On Wed, 29 Jan 2025 10:14:34 +0900 Itaru Kitayama <itaru.kitay...@linux.dev> wrote:
> > On Jan 22, 2025, at 23:07, Jonathan Cameron <jonathan.came...@huawei.com> > > wrote: > > > > On Fri, 17 Jan 2025 09:43:11 +0000 > > Jonathan Cameron via <qemu-devel@nongnu.org> wrote: > > > >> On Fri, 17 Jan 2025 10:13:41 +0900 > >> Itaru Kitayama <itaru.kitay...@linux.dev> wrote: > >> > >>>> On Jan 16, 2025, at 19:58, Jonathan Cameron > >>>> <jonathan.came...@huawei.com> wrote: > >>>> > >>>> On Thu, 16 Jan 2025 15:04:53 +0900 > >>>> Itaru Kitayama <itaru.kitay...@linux.dev> wrote: > >>>> > >>>>> Hi Jonathan, > >>>>> > >>>>>> On Jan 14, 2025, at 19:26, Jonathan Cameron > >>>>>> <jonathan.came...@huawei.com> wrote: > >>>>>> > >>>>>> On Tue, 14 Jan 2025 12:03:03 +0900 > >>>>>> Itaru Kitayama <itaru.kitay...@linux.dev> wrote: > >>>>>> > >>>>>>> Hi Jonathan, > >>>>>>> > >>>>>>>> On Jan 10, 2025, at 21:31, Jonathan Cameron > >>>>>>>> <jonathan.came...@huawei.com> wrote: > >>>>>>>> > >>>>>>>> On Fri, 10 Jan 2025 09:20:54 +0000 > >>>>>>>> "Zhijian Li (Fujitsu)" via <qemu-devel@nongnu.org> wrote: > >>>>>>>> > >>>>>>>>> On 10/01/2025 13:29, Itaru Kitayama wrote: > >>>>>>>>>> Hi, > >>>>>>>>>> Is anybody working on the CXL emulation on aarch64? > >>>>>>>>> > >>>>>>>>> I'm not currently working on the CXL emulation on aarch64. > >>>>>>>>> > >>>>>>>>> However, IIRC the CXL maintainer's tree should work. > >>>>>>>>> https://gitlab.com/jic23/qemu/ > >>>>>>>> > >>>>>>>> Pick up latest branch from there. I'm prepping a rebased version > >>>>>>>> with some new stuff but might take a few more days. > >>>>>>> > >>>>>>> Thanks for sharing your work with us. Your master and cxl-2024-11-27 > >>>>>>> branches give: > >>>>>>> > >>>>>>> $ qemu-system-aarch64: -accel tcg,cxl=on: Property 'tcg-accel.cxl' > >>>>>>> not found > >>>>>> > >>>>>> cxl is a machine property not a accel one. So needs to be after virt > >>>>>> There are tests in the tree for bios tables. Copy the command line > >>>>>> from those. > >>>>>> > >>>>>>> > >>>>>>> My commands are below: > >>>>>>> $HOME/projects/qemu/build/qemu-system-aarch64 \ > >>>>>>> -M virt,virtualization=on,gic-version=3 \ > >>>>>>> -M acpi=off -cpu max,sme=off -m 8G -smp 4 \ > >>>>>>> -accel tcg,cxl=on \ > >>>>>>> -nographic \ > >>>>>>> -bios $HOME/cca-v4/out/bin/flash.bin \ > >>>>>>> -kernel Image-cca \ > >>>>>>> -drive > >>>>>>> format=raw,if=none,file=$HOME/cca-v4/out-or/images/rootfs.ext2,id=hd0 > >>>>>>> \ > >>>>>>> -device virtio-blk-pci,drive=hd0 \ > >>>>>>> -append root=/dev/vda \ > >>>>>>> -nodefaults \ > >>>>>>> --serial tcp:localhost:54320 \ > >>>>>>> -serial tcp:localhost:54321 \ > >>>>>>> -append "root=/dev/vda earlycon console=hvc0" \ > >>>>>>> -device virtio-net-pci,netdev=net0 \ > >>>>>>> -netdev user,id=net0 \ > >>>>>>> -device virtio-9p-device,fsdev=shr0,mount_tag=shr0 \ > >>>>>>> -fsdev local,security_model=none,path=../../,id=shr0 > >>>>>>> > >>>>>>> Yes, I’m using Linaro’s CCA capable OP-TEE builds above. > >>>>>> > >>>>>> I'm a little curious why optee is relevant for this but shouldn't > >>>>>> matter as long > >>>>>> as an appropriate EDK2 is loaded. > >>>>>> > >>>>> > >>>>> I picked up your tree’s “master” and “cxl-next” as of today, and only > >>>>> the latter at least booted. > >>>>> The former gives: > >>>>> > >>>>> qemu-system-aarch64: Property 'virt-9.2-machine.cxl' not found > >>>>> > >>>>> Should I stick with the cxl-next? My concern is that the base QEMU > >>>>> version is a bit old > >>>>> 7.0.50. > >>>> > >>>> Always use the latest dated branch on that tree. I release whenever > >>>> there > >>>> is something new to carry or a major rebase needed. > >>>> > >>>> cxl-<date> is the right branch to use. Hope that helps. > >>> > >>> When do you think you want to get them (aarch64 specific?) merged > >>> mainline. Any reason you want to carry the patches by yourself? > >> > >> Nothing much has changed since I presented on this at Linaro connect in > >> 2023. > >> https://resources.linaro.org/en/resource/hM986DSHfoTrZ98UjpvLg1 > >> > >> The issue is device tree bindings for PCI Expander bridgess and the fact > >> that > >> those need to be generated without the full enumeration that EDK2 is doing > >> prior to ACPI final table builds. In order to move forward with that it > >> needs a bunch of work to prove that we absolutely cannot get patches > >> upstream to support kernel base enumeration and breaking up of the > >> various resources (like EDK2 does). > > > > I was talking to Peter Maydell earlier and given developments in the last > > couple > > of years that have by necessity been ACPI only in arm virt he is less > > opposed to ACPI only features being added where device tree is challenging. > > > > So we may be able to move forwards without device tree support. > > > > The PXB enumeration question is also relevant for managing multiple > > vIOMMUs to represent multiple physical IOMMUs with the correct isolation > > and do it efficiently which is probably a more pressing usecase than CXL > > emulation. > > The discussion was mainly about that usecase, but maybe it also unblocks > > upstreaming this support. > > > > Thanks, > > > > Jonathan > > I finally made some CXL tests ran within the ndctl test framework along with > the kernel modules (QEMU is on your cxl-2024-11-27 branch) on aarch64. > However, the recent rebase cxl-2025-01-24 fails to start the system emulation > > qemu-system-aarch64: Property 'virt-10.0-machine.cxl' not found > > The build did not complain, what kind of tests you run against your > periodical QEMU rebase? On this run I was focused on chmu testing which will have included what you are running into here. It's made a little tricky by some local networking issues so getting a branch up on gitlab is far from straight forward. Ah. Looks like the push went wrong as that has 0 patches on top of main qemu branch so that branch is effectively empty. Typo in what I pushed. Sorry about that. Note this is far from a production tree as it carries many patches with outstanding review comments etc. Mainly exists for the purposes of testing specific kernel patches where the support is not ready for upstream QEMU yet. It is not in any sense a 'release' with the sort of testing that would imply, so mostly a case of local smoke tests. Any help with more comprehensive tests would be much appreciated. I know some other folk in the CXL community are talking about that, but I don't think anyone has it in place yet. It's hard as there are typically a lot of moving parts. Pushed now. Jonathan > > Itaru. > > > > >> > >> Given PXB enumeration in kernel has some issues on ARM anyway (that you > >> can paper > >> over with _DSM 5 - it self requiring an extra patch that isn't > >> upstreamable because > >> of IO port issues) there is quite a bit of work needed, mostly not in QEMU. > >> Or convince Peter and others that not all virt support needs DT bindings > >> (note that PXB for PCIE has been supported for years without an DT support, > >> just no one noticed!) > >> > >> After that we'd need to figure out CXL DT bindings in general and add > >> kernel > >> code support - despite there being no known DT based CXL systems out > >> there, so > >> that is going to be hard to do. Various CXL kernel maintainers have > >> expressed > >> they aren't against such support, but it's hardly going to be review > >> priority > >> (other than for me if someone else does the work!) > >> > >> For me this isn't particularly high priority. The ARM bit is fairly easy > >> to rebase. > >> I would like to see it solved, but it is behind various other items on my > >> backlog. > >> > >> There are SBSA machine patches on list, but it's not a useful platform for > >> CXL kernel code development because of the limited supported configurations > >> (in keeping with the more or less fixed model that SBSA-ref uses). > >> > >> Jonathan > >> > >> > >> > >>> > >>> Itaru. > >>> > >>>> > >>>> Jonathan > >>>> > >>>>> > >>>>> Thanks, > >>>>> Itaru. > >>>>> > >>>>>> Jonathan > >>>>>> > >>>>>>> > >>>>>>> Let me know which branch you were suggesting. > >>>>>>> > >>>>>>> Thanks, > >>>>>>> Itaru. > >>>>>>> > >>>>>>>> > >>>>>>>> Note my main development work is on arm64 so that tends to work > >>>>>>>> more reliably than x86 which I only lightly test for stuff that > >>>>>>>> isn't ready for upstream yet. > >>>>>>>> > >>>>>>>> Give me a shout if you run into any problems. > >>>>>>>> > >>>>>>>> The main blocker on upstreaming this is resolving the missing device > >>>>>>>> tree > >>>>>>>> support for PCI expander bridges. I've not made any progress on > >>>>>>>> this since > >>>>>>>> talk at Linaro connect in 2023. > >>>>>>>> > >>>>>>>> Jonathan > >>>>>>>> > >>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Thanks > >>>>>>>>> Zhijian > >>>>>>>>> > >>>>>>>>>> If there’s a WIP branch, a pointer would be appreciated. > >>>>>>>>>> > >>>>>>>>>> Itaru > >
