On Tue, Jun 23, 2026 at 06:17:33AM -0400, Zhenzhong Duan wrote:
> In coco guests, hotpluggable memory ranges are initially unaccepted.
> While a previous change expanded the unaccepted memory bitmap boundaries
> to include these hotplug spaces, the actual bits inside the bitmap are
> not yet marked as unaccepted.
>
> Walks SRAT a second time after the bitmap is allocated and sets the bits
> corresponding to hotpluggable ranges.
>
> This ensures the bitmap state accurately reflects all static and hotplug
> memory ranges before booting kernel.
>
> Signed-off-by: Zhenzhong Duan <[email protected]>
> ---
> .../firmware/efi/libstub/unaccepted_memory.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/firmware/efi/libstub/unaccepted_memory.c
> b/drivers/firmware/efi/libstub/unaccepted_memory.c
> index bfbb78bd7b8a..01bed8e751ca 100644
> --- a/drivers/firmware/efi/libstub/unaccepted_memory.c
> +++ b/drivers/firmware/efi/libstub/unaccepted_memory.c
> @@ -92,6 +92,23 @@ static void update_mem_boundaries(struct
> acpi_srat_mem_affinity *mem, struct sra
> *(ctx->mem_end) = range_end;
> }
>
> +static void mark_hotplug_memory_unaccepted(struct acpi_srat_mem_affinity
> *mem,
> + struct srat_parse_ctx *ctx)
> +{
> + u64 unit_size = unaccepted_table->unit_size;
> + u64 start, end;
> +
> + start = round_up(mem->base_address, unit_size);
> + end = round_down(mem->base_address + mem->length, unit_size);
We can get here with start > end if srat range is less then unit_size.
> +
> + /* Translate to offsets from the beginning of the bitmap */
> + start -= unaccepted_table->phys_base;
> + end -= unaccepted_table->phys_base;
> +
> + bitmap_set(unaccepted_table->bitmap,
> + start / unit_size, (end - start) / unit_size);
> +}
> +
> efi_status_t allocate_unaccepted_bitmap(__u32 nr_desc,
> struct efi_boot_memmap *map)
> {
> @@ -169,6 +186,7 @@ efi_status_t allocate_unaccepted_bitmap(__u32 nr_desc,
> unaccepted_table->phys_base = unaccepted_start;
> unaccepted_table->size = bitmap_size;
> memset(unaccepted_table->bitmap, 0, bitmap_size);
> + parse_acpi_srat_regions(mark_hotplug_memory_unaccepted, &ctx);
>
> status = efi_bs_call(install_configuration_table,
> &unaccepted_table_guid, unaccepted_table);
> --
> 2.52.0
>
--
Kiryl Shutsemau / Kirill A. Shutemov
