On Mon, Aug 22, 2022 at 10:49:09AM +0100, Robin Murphy wrote: > Hmm, it's possible this might be quietly fixed by 20347fca71a3, but either > way I'm not sure why we would need to panic *before* we've even tried to > allocate anything, when we could simply return with no harm done? If we've > ended up calculating (or being told) a buffer size which is too small to be > usable, that should be no different to disabling SWIOTLB entirely. Hmm. I think this might be a philosophical question, but I think failing the boot with a clear error report for a configuration that is supposed to work but can't is way better than just panicing later on. > Historically, passing "swiotlb=1" on the command line has been used to save > memory when the user knows SWIOTLB isn't needed. That should definitely not > be allowed to start panicking. I've never seen swiotlb=1 advertized as a way to disable swiotlb. That's always been swiotlb=noforce, which cleanly disables it.