Ok, but what I meant is this, if we don't read from the descriptor ring, and validate all the other metadata supplied by the device (used id and len). Then there should be no way for the device to suppress the dma flags to write to the indirect descriptor table.
Or do you have an example how it can do that?
I don't. If you can validate everything it's probably ok
The only drawback is even more code to audit and test.
-Andi