01 xc v70 burns oil, white smoke,

[JDS60R]

Sounds like you need a head gasket, repair of vacuum leak and replacement of effected sensors and possible catalyst replacement. Figure a few thousand.

If the smoke is grey or blue it would be a different story and could be a flame trap replacement. But white smoke usually means coolant in the combustion chamber. Go to napa or online and buy a coolant combustion gas test kit (about $14).
You put some coolant from your engine (while cold and not run for at least 6 hours into a test bottle and add a solution. if it turns color then you have confirmed a head gasket leak.

I am unsure of the value of a vehicle with the head gasket failure. You may not get back the money it take to fix it but you would be able to drive it safely again.

Are you sure the smoke is white?

[JDS60R]

I would change the flame trap before you lose the rear main seal. The oil loss is probably bein seen out the tailpipe.

Flame trap is an inexpensive job that any moderate level shadetree mechanic can do (have to pull the intake).

Change it out and see how she drives. If you can make money on selling it now thats great but I think you could get more if it wasn't blowing the oil.

If you think it is burning oil in other ways you can always rent a leak down tester to check.

I assume if you were loosing coolant you would let us know. Am I correct to assume yuo have not needed coolant and that this is an oil only concern?