If you don't already have an SSH public key in your account at http://bugs.illumos.org, generate a key pair like this on your machine (usually as the building/development user account):
$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/USER/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/USER/.ssh/id_rsa.
Your public key has been saved in /home/USER/.ssh/id_rsa.pub.
$ cat ~/.ssh/id_rsa.pub
Then paste your public key into the box on your account settings page at http://bugs.illumos.org and save the changes. Wait for a while for the change to propagate to the webrev server.
Creating and uploading a webrev
You should soon get a reply with additional feedback if needed, or a "thank you" for being part of the illumos developer community!