Why do KVM guests show vnet interface link speed as 10Mbps

Issue

• ethtool reports speed of a vnet interface as 10Mbps on KVM guest machine.

# ethtool vnet1
Settings for vnet1:  
 Supported ports: [ ]  
 Supported link modes:  
 Supports auto-negotiation: No  
 Advertised link modes:  Not reported  
 Advertised pause frame use: No  
 Advertised auto-negotiation: No  
 Speed: 10Mb/s   
 Duplex: Full  
 Port: Twisted Pair  
 PHYAD: 0  
 Transceiver: internal  
 Auto-negotiation: off  
 MDI-X: Unknown  
 Current message level: 0xffffffa1 (-95)  
 Link detected: yes