On Wed, Nov 21, 2018 at 2:15 PM Palmer Dabbelt <pal...@sifive.com> wrote: > > On Wed, 21 Nov 2018 13:49:53 PST (-0800), alistai...@gmail.com wrote: > > On Wed, Nov 21, 2018 at 1:26 PM Palmer Dabbelt <pal...@sifive.com> wrote: > >> > >> On Wed, 21 Nov 2018 10:32:45 PST (-0800), alistai...@gmail.com wrote: > >> > On Wed, Nov 21, 2018 at 10:05 AM Logan Gunthorpe <log...@deltatee.com> > >> > wrote: > >> >> > >> >> > >> >> > >> >> On 2018-11-21 10:02 a.m., Alistair Francis wrote: > >> >> > Connect the Xilinx PCIe device based on the information in the device > >> >> > tree stored in the ROM of the HiFish Unleashed board. > >> >> > >> >> I only briefly tested this patch but could not get any PCI devices to > >> >> come up with the sifive_u machine. Depending on the kernel I tried, it > >> >> either failed to initialize a Xilinx PCIe (likely due to a mismatch with > >> >> the DT) or it appears to successfully initialize a Microsemi device but > >> >> did not enumerate any devices underneath. > >> > > >> > That seems like either a kernel or bbl issue. > >> > > >> > You need to make sure that bbl doesn't edit the device tree (to add > >> > the Microsemi device or remove the Xilinx one) and ensure your kernel > >> > supports the Xilinx one. > >> > > >> >> > >> >> In any case, it would be nice if the Microsemi/Xilinx confusion was at > >> >> least explained in the commit message. > >> > > >> > What should we say? The QEMU machine accurately models the real > >> > hardware which reports a Xilinx PCIe. The confusion generally appears > >> > above QEMU where people are used to using the MicroSemi one. > >> > >> I think the real issue here is that "sifive_u" doesn't actually fully > >> describe > >> the device we're trying to emulate. Is it a: > >> > >> * Generic SiFive U core? In that case we just have a 64-bit core and > >> essentially no devices. This is kind of useless. > >> * A HiFive Unleashed? In that case there's no PCIe, as it requires an > >> expansion board. > >> * A HiFive Unleashed + VC707? Here we have Xilinx PCIe. > >> * A HiFive Unleashed + Microsemi Expansion? Here have Microsemi PCIe. > > > > This isn't even always consistent. For example the sifive_u machine > > exists for 32-bit cores, but the PCIe address reported by the hardware > > only works for 64-bit machines. > > > > So we need a trade off between accurately modelling the hardware or > > having 32-bit support. > > Yep, there's another issue. > > >> There's a tradeoff between accurately emulating the hardware and blowing > >> up the > >> amount of targets we support in QEMU. We went through this discussion > >> before > >> and ended up where we are now, but maybe it's best to go have the > >> discussion > >> again? > > > > Up to you, it is your board :) > > > > I think it makes more sense to remove these generic boards (that is > > what the virt board is for) and model real hardware boards. > > That seems reasonable to me. Is removing boards allowed? If so I'd be OK
It's possible, but takes some releases and deprecation warnings. You can see info about it here: https://qemu.weilnetz.de/doc/qemu-doc.html#Deprecated-features As it sounds like no one uses sifive u board (you can't specify a rootFS) it probably isn't that bad to remove. > renaming these to "sifive-hifive1" and "sifive-hifive-unleashed", and possibly > adding a "sifive-hifive-unleashed-vc707" as it's possible to emulate most of > that. Then we at least have accurate names for the boards. That sounds good to me. > > We do have an issue where I'd like to be able to have some system by which we > can configure the memory map of the target, but maybe that's separate > discussion. Yeah, that would also be nice, but I think is separate. Alistair
