Re: [RFC] efi/tpm: add efi.tpm_log as a reserved region in 820_table_firmware

[Usama Arif <usamaarif642@gmail.com>]

On 12/09/2024 14:10, Ard Biesheuvel wrote:
> Does the below help at all?
> 
> --- a/drivers/firmware/efi/tpm.c
> +++ b/drivers/firmware/efi/tpm.c
> @@ -60,7 +60,7 @@ int __init efi_tpm_eventlog_init(void)
>         }
> 
>         tbl_size = sizeof(*log_tbl) + log_tbl->size;
> -       memblock_reserve(efi.tpm_log, tbl_size);
> +       efi_mem_reserve(efi.tpm_log, tbl_size);
> 
>         if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) {
>                 pr_info("TPM Final Events table not present\n");

Unfortunately not. efi_mem_reserve updates e820_table, while kexec looks at /sys/firmware/memmap
which is e820_table_firmware.

arch_update_firmware_area introduced in the RFC patch does the same thing as efi_mem_reserve does at
its end, just with e820_table_firmware instead of e820_table.
i.e. efi_mem_reserve does:
	e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
	e820__update_table(e820_table);

while arch_update_firmware_area does:
	e820__range_update_firmware(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED);
	e820__update_table(e820_table_firmware);

Thanks,
Usama