lkml.org 
[lkml]   [2018]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: RFC: userspace exception fixups
Date
On 2018-11-02 10:01, Andy Lutomirski wrote:
> On Fri, Nov 2, 2018 at 9:56 AM Jethro Beekman <jethro@fortanix.com> wrote:
>>
>> On 2018-11-02 09:52, Sean Christopherson wrote:
>>> On Fri, Nov 02, 2018 at 04:37:10PM +0000, Jethro Beekman wrote:
>>>> On 2018-11-02 09:30, Sean Christopherson wrote:
>>>>> ... The intended convention for EENTER is to have an ENCLU at the AEX target ...
>>>>>
>>>>> ... to further enforce that the AEX target needs to be ENCLU.
>>>>
>>>> Some SGX runtimes may want to use a different AEX target.
>>>
>>> To what end? Userspace gets no indication as to why the AEX occurred.
>>> And if exceptions are getting transfered to userspace the trampoline
>>> would effectively be handling only INTR, NMI, #MC and EPC #PF.
>>>
>>
>> Various reasons...
>>
>> Userspace may have established an exception handling convention with the
>> enclave (by setting TCS.NSSA > 1) and may want to call EENTER instead of
>> ERESUME.
>>
>
> Ugh,
>
> I sincerely hope that a future ISA extension lets the kernel return
> directly back to enclave mode so that AEX events become entirely
> invisible to user code.

Can you explain how this would work for things like #BR/#DE/#UD that
need to be fixed up by code running in the enclave before it can be resumed?

--
Jethro Beekman | Fortanix

[unhandled content-type:application/pkcs7-signature]
\
 
 \ /
  Last update: 2018-11-02 18:06    [W:0.071 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site