From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934536AbdBQQnx (ORCPT ); Fri, 17 Feb 2017 11:43:53 -0500 Received: from mail-dm3nam03on0059.outbound.protection.outlook.com ([104.47.41.59]:36370 "EHLO NAM03-DM3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933900AbdBQQnt (ORCPT ); Fri, 17 Feb 2017 11:43:49 -0500 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=Thomas.Lendacky@amd.com; Subject: Re: [RFC PATCH v4 26/28] x86: Allow kexec to be used with SME To: Konrad Rzeszutek Wilk References: <20170216154158.19244.66630.stgit@tlendack-t1.amdoffice.net> <20170216154755.19244.51276.stgit@tlendack-t1.amdoffice.net> <20170217155756.GJ30272@char.us.ORACLE.com> CC: , , , , , , , , , Rik van Riel , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Toshimitsu Kani , Arnd Bergmann , Jonathan Corbet , Matt Fleming , "Michael S. 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Peter Anvin" , Borislav Petkov , Andrey Ryabinin , Thomas Gleixner , Larry Woodman , Dmitry Vyukov From: Tom Lendacky Message-ID: Date: Fri, 17 Feb 2017 10:43:37 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170217155756.GJ30272@char.us.ORACLE.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [165.204.77.1] X-ClientProxiedBy: BLUPR0401CA0028.namprd04.prod.outlook.com (10.162.114.166) To CY4PR12MB1142.namprd12.prod.outlook.com (10.168.163.150) X-MS-Office365-Filtering-Correlation-Id: 3d5b5a71-3b71-4fd0-77d2-08d457542379 X-MS-Office365-Filtering-HT: Tenant X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(48565401081);SRVR:CY4PR12MB1142; X-Microsoft-Exchange-Diagnostics: 1;CY4PR12MB1142;3:Wg4sMNfjbD8i0xFQpOkpyUCRWg+QvrzZmc0Xa7PVdDkgeEMwEtBWQTC2wmHSqmyZ7iM6itrk7PpmHrbybn4A2ZyUEm4gqkOEKztFIXVsl5Dh+/eBiIjYKCexgnEF+BC4NXE87LLLL56AexbpFMSaFiS/FyEQqdxZyxOlCNvv6uWYM4EeRw8alO6zdZ6pZXviWnwqxN7kR/9LBl5f+aug6YErDG3m6Yla311dRsDKTDJXSCb8kbqVMjrVpivxAYlI3mndAoVXZ/6UJwu8SD3cpAlaSoXR3YZWB1H8YmdWEpM=;25:cVRYMPUkSvc7sjTjqgUtebIZOI9z+5UZjtLujcH3qWuL1LaKwlEg1p8wt0ebXG5G//HFECHSAEWosf/BR7pjg6HZ+GGe6Zh1SLIkZFvVD8Qn3fJ122hl5jvm1iIny/PDxj2tOxs26d4w76XVMjpLCyxEwwxZr1gPdjD4LAJMuWq24nT73txQKNWFgfFrdRY7FxPkO+1RcuvuniSi42WE1a1ssAtjANDAEQRtF6FQtlvNKAtRpwuVnLnbBRTOiKzkbpZ1OEevbPOURTkeC0yIQh0mWo8/CTu8+ifpaDeX4moh9II6STJZC5NahaiKBhaMwcW/+O2PIAblHBQR2JZoTHE1BVtdFupqw6C4rUugmqZCxTxD7ggpnOSrIE9ESf/J7BEvb9Kt1Bc/wvK4CFbdJbBpc3QnXC7FXLi2/WEY5V6i8ZPyqwp1p8AxMKEoJCAJoEYakTIvzHuVYwEnuyZGXA== X-Microsoft-Exchange-Diagnostics: 1;CY4PR12MB1142;31:Tne+xGxGaADwIUm0WfXiKOV01TVed/+Fefic00it+2wkHxukAPSXjGCc1PtmLeBZQUftJKMYCohkX0K4P6YoymyspowHsbM2zQU09QbgkSIAxke7T08Xoq9QcLValH8SNPCZpEvDnPrzMxeaTN69CN3Jc7TJv2M8NX5wrQGmnuLwV/7wCLppS969Y0UXmx/KQWLCDHxRgSM/qSoj/e90ySRH7BBRi/SGthbSMPzKNw8=;20:zgHWKX6NQoN+JG6r0WfI22U7mzDF8Uin6uo2CPLR3UTMfvdhV6ofNaI6IexWJMbK5hM7FzQyOZQ9CLh4WJateLiHw5F3J8g1vLfGL71pEWEjiAubKBYTyhmOfcM8PZ1NbBEmg+kP/INGYm4D3ij6qIv67kYNdr7WFKrU2N1IfsO+wVYUArOjbaf9xL0K5/2jN7A9hNl7mco2Wl5EiD4rUZawMolP7t0lb2PWRAZYN7CThXlB+q5A6zEO6zxqCwqxXzd9CaFnD17EJhRwHl6rJRze+q57TQBXNVGLjBQGLL/3U15ZG7kdTJS+BiC25iJPrOUCUeJlFHHYqM/c+j+WF42FJip2xy7hg8W07JLGFmzpX9qh7yE4TxHOMQO5xQh/YqWRU4+RcFtLE+itVytJdPmmX6RNIBNtz9PdAhjrV6LsYn3x9L7p9ScOW6XdcXreQ0dEUs7T/VR3m1kgjlSsoOwu+T8dzMv7GPKusPoJW01TztCpxP2MuAtcHM3i7Qxl X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; 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But if the > rest of the memory is encrypted you won't get much, will you? Kexec can be used to reboot a system without going back through BIOS. So you can use kexec without using kdump. For kdump, just taking a quick look, the option to enable memory encryption can be provided on the crash kernel command line and then crash kernel can would be able to copy the memory decrypted if the pagetable is set up properly. It looks like currently ioremap_cache() is used to map the old memory page. That might be able to be changed to a memremap() so that the encryption bit is set in the mapping. That will mean that memory that is not marked encrypted (EFI tables, swiotlb memory, etc) would not be read correctly. > > Would it make sense to include some printk to the user if they > are setting up kdump that they won't get anything out of it? Probably a good idea to add something like that. Thanks, Tom > > Thanks. >