[PATCH v6 23/34] x86, realmode: Decrypt trampoline area if memory encryption is active

Borislav Petkov bp at alien8.de
Wed Jun 14 09:39:04 PDT 2017


On Wed, Jun 14, 2017 at 06:24:16PM +0200, Borislav Petkov wrote:
> On Wed, Jun 07, 2017 at 02:17:09PM -0500, Tom Lendacky wrote:
> > When Secure Memory Encryption is enabled, the trampoline area must not
> > be encrypted. A CPU running in real mode will not be able to decrypt
> > memory that has been encrypted because it will not be able to use addresses
> > with the memory encryption mask.
> > 
> > A recent change that added a new system_state value exposed a warning
> > issued by early_ioreamp() when the system_state was not SYSTEM_BOOTING.
> > At the stage where the trampoline area is decrypted, the system_state is
> > now SYSTEM_SCHEDULING. The check was changed to issue a warning if the
> > system_state is greater than or equal to SYSTEM_RUNNING.
> 
> This piece along with the hunk touching system_state absolutely needs to
> be a separate patch as it is unrelated.

Btw, pls send this now and separate from the patchset as it is a bugfix
that should go into sched/core.

Thanks.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.



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