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Shutemov" CC: Chao Peng , , , , , , , , , Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , , "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , , , , , , , , , Quentin Perret , , , Muchun Song , Subject: Re: [PATCH v9 1/8] mm: Introduce memfd_restricted system call to create restricted user memory Message-ID: <20221102212656.6giugw542jdxsvhh@amd.com> References: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> <20221025151344.3784230-2-chao.p.peng@linux.intel.com> <20221031174738.fklhlia5fmaiinpe@amd.com> <20221102211404.l5whyif3j3k67fv2@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20221102211404.l5whyif3j3k67fv2@box.shutemov.name> X-Originating-IP: [10.180.168.240] X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6NAM11FT081:EE_|SJ0PR12MB6783:EE_ X-MS-Office365-Filtering-Correlation-Id: de5815e3-d15f-4939-3067-08dabd1901fc X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: j2EItDXdgy1qVdqJxR4GEQrDaZ3DofdFzS+LNVJ6NsAJTMVFdBSp6zUpoaPvMWb6267FNjpOK3GF0L3xXcyq5uWRNLuq/Ufi4fc+ayxaUgAqwRo9rfluD4KybXiyZZkiAzOPeFB5kHGevljPKuxckYaN9ZREL/xrn9reHrF51j9Jtbtl4uHTHmj3fIYMmQVw1UvXacSTWAfgLOgY1ajIt+FHI7moRMF0bhhC1P6hC2h74Bu9XyAx4wShywFQZIoUbktcSgP2tS1Cs5jrQC/Oj3pWbOa9BZBYGZymrthBCap+Ro5nt2PPpjksvWECVuAPoXl12GfJIae/dQHmYbzGp4w01iMWCHWC9TnK9Ldx+q5jVs/o49bliHpyBYZDd8oIO8lsBU+FUjwFpFR2iu1qPlYZv51mMJoyUyMB9+hyUoVBR7coUvKyOPy0NguANTaArge8yyEuu7CphmRAvPo7bzFbIXHJU/b5j7a0E0zijVMfhWRVBz/nlXsZSKNYjjawjN4W7W4kjsz8ijEeKvj4kbLv5fGAsriKqEezuLPaSt08x+tqe4UI+TcxnHD4N1Sr1ZMjIyZlZFVONyxcmneXuOHmQiRerPQNmOSV7ylXag19ZczMTaJ6hI0iLDMwCBulYMjpw4eTEl243osrt4sPO67dBldmi9cTvkV+FBaRQxyxxKidT98W7E8jJE4xc8b2Ad4OdFhWzxOKa7QiuVKAsE/V9uxvLDLS6oCnFjdxCNz6+fidm5sAPmXEhy+X9qeMGvpjx5hupHqTkmx8jms/nYBjncmOrcR5JMWkY+VjwL8vWL+/Wq1dft740rMPewc/E4aOUi6BbVaeic5mLrHqbw== X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230022)(4636009)(376002)(396003)(136003)(39860400002)(346002)(451199015)(46966006)(40470700004)(36840700001)(47076005)(186003)(6666004)(26005)(36860700001)(54906003)(1076003)(478600001)(336012)(426003)(2616005)(40480700001)(83380400001)(2906002)(16526019)(40460700003)(44832011)(7406005)(82310400005)(70586007)(5660300002)(8676002)(70206006)(7416002)(8936002)(316002)(966005)(4326008)(41300700001)(86362001)(36756003)(82740400003)(81166007)(356005)(6916009)(36900700001);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Nov 2022 21:27:13.0077 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: de5815e3-d15f-4939-3067-08dabd1901fc 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: DM6NAM11FT081.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB6783 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 03, 2022 at 12:14:04AM +0300, Kirill A. Shutemov wrote: > On Mon, Oct 31, 2022 at 12:47:38PM -0500, Michael Roth wrote: > > > > In v8 there was some discussion about potentially passing the page/folio > > and order as part of the invalidation callback, I ended up needing > > something similar for SEV-SNP, and think it might make sense for other > > platforms. This main reasoning is: > > > > 1) restoring kernel directmap: > > > > Currently SNP (and I believe TDX) need to either split or remove kernel > > direct mappings for restricted PFNs, since there is no guarantee that > > other PFNs within a 2MB range won't be used for non-restricted > > (which will cause an RMP #PF in the case of SNP since the 2MB > > mapping overlaps with guest-owned pages) > > That's news to me. Where the restriction for SNP comes from? There's no > such limitation on TDX side AFAIK? > > Could you point me to relevant documentation if there's any? I could be mistaken, I haven't looked into the specific documentation and was going off of this discussion from a ways back: https://lore.kernel.org/all/YWb8WG6Ravbs1nbx@google.com/ Sean, is my read of that correct? Do you happen to know where there's some documentation on that for the TDX side? Thanks, Mike > > -- > Kiryl Shutsemau / Kirill A. Shutemov