On Fri, Jul 28, 2023 at 5:52 AM Bruce Ashfield <[email protected]> wrote:
> I'm travelling today, so I can't formulate a full answer at the moment. > > I just wanted to let everyone know that I have been reading and do > have an opinion which I'll send out when I get a chance to properly > write an email. > > I hadn't seen the patches in great detail before this send, so I need > to go through things and have a closer look. > > Generally speaking, I support having related recipes in a layer, as a > full reference stack. Perhaps there's a subset of things that are too > hardware/board specific, but again, I haven't looked in detail yet. > Layer "expansion" is also an issue for maintenance in the overall > ecosystem. Having too many layers is an issue for maintenance, along > with having too few layers that don't have a clean split between > distro/machine and functionality. > Even if some of this does land in a non-xilinx specific layer (that > isn't meta-virt), we'd be well served to have a README or other file > in meta-virt that explains how to build for hardware platforms. Having > only qemu available in meta-virt, and then having integrators wander > off into the wild world of non peer reviewed vendor layers and forks > of various components is something that I've been concerned about for > quite some time. > Thanks for replying -- the challenges of dealing with layer proliferation are real, which is part of what motivated the introduction of the dynamic layer for the Raspberry Pi board in support of enabling simpler testing, and I hadn't given that enough consideration in my response earlier. Without a reference document or direct example, it's not easy - it takes practical experience and persistence with it at the moment, so thanks for doing that work, Sandeep, and I apologise. The dynamic layers are good for enabling compatibility with composition and these changes are in support of a positive experience with enabling Xen platforms, so please continue. best, Christopher > > That all being said, don't take any of the above as more than my > initial thoughts. I'm extremely pleased to see Christophers review and > questions .. that's exactly what we need! > > Bruce > > > > On Fri, Jul 28, 2023 at 2:06 AM Christopher Clark > <[email protected]> wrote: > > > > +CC Bertrand > > > > On Thu, Jul 27, 2023 at 5:38 PM Sandeep Gundlupet Raju via > lists.yoctoproject.org <sandeep.gundlupet-raju= > [email protected]> wrote: > >> > >> Hi Chris, > >> > >> On 7/27/2023 6:10 PM, Christopher Clark via lists.yoctoproject.org > wrote: > >> > >> > >> On Thu, Jul 27, 2023 at 4:22 PM Sandeep Gundlupet Raju < > [email protected]> wrote: > >>> > >>> Add Xen dt and u-boot script support for AMD ZynqMP and Versal devices. > >> > >> > >> Hi Sandeep - this is a slightly surprising submission. I'm unsure about > meta-virtualization being the right place for this as typically hardware > enablement is more appropriately done in a BSP layer, where engineers who > have knowledge about and access to specific hardware can collaborate on > maintaining the machine-specific aspects of recipes. > >> > >> [Sandeep]: I checked with Bruce before I submit the patches, Since we > had xilinx dynamic layer, he has no objection in accepting the patches. > > > > > > That is generous, but I think you could make the layer maintenance > responsibilities easier and help with establishing good practice for > hardware support if these changes can go into a BSP layer instead, if that > is an option? I do appreciate that you are working on enabling Xen to work > on additional platforms. > > > > The Xilinx dynamic layer could be removed from meta-virtualization by > adding its Xen image creation logic to the primary Xen hypervisor recipe -- > possibly with a new mkimage task? -- to be enabled via new settings in an > Arm or Xilinx MACHINE configuration. > > > >> > >> Xen in this (non-BSP) layer has support for qemu MACHINES, plus generic > x86-64 and the Raspberry Pi 4 board for Arm platform coverage; the latter > is a special-case that has been discussed by Xen and Yocto community > members as a basic commodity reference hardware platform for testing (and > using) Xen, and the community for this layer has more of the interested > parties participating in it than meta-raspberrypi does. > >> > >> Are you experiencing difficulties with maintaining your Xen recipe > components in a separate layer? > >> > >> [Sandeep]: No we are not experiencing any difficulties in maintaining > these files, currently all the dtsi files are in meta-petalinux layer and > if users are using without meta-petalinux distro layer(building > xen-image-minimal), then Xen doesn't work on ZynqMP and Versal devices. > > > > > > Do you know which layer defines the MACHINE configurations for those > hardware devices? It seems like that could be a suitable BSP layer for > these changes? > > > >> > >> Mark Hatle and myself we discussed on this and we saw rpi u-boot script > and other files in this layer, we thought this is a good place to move > these files. > > > > > > I see how the raspberry pi dynamic layer can give that impression which > is unfortunate. The motivation for the inclusion of the rpi files in > meta-virtualization is to enable collaboration on hardware testing (and > reproduction and diagnosis if needed) of the Arm architecture functionality > of the primary Xen recipes, on a low-cost commodity hardware board, with > agreement on this from Xen stakeholders at multiple different > organizations. X86 doesn't need it as generic x86-64 support (see > meta-yocto-bsp) is enough. > > > > Christopher > > > > > >> > >> Mark can chime in here to add any additional comments. > >> > >> > >> Christopher > >> > >>> > >>> > >>> User can enable xen u-boot script by adding below variable from > >>> configuration file as shown below. > >>> > >>> BOOTMODE = "xen" > >>> > >>> This u-boot script also supports to configure below Xen params from > >>> configuration file. > >>> > >>> params variable assignment > >>> ------ ------------------- > >>> duart XEN_SERIAL_CONSOLES = "serial0" > >>> dom0_mem DOM0_MEM = "1500M" > >>> dom0_max_vcpus DOM0_MAX_VCPUS = "1" > >>> extra params XEN_CMDLINE_APPEND = "loglvl=all" > >>> > >>> Sandeep Gundlupet Raju (2): > >>> recipes-bsp: Add device-tree files for Xen support > >>> recipes-bsp: Add u-boot-xlnx scripts for Xen support > >>> > >>> .../device-tree/device-tree.bbappend | 19 +++ > >>> .../files/versal-net-xen-qemu.dtsi | 2 + > >>> .../device-tree/files/versal-net-xen.dtsi | 67 ++++++++++ > >>> .../device-tree/files/versal-xen-qemu.dtsi | 2 + > >>> .../device-tree/files/versal-xen.dtsi | 59 +++++++++ > >>> .../device-tree/files/zynqmp-xen-qemu.dtsi | 16 +++ > >>> .../device-tree/files/zynqmp-xen.dtsi | 123 ++++++++++++++++++ > >>> .../u-boot/u-boot-xlnx-scr.bbappend | 2 + > >>> .../u-boot/u-boot-xlnx-scr/boot.cmd.xen | 80 ++++++++++++ > >>> .../recipes-bsp/u-boot/xen-boot-cmd.inc | 38 ++++++ > >>> 10 files changed, 408 insertions(+) > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/device-tree.bbappend > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/files/versal-net-xen-qemu.dtsi > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/files/versal-net-xen.dtsi > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/files/versal-xen-qemu.dtsi > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/files/versal-xen.dtsi > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/files/zynqmp-xen-qemu.dtsi > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/device-tree/files/zynqmp-xen.dtsi > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/u-boot/u-boot-xlnx-scr.bbappend > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/u-boot/u-boot-xlnx-scr/boot.cmd.xen > >>> create mode 100644 > dynamic-layers/xilinx/recipes-bsp/u-boot/xen-boot-cmd.inc > >>> > >>> -- > >>> 2.34.1 > >>> > >> > >> > >> > >> > > > -- > - Thou shalt not follow the NULL pointer, for chaos and madness await > thee at its end > - "Use the force Harry" - Gandalf, Star Trek II >
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