Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Received-SPF: Pass (protection.outlook.com: domain of amd.com designates
 165.204.84.17 as permitted sender) receiver=protection.outlook.com;
 client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C
Date:   Thu, 29 Jun 2023 16:02:04 -0500
From:   Michael Roth <michael.roth@amd.com>
To:     Borislav Petkov <bp@alien8.de>
CC:     <kvm@vger.kernel.org>, <linux-coco@lists.linux.dev>,
        <linux-mm@kvack.org>, <linux-crypto@vger.kernel.org>,
        <x86@kernel.org>, <linux-kernel@vger.kernel.org>,
        <tglx@linutronix.de>, <mingo@redhat.com>, <jroedel@suse.de>,
        <thomas.lendacky@amd.com>, <hpa@zytor.com>, <ardb@kernel.org>,
        <pbonzini@redhat.com>, <seanjc@google.com>, <vkuznets@redhat.com>,
        <jmattson@google.com>, <luto@kernel.org>,
        <dave.hansen@linux.intel.com>, <slp@redhat.com>,
        <pgonda@google.com>, <peterz@infradead.org>,
        <srinivas.pandruvada@linux.intel.com>, <rientjes@google.com>,
        <dovmurik@linux.ibm.com>, <tobin@ibm.com>, <vbabka@suse.cz>,
        <kirill@shutemov.name>, <ak@linux.intel.com>,
        <tony.luck@intel.com>, <marcorr@google.com>,
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        <alpergun@google.com>, <dgilbert@redhat.com>, <jarkko@kernel.org>,
        <ashish.kalra@amd.com>, <nikunj.dadhania@amd.com>,
        <liam.merwick@oracle.com>, <zhi.a.wang@intel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH RFC v9 05/51] x86/coco: move CONFIG_HAS_CC_PLATFORM check
 down into coco/Makefile
Message-ID: <20230629210204.tknoh7p3hw45jcp4@amd.com>
References: <20230612042559.375660-1-michael.roth@amd.com>
 <20230612042559.375660-6-michael.roth@amd.com>
 <20230620120920.GAZJGW8B6XHrsoLGCJ@fat_crate.local>
 <20230620204315.xr7wtcrowc7oprka@amd.com>
 <20230621085400.GDZJK6qMeOU2monJDv@fat_crate.local>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20230621085400.GDZJK6qMeOU2monJDv@fat_crate.local>
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Jun 2023 21:57:29.7373
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: f0427086-2cf8-440e-9a14-08db79b4fff1
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com]
X-MS-Exchange-CrossTenant-AuthSource: DM6NAM11FT078.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5062
X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,DATE_IN_PAST_24_48,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,
        RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_NONE,
        T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=no autolearn_force=no
        version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-crypto.vger.kernel.org>
X-Mailing-List: linux-crypto@vger.kernel.org

On Wed, Jun 21, 2023 at 10:54:00AM +0200, Borislav Petkov wrote:
> On Tue, Jun 20, 2023 at 03:43:15PM -0500, Michael Roth wrote:
> > Basically, arch/x86/coco/Makefile is never processed if arch/x86/Kbuild
> > indicates that CONFIG_HAS_CC_PLATFORM is not set. So if we want to have
> > stuff in arch/x86/coco/Makefile that build for !CONFIG_HAS_CC_PLATFORM,
> > like SNP host support, which does not rely on CONFIG_HAS_CC_PLATFORM
> > being set, that check needs to be moved down into arch/x86/coco/Makefile.
> 
> Ok, so if you put SNP host support into arch/x86/virt/svm/sev.c, that
> should work too and won't have any relation to CONFIG_HAS_CC_PLATFORM,
> right?

Right, that works out just as well, and ends up being a bit more
straightforward. I have it implemented here:

  https://github.com/mdroth/linux/commits/snp-host-latest-v9b

  https://github.com/mdroth/linux/commit/a889a2dd64b62d9c3bf74cf02e7d8d71c7061667

and dropped the patch that reworks arch/x86/coco/Makefile.

Thanks,

Mike

> 
> The CC_PLATFORM thing is a way to check for confidential computing guest
> features by abstracting the capabilities so that you don't have to check
> *each* and *every* conf guest type in the conditionals and thus go nuts.
> 
> Thx.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette