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received-spf: None (protection.outlook.com: vmware.com does not designate permitted sender hosts) authentication-results: spf=none (sender IP is ) smtp.mailfrom=namit@vmware.com; x-microsoft-antispam-message-info: yov885qzC+H8B2L51HF+Lt+Asgo86Fb1DGsZ3t0azj9RVQNehQVcyosf91j5/+E4nAsb2qaFhrWRQjJYIUR+xBM4sPhS0MoUhqfRH2YzYo1ZBgCz5+MtegN3Wmocno29g13V5bWghJJkjwpA3Hw8WE/887iwrYLpEazDAOAoJJI= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="us-ascii" Content-ID: <606C13CC94DCAC45B5B64D63B3C506E4@namprd05.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: vmware.com X-MS-Exchange-CrossTenant-Network-Message-Id: f2577062-77dd-4a03-8e6e-08d57a3b1503 X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Feb 2018 21:27:31.5600 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b39138ca-3cee-4b4a-a4d6-cd83d9dd62f0 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY2PR05MB661 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Hansen wrote: >=20 > From: Dave Hansen >=20 > In creating its page tables, the espfix code masks its PGTABLE_PROT > value with the supported mask: __supported_pte_mask. This ensures > that unsupported bits are not set in the final PTE. But, it also > sets _PAGE_GLOBAL which we do not want for PTE. Use > __default_kernel_pte_mask instead which clears _PAGE_GLOBAL for PTI. Can you please explain what is your concern? Exposing more gadgets for speculative ROP attacks? Or is it a general rule of not exposing any kernel code &data more than absolutely necessary?