Hi Oleksandr, On Thu, 2 Dec 2021 at 22:41, Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com> wrote: > > Hi, Simon! > > On 02.12.21 19:57, Simon Glass wrote: > > Hi Oleksandr, > > > > On Thu, 2 Dec 2021 at 10:40, Oleksandr Andrushchenko > > <oleksandr_andrushche...@epam.com> wrote: > >> Hi, Simon! > >> > >> Sorry for being late to the party > >> > >> On 02.12.21 17:59, Simon Glass wrote: > >>> Add an empty file to prevent build errors when building with > >>> CONFIG_OF_SEPARATE enabled. > >>> > >>> The build instructions in U-Boot do not provide enough detail to build a > >>> useful devicetree, unfortunately. > >> Xen guest doesn't use any built-in device trees as the guest's device tree > >> is provided > >> by the Xen hypervisor itself and is generated at the virtual machine > >> creation time: it is > >> populated with memory size, number of CPUs etc. based on [1]. > >> So, even if we provide some device tree here it must not be used by U-boot > >> at > >> the end of the day. Thus, it might be a reasonable solution to provide an > >> empty device > >> tree as you do, but put a comment that it is not used. > > OK we can go with an empty one if we have to, but where are the > > instructions to create the DT that is used? > You don't need to create the device tree yourself, but instead it is > provided by Xen and generated at run-time while creating a > virtual machine. So, it is up to Xen to provide one. > There are cases [1] when you may want providing a so called > partial device tree to better tune what a virtual machine gets. > But again, it is used by Xen toolstack outside of the virtual machine > and serves as a sort of overlay to the generated device tree. > So, we can provide some device tree to be embedded in U-boot, > but it will have no practical meaning and will make more harm than good > > > > I'm not even sure how to run U-Boot with Xen? The in-tree instructions > > don't help... > This is just a virtual machine from Xen POV, so U-boot is nothing > different here from Linux kernel or anything else. > Thus no specific instructions are needed nor provided
I'd like to try it out. How?? Regards, Simon