Re: [Xen-devel] [PATCH v7 08/36] x86/mm: Add support to enable SME in early boot processing

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

On Wed, 21 Jun 2017, Tom Lendacky wrote:
> On 6/21/2017 10:38 AM, Thomas Gleixner wrote:
> >     /*
> >      * Sanitize CPU configuration and retrieve the modifier
> >      * for the initial pgdir entry which will be programmed
> >      * into CR3. Depends on enabled SME encryption, normally 0.
> >      */
> >     call __startup_secondary_64
> > 
> >          addq    $(init_top_pgt - __START_KERNEL_map), %rax
> > 
> > You can hide that stuff in C-code nicely without adding any cruft to the
> > ASM code.
> > 
> 
> Moving the call to verify_cpu into the C-code might be quite a bit of
> change.  Currently, the verify_cpu code is included code and not a
> global function.

Ah. Ok. I missed that.

> I can still do the __startup_secondary_64() function and then look to
> incorporate verify_cpu into both __startup_64() and
> __startup_secondary_64() as a post-patch to this series.

Yes, just having __startup_secondary_64() for now and there the extra bits
for that encryption stuff is fine.

> At least the secondary path will have a base C routine to which
> modifications can be made in the future if needed.  How does that sound?

Sounds like a plan.

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