Product : Oracle, Oracle VM/3.4, x86 Edition
Feature : Max vCPU per VM, VM Config , Hypervisor
Content Owner:  Roman Macek
Summary
128 (Windows) & 256 (Linux)
Details
This max number will vary accordingly to Guest Type and Architecture. More info on: http://docs.oracle.com/cd/E64076_01/E76173/html/vmrns-limits.html