Re: [PATCH v1 6/6] xen/riscv: relocating and unflattening host device tree

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

On 12/9/24 4:57 PM, Jan Beulich wrote:

> On 09.12.2024 16:56, Jan Beulich wrote:
> > On 27.11.2024 13:50, Oleksii Kurochko wrote:
> > > Relocate FDT to Xen heap instead of using early mapping as it is
> > > expected that discard_initial_modules() ( is supposed to call in
> > > the future ) discards the FDT boot module and remove_early_mappings()
> > > destroys the early mapping.
> > >
> > > Unflatten a device tree, creating the tree of struct device_node.
> > > It also fills the "name" and "type" pointers of the nodes so the normal
> > > device-tree walking functions can be used.
> > >
> > > Set device_tree_flattened to NULL in the case when acpi_disabled is
> > > equal to false.
> > >
> > > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> > >         
> > Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
> >
> > Albeit ...
> >
> > > @@ -71,6 +72,7 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
> > >                                 paddr_t dtb_addr)
> > >  {
> > >      const char *cmdline;
> > > +    size_t fdt_size;
> > >  
> > >      remove_identity_mapping();
> > >  
> > > @@ -95,7 +97,7 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
> > >                            _end - _start, false) )
> > >          panic("Failed to add BOOTMOD_XEN\n");
> > >  
> > > -    if ( !boot_fdt_info(device_tree_flattened, dtb_addr) )
> > > +    if ( !(fdt_size = boot_fdt_info(device_tree_flattened, dtb_addr)) )
> > >          BUG();
> > >         
> > ... perhaps better
> >
> >     fdt_size = boot_fdt_info(device_tree_flattened, dtb_addr);
> >     BUG_ON(!fdt_size);
> >
> > ?
> >       
> And then I notice that Arm has no such check at all. Better stay in sync?
>     
Agree, it is better to be in sync. I will drop the BUG_ON().

Thanks.

~ Oleksii