linux-kernel - RE: [Patch v3 05/14] x86/mm: Handle decryption/re-encryption of bss

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Message-ID: <SA1PR21MB1335D3133B884CA4221BB16DBF139@SA1PR21MB1335.namprd21.prod.outlook.com>
Date:   Mon, 28 Nov 2022 18:06:24 +0000
From:   Dexuan Cui <decui@...rosoft.com>
To:     Tom Lendacky <thomas.lendacky@....com>,
        "Michael Kelley (LINUX)" <mikelley@...rosoft.com>,
        Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        "hpa@...or.com" <hpa@...or.com>, KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        "wei.liu@...nel.org" <wei.liu@...nel.org>,
        "luto@...nel.org" <luto@...nel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "kuba@...nel.org" <kuba@...nel.org>,
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        "robh@...nel.org" <robh@...nel.org>, "kw@...ux.com" <kw@...ux.com>,
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        "arnd@...db.de" <arnd@...db.de>,
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        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
        "ak@...ux.intel.com" <ak@...ux.intel.com>,
        "isaku.yamahata@...el.com" <isaku.yamahata@...el.com>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        "jane.chu@...cle.com" <jane.chu@...cle.com>,
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        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>
Subject: RE: [Patch v3 05/14] x86/mm: Handle decryption/re-encryption of
 bss_decrypted consistently

> From: Tom Lendacky <thomas.lendacky@....com>
> Sent: Monday, November 28, 2022 6:16 AM
> > [...]
> > On a TDX system *with* CONFIG_AMD_MEM_ENCRYPT, the unused
> > memory in the bss_decrypted section also never gets freed due to the
> > below "return;"
> >
> > I'd suggest a Fixes tag should be added to make sure the distro vendors
> > notice the patch and backport it :-)
> > [...]
> > Fixes: b3f0907c71e0 ("x86/mm: Add .bss..decrypted section to hold shared
> variables")
> 
> I think the Fixes: tag should really be:
> 
> e9d1d2bb75b2 ("treewide: Replace the use of mem_encrypt_active() with
> cc_platform_has()")

Yes, you're correct.