Hmm... I don't have an ESP32-S3 to test, but looking at one of the esp32s3 linux builds online[1], the binaries are compiled for the xtensa arch. So it does seem to run natively rather than through some kind of emulation. Linux's source does have an arch/xtensa/ directory, so that arch seems to be supported on some level by the kernel. ESP32-S3's docs also mention having an MMU[2], though it's possible it's not sufficiently featureful.
Interesting! I've only seen the older projects which probably predate the ESP32-S3. I wonder how usable this is in reality though because you typically can only buy modules with up to 8MB of PSRAM, so you'd have to swap the PSRAM out for higher capacity or manufacture a custom board.
