SR22 pilot reported smoke in the cabin due to a failed PFD panel.

Narrative

We were in cruise flight; enroute from ZZZ to ZZZ1. My wife and I smelled something burning. 10-20 seconds later; smoke started pouring out from behind the panel right at me. Within seconds; the cabin was filled with smoke. The smell of the smoke was electrical; so I immediately turned off all of the aircraft's electrical switches and initiated an immediate descent (I did not have time to make a radio call to ZZZ Approach; as the smoke was so heavy). I also opened all of the air vents full to get air moving through the cabin. After leveling off at approximately 3500 ft. MSL in VFR conditions; the smoke began to clear. However; we were now in the middle of the mountains with no electronics. The only items working on the aircraft were the engine; the backup airspeed indicator; the backup altimeter and the aircraft compass. I had a backup hand-held radio and planned to try and contact ATC on 121.5 but the cabin was so loud that I could not hear anything coming from the radio. After flying for 15-20 minutes; we found an airfield and attempted a landing but the runway was too short as we were making a no flaps landing. I initiated a go-around and flew generally northwest; as that would lead us out of the mountains. 15-20 minutes later; I finally found a highway and followed it west until I found a larger airport with a longer runway. I made two landing attempts but had to go-around both times due to aircraft on the runway (remember that we had no electrical power on the aircraft so we were NORDO). On the third attempt; I was able to get the aircraft down and stopped on Runway XX at ZZZ3. I had 7 voicemail messages on my phone from ZZZ1 TRACON and ZZZ Center. A Supervisor from ZZZ Center did call several minutes after landing and was very happy to learn that we had landed safely; since I essentially disappeared from radar coverage.Several days later; the airport's maintenance shop determined that the pilot's PFD had failed and had shorted out internally and was the source of the smoke. The aircraft was fully examined by the local A&P/IA and determined airworthy for flight for the return to our ZZZ1 home base with the PFD's circuit breakers pulled and the PFD placarded inoperative. The PFD will be sent back to Avidyne for replacement. Despite my over 30 years and nearly 7000 hours of flight experience; the lesson I learned was to always carry a backup satellite receiver (such as the Stratus 3B) and an iPad; so that I will always have a moving map and a source of flight information. I am very grateful that ATC went to such great lengths to help us (they even dispatched Search and Rescue to look for us; fearing that we had crashed in the mountains). I am also very grateful that I kept current on emergency procedures and had the training and skill to handle this emergency. I will also do a better job in the future of knowing exactly where we are in flight; in case we ever lose all communications with ATC again.