Re: [PATCH 2/4] x86/tdx: Use ReportFatalError to report missing SEPT_VE_DISABLE

Dave Hansen
2022-12-15T18:18:44Z

On 12/15/22 09:12, Kirill A. Shutemov wrote:
>> Getting *all* users of panic this magic ability would be a lot better
>> than giving it to one call-site of panic().
>>
>> I'm all for making the panic() path as short and simple as possible, but
>> it would be nice if this fancy hypercall would get used in more than one
>> spot.
> Well, I don't see an obvious way to integrate this into panic().
>
> There is panic_notifier_list and it kinda/sorta works, see the patch
> below.
>
> But it breaks panic_notifier_list contract: the callback will never return
> and no other callback will be able to do their stuff. panic_timeout is
> also broken.
>
> So ReportFatalError() is no good for the task. And I don't have anything
> else :/

Do we *really* have to do a hard stop when SEPT_VE_DISABLE is missing?

Wouldn't it be simpler to just defer the check until we can spit out a
sane error message about it?

Or is there too much security exposure by continuing?