On Fri, Oct 27, 2017 at 8:38 AM, Florian Weimer <fweimer@redhat.com> wrote:
On 10/26/2017 11:09 PM, Alexander Ploumistos wrote:
On Thu, Oct 26, 2017 at 11:28 PM, Jeff Backus <jeff.backus@gmail.com> wrote:
Yes, we would need a +4GB RAM machine to test the PAE end of it, but
any machine should be able to leverage the NX part of it.

The first NX-capable CPUs on the AMD side were Athlon 64 and P4 for
Intel, right?
Does that mean that we need to support 32-bit installations on 64-bit
systems in general, or just the P4s?

I don't quite understand this discussion.  Why does this even matter? You just test on the hardware you've got, and that's it.  If it supports NX/XD, fine, but if it does not, that's okay as well.  It's just another dimension in the test matrix, along with any other minor architecture revision which was introduced over the years.

It's not that the 32-bit PAE/NX code paths are something revolutionary new at this point.  To me, it seems completely reasonable to assume that upstream isn't doing anything completely broken.  I'm pretty sure that not disabling PAE/NX support will bring the Fedora x86 kernel more in line with what else is out there, too.

 No, not new and revolutionary, but a gross hack, a code path that is much less tested, and where errors are much more likely to (and do) show up. If there were a ton of hardware with NX support and 32bit only, this might be worth a discussion, but most NX capable hardware is also x86_64.  PAE should have died a long time ago.