On Tue, Nov 22, 2022 at 03:49:29PM -0600, Tom Lendacky wrote:
> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> index cb5f0befee57..a0bfd31358ba 100644
> --- a/drivers/firmware/efi/libstub/x86-stub.c
> +++ b/drivers/firmware/efi/libstub/x86-stub.c
> @@ -23,7 +23,7 @@
> const efi_system_table_t *efi_system_table;
> const efi_dxe_services_table_t *efi_dxe_table;
> -u32 image_offset;
> +u32 image_offset __section(".data");
> static efi_loaded_image_t *image = NULL;
> static efi_status_t
>
> I assume it has to do with being in .data vs .bss and not being explicitly
> cleared with the encryption bit set. With the change to put image_offset in
> the .data section, it is read as zero, where as when it was in the .bss
> section it was reading "ciphertext".
Hmm, two points about this:
1. Can we do
u32 image_offset __bss_decrypted;
here instead? We have this special section just for that fun and it
self-documents this way.
2. Also, why does my SEV-ES guest boot just fine without that change?
[ 0.000000] Linux version 6.1.0-rc6+ (root@ml) (gcc (Debian 11.3.0-1) 11.3.0, GNU ld (GNU Binutils for Debian) 2.38) #1 SMP PREEMPT_DYNAMIC Wed Nov 23 11:27:17 CET 2022
...
[ 0.336132] Memory Encryption Features active: AMD SEV SEV-ES
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
