Re: [RFC PATCH 1/4] efi/libstub: Decouple memory bitmap from the unaccepted table

From: Kiryl Shutsemau

Date: Wed Nov 26 2025 - 06:08:08 EST


On Tue, Nov 25, 2025 at 11:57:50AM -0600, Pratik R. Sampat wrote:
> Memory hotplug in secure environments requires the unaccepted memory
> bitmap to grow as new memory is added. Currently, the bitmap is
> implemented as a flexible array member at the end of struct
> efi_unaccepted_memory, which is reserved by memblock at boot and cannot
> be resized without reallocating the entire structure.
>
> Replace the flexible array member with a pointer.

Well, it break interoperability between kernel before and after the
patch. Consider kexec from kernel without the patch to the kernel with
the patch and then back to older kernel. It is ABI break.

Is re-allocating the entire structure such a big pain?

--
Kiryl Shutsemau / Kirill A. Shutemov