Can't advise how to fix--can only tell you what was done in my kitchen. I would've preferred to level the floor under the house by mu GC advised against it as being extremely costly so we elected to fix by shimming cabinets. First (and I wish in hindsight it was before I placed my cabinet order), they shot a laser at each corner of my cabinet run to determine the high point in kitchen where to start. It was approximately 3/4" out of lever over any one cabinet run. From the high point, cabinets where all shimmed up to finished floor height (3/4") with plywood, then extra shimming was done as needed in order to get the cabinets leveled. This, of course, raised up the overall height of the cabinets (luckily we have a vaulted ceiling and only presented an issue with one staggered height corner cabinet where crown will die into ceiling in one corner). The hardwood was then laid--obviously floor is still not completely level, but not noticeably out of level either. My installer will lastly trim down 6" toe kick to fill in the gaps. Not perfect, but very workable and you'd never know the difference now that we're in the homestretch.

HTH!