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

[Oleksii Kurochko]

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.kuroc...@gmail.com>

Acked-by: Jan Beulich<jbeul...@suse.com>

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