirt] [PATCH 06/12] virInterface: Expose link state & speed

On Fri, May 30, 2014 at 01:41:08PM +0200, Michal Privoznik wrote: > On 30.05.2014 10:56, Daniel P. Berrange wrote: >> On Thu, May 29, 2014 at 10:32:40AM +0200, Michal Privoznik wrote: >>> Currently it is not possible to determine the speed of an interface >>> and whether a link is actually detected from the API. Orchestrating >>> platforms want to be able to determine when the link has failed and >>> where multiple speeds may be available which one the interface is >>> actually connected at. This commit introduces an extension to our >>> interface XML (without implementation to interface driver backends): >>> >>> <interface type='ethernet' name='eth0'> >>> <start mode='none'/> >>> <mac address='aa:bb:cc:dd:ee:ff'/> >>> <link speed='1000' state='up'/> >>> <mtu size='1492'/> >>> ... >>> </interface> >>> >>> Where @speed is negotiated link speed in Mbits per second, and state >>> is the current NIC state (can be one of the following: "unknown", >>> "notpresent", "down", "lowerlayerdown","testing", "dormant", "up"). >> >> This is fine for the the <interface> objects, but it is limited >> in usefulness for SRIOV use cases. The <interface> objects only >> exist for interfaces which are configured for the host. With >> SRIOV passthrough some of the interfaces we're interested in >> are not going to be configured - they're just bare devices >> waiting to be given to a guest. > > I hear what you're saying, but unless a PCI device is given interface name I > am afraid we can't do anything. For instance, if you have a NIC but detach > it from the driver (echo ${PCI_ADDR} > > /sys/bus/pci/drivers/<driver>/unbind), kernel still sees the PCI device > (it's shown in lspci output for instance), but it's not configured anymore - > kernel doesn't know device link state, hence it's not aware if NIC's link > speed, etc. So tools like ethtool, ip, ifconfing won't show the device. IIUC, We have three classes of device 1 Devices not bound - no NIC visible in the host OS 2 Devices bound but not configured. NIC visible in host OS, but no /etc/sysconfig/networking/ifcfg-XXX file 3 Devices bound and configured. NIC visible in host OS, and has a /etc/sysconfig/networking/ifcfg-XXX file The <interface> configs only let you deal with NIC devices in class 3. The <nodedev> XML / APIs let you see NIC devices in class 2 + 3.