netdev - RE: [Patch v4 04/13] x86/mm: Handle decryption/re-encryption of bss

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Date:   Mon, 9 Jan 2023 19:14:54 +0000
From:   "Michael Kelley (LINUX)" <mikelley@...rosoft.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     "hpa@...or.com" <hpa@...or.com>, KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        "wei.liu@...nel.org" <wei.liu@...nel.org>,
        Dexuan Cui <decui@...rosoft.com>,
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Subject: RE: [Patch v4 04/13] x86/mm: Handle decryption/re-encryption of
 bss_decrypted consistently

From: Borislav Petkov <bp@...en8.de> Sent: Monday, January 9, 2023 11:11 AM
> 
> On Thu, Dec 29, 2022 at 04:25:16PM +0000, Michael Kelley (LINUX) wrote:
> > I'm ambivalent on the backport to stable.  One might argue that older
> > kernel versions are conceptually wrong in using different conditions for
> > the decryption and re-encryption.  But as you said, they aren't broken
> > from a practical standpoint because sme_me_mask and
> > CC_ATTR_MEM_ENCRYPT are equivalent prior to my patch set.  However,
> > the email thread with Sathyanarayanan Kuppuswamy, Tom Lendacky,
> > and Dexuan Cui concluded that a Fixes: tag is appropriate.
> 
> Right, just talked to Tom offlist.
> 
> A Fixes tag triggers a lot of backporting activity and if it is not really
> needed, then let's leave it out.
> 
> If distros decide to pick up vTOM support, then they'll pick up the whole set
> anyway.
> 
> And if we decide we really need it backported for whatever reason, we will
> simply send it into stable and the same backporting activity will be triggered
> then. But then we'd at least have a concrete reason for it.
> 
> Makes sense?
> 

Yep, that matches my thinking.  I've avoided marking something for stable unless
it fixes something that is actually broken.

Michael