Re: [BUG] Fault during memory acceptance for TDX VMs with certain memory sizes

[Moritz Sanft <ms@edgeless.systems>]

> What about the patch below. It seems we under-reserve memory for the
> table if it is unaligned.
> 
> I still think that we need align start/size/end to the PAGE_SIZE in
> accept_memory()/range_contains_unaccepted_memory() before doing anything
> else. Otherwise (end % unit_size) check is broken. But it seems to be
> unrelated to the problem you see.
> 
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 111e87a618e5..56e9d73412fa 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -692,13 +692,13 @@ static __init int match_config_table(const efi_guid_t *guid,
>  
>  static __init void reserve_unaccepted(struct efi_unaccepted_memory *unaccepted)
>  {
> -	phys_addr_t start, size;
> +	phys_addr_t start, end;
>  
>  	start = PAGE_ALIGN_DOWN(efi.unaccepted);
> -	size = PAGE_ALIGN(sizeof(*unaccepted) + unaccepted->size);
> +	end = PAGE_ALIGN(efi.unaccepted + sizeof(*unaccepted) + unaccepted->size);
>  
> -	memblock_add(start, size);
> -	memblock_reserve(start, size);
> +	memblock_add(start, end - start);
> +	memblock_reserve(start, end - start);
>  }
>  
>  int __init efi_config_parse_tables(const efi_config_table_t *config_tables,

Thanks, this patch seems to fix the problem causing the panic. The VM 
boots as expected with this.

Please let me know if any more information is required.

Best Regards,
Moritz Sanft