On Mon, Jan 21, 2019 at 10:36:18AM -0800, Andi Kleen wrote: > > + /* Check the start address: needs to be page-aligned.. */ > > +- if (start & ~PAGE_MASK) > > ++ if (start & ~PAGE_MASK) { > > ++ > > ++ /* > > ++ * XXX Hack > > ++ * > > ++ * We re-use this error case to show case a cache load gadget: > > ++ * There is a mispredicted branch, which leads to prefetching > > ++ * the cache with attacker controlled data. > > ++ */ > > ++ asm volatile ( > > Obviously that can never be added to a standard kernel.
No, that's why it is a patch, right? People want to test things, it's nice to have a way to easily do this. > And I don't see much point in shipping test cases that require non > standard kernel patching. The idea of shipping test cases is that > you can easily test them, but in this form it can't. It's better than having nothing at all, which is what we have today. So I see no harm in it, only benefits. thanks, greg k-h