lkml.org 
[lkml]   [2019]   [Jul]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] tpm: Document UEFI event log quirks
From
Date
On 7/5/19 3:26 AM, Jarkko Sakkinen wrote:
> On Wed, 2019-07-03 at 10:08 -0700, Jordan Hand wrote:
>>> +This introduces another problem: nothing guarantees that it is not
>>> +called before the stub gets to run. Thus, it needs to copy the final
>>> +events table preboot size to the custom configuration table so that
>>> +kernel offset it later on.
>>
>> This doesn't really explain what the size will be used for. Matthew's
>> patch description for "tpm: Don't duplicate events from the final event
>> log in the TCG2 log" outlines this well. You could maybe word it
>> differently but I think the information is necessary:
>>
>> "We can avoid this problem by looking at the size of the Final Event Log
>> just before we call ExitBootServices() and exporting this to the main
>> kernel. The kernel can then skip over all events that occured before
>> ExitBootServices() and only append events that were not also logged to
>> the main log."
>
> Not exactly sure what is missing from my paragraph. The way I see it has
> more information as it states what is used at as the vessel for
> exportation (the custom configuration table).
>
> Maybe something like:
>
> "Thus, it nees to save the final events table size at the time to the
> custom configuration table so that the TPM driver can later on skip the
> events generated during the preboot time."
>
Yes, that sounds more clear to me.

Thanks,
Jordan

\
 
 \ /
  Last update: 2019-07-08 06:12    [W:0.078 / U:0.668 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site