In virtual hardware version 6 (Workstation 6.0.x releases), the VMCI virtual device is not present by default. After you upgrade a virtual machine’s virtual hardware to version 7, the following line appears in the .vmx configuration file, and when the virtual machine powers on, a new vmci0.id line also appears there.
vmci0.present = "TRUE"
In virtual hardware version 7 (Workstation 6.5 releases), the VMCI virtual device is present by default. When you create a virtual machine, the .vmx configuration file contains lines specifying PCI slot number and the ID of the VMCI device. On the vmci0.id line, CID is the number in double quotes.
vmci0.pciSlotNumber = "36" vmci0.id = "1066538581"
The VMCISock_GetLocalCID() Function
For convenience, you can call the VMCISock_GetLocalCID() function to obtain the local system’s CID. This function works on both the ESXi host and guest virtual machines, although the ESXi host always has CID = 2, even in a nested virtual machine (VM running in a VM).