[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 00/19] arm64 EFI stub
On Wed, Jul 2, 2014 at 5:31 AM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote: > On Wed, 2014-07-02 at 12:52 +0100, Ian Campbell wrote: >> On Sat, 2014-06-28 at 02:25 +0100, Roy Franz wrote: >> > 2) Is it valid to start XEN with a device tree that only contains >> > multi-boot and EFI info? (As would be the case if the stub doesn't get a >> > device tree as input.) >> >> This would be the case when running on an ACPI system I guess? In which >> case everything which would be in the DT would instead be in the ACPI >> tables, which is something Naresh is working on I think. >> >> > Currently this isn't supported, some libfdt >> > functions are missing, so I'm checking if this is desired before I add >> > that. >> >> Unless this==booting with ACPI I'm not sure what it is and if its ACPI >> I'm not sure what needs to be done in the stub, could you explain >> please? >> >> (I have a feeling I'm missing something obvious) > > Ah, I think this is from the final patch: > >> + if ( fdtfile->ptr ) >> + fdt_size = fdt_totalsize(fdtfile->ptr); >> + else >> + { >> + /* RFRANZ_TODO - missing fdt_create_empty_tree() in libfdt. */ >> + return NULL; >> + } > > > I don't think we currently support booting with no FDT at all, and even > in the ACPI world we would get one. So I think this would be an error. > IOW no need to worry about it. > I think that for the ACPI-only case, the EFI stub will be the one responsible for creating the FDT for passing the UEFI/ACPI to the XEN kernel. (I had overlooked the ACPI-only case when considering the no-FDT case - for Linux we support this since a kernel could be configured such that it needs nothing from the FDT other than UEFI stuff, so we need to support it.) So I think we will need this, but only for the ACPI-only case. I'll look at adding the required libfdt file that provides fdt_create_empty_tree() - when I took a quick look it seemed that was in a file by itself. Matching the version of this new file with the existing libfdt may add some complication, but I'll look into it. Thanks, Roy _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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