On 9 March 2018 at 18:20, Guenter Roeck <li...@roeck-us.net> wrote: > On Fri, Mar 09, 2018 at 05:47:16PM +0000, Peter Maydell wrote: >> Thanks for that really useful writeup. So if I understand correctly >> we have several choices here: >> >> (1) we could implement a model of the IOMUX block that is at least >> sufficient to support guests that configure it to route the ENET interrupt >> line to a GPIO pin. Then we could apply this patch that fixes the ENET >> line definitions. Old kernels would continue to work (for the same >> reason they worked on hardware), and new ones would work now too. >> This is in some ways the preferred option, but it's possibly a lot >> of code and we're nearly in freeze for 2.12. >> >> (2) we could leave everything as it is for 2.12. This would mean that >> at least we don't regress setups that used to work on older QEMU versions. >> Downside is that we wouldn't be able to run Linux v4.15+, or other >> guest OSes that don't have the bug that older Linux kernels do. >> (Presumably we'd only do this on the understanding that we were going >> to go down route (1) for 2.13.) >> >> (3) we could apply this patch for 2.12. Linux v4.15+ now works, as >> do other guest OSes that use the ENET interrupt. v4.1 and older Linux >> guests that used to boot in QEMU stop doing so, and 4.2-4.9 boot but >> lose the ethernet device support. Perhaps for 2.13 we might >> take route (1) to make those older guests start working again. >> >> Do I have that right? >> > Pretty much. > >> None of these options seems especially palatable to me, so we're >> choosing the lesser evil, I think... (unless somebody wants to say >> that option (1) would be 20 lines of code and here's the patch :-)) >> I guess in the absence of (1) that (3) is better than (2) ? >> > > I would prefer (2). This is what I decided to use in my "local" > version of qemu. Older versions of Linux can be fixed by applying one > (4.2..4.9) or two (4.1 and older) upstream patches; anyone interested > running those kernels in qemu with Ethernet working should apply those > patches (or, alternatively, provide a patch adding IOMUX support to > qemu).
Did you mean "prefer (3) [apply this patch]" ? The rest of the paragraph makes more sense if you did. thanks -- PMM
