Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <80f3d7b9-e3d5-b2c0-7707-710bf6f5081e@intel.com>
Date:   Tue, 22 Feb 2022 11:19:11 -0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Firefox/91.0 Thunderbird/91.6.0
Subject: Re: [PATCH V2 19/32] x86/sgx: Support adding of pages to an
 initialized enclave
Content-Language: en-US
To:     Jarkko Sakkinen <jarkko@kernel.org>
CC:     <dave.hansen@linux.intel.com>, <tglx@linutronix.de>,
        <bp@alien8.de>, <luto@kernel.org>, <mingo@redhat.com>,
        <linux-sgx@vger.kernel.org>, <x86@kernel.org>, <seanjc@google.com>,
        <kai.huang@intel.com>, <cathy.zhang@intel.com>,
        <cedric.xing@intel.com>, <haitao.huang@intel.com>,
        <mark.shanahan@intel.com>, <hpa@zytor.com>,
        <linux-kernel@vger.kernel.org>
References: <cover.1644274683.git.reinette.chatre@intel.com>
 <fcbde9c3e67289eaff9cd8b34989919629fe823c.1644274683.git.reinette.chatre@intel.com>
 <YhDbGfzGWQ5RtwTU@iki.fi> <YhDb/QRYMa4+xsyv@iki.fi> <YhKLNqgPNNLS7JyN@iki.fi>
From:   Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <YhKLNqgPNNLS7JyN@iki.fi>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?M3BIY1pSK1V4aiswamlYbmdtdHQ4TUZPdDdRL2NNU25taFNLVVk0Nk96RDZ3?=
 =?utf-8?B?bytLaWpUV3huWk5MYXgweEhYaDhvQk41My9KMzZXSU1mV002YnkvSXdYbVJn?=
 =?utf-8?B?dFk2YzQ0WGR3TDBvTkl4WlR6OWhFS05HeXFXVDY5OEk1Z0FsZ0g3TGNLWWc3?=
 =?utf-8?B?elF0NU5SSDBpTGR4NUJ6SkpQdnpOencrWHY1czR0NWcvcER3dWxYcEVFdTJB?=
 =?utf-8?B?aW1JV2xReTV6Z3cvRzljM1FGT1BrMnBpc2RnU3d4QTF4N1FQaHhnTDVScFRF?=
 =?utf-8?B?eU9JV3liTzlBYmJ2ZlBGeGlOcWpSZ3k3NkY3SkNQcVBMdHNPaUtHbFV6ZnJs?=
 =?utf-8?B?cCtsM3dZUWxKaWhlSzFkZ2tDd3dDNnFnWXhIRHJ4WUpoc0dUbnljV3ZKSjNi?=
 =?utf-8?B?ZjM5bHJydXk3emluQkQvVS8yekxmUVRkQ0JUSWZuaUVvRG8rbzIxN2F3NzZm?=
 =?utf-8?B?TlZ2elNJbzd0MHAybmF3bng1OU9ycmVkbnlyOE1JeCt5Sk5Ed1JEUTlCL2pl?=
 =?utf-8?B?QzdPSWt6SDMzWnNRMmJ6b3hGdUJ2c2NZQUE5NERqY1piSW5lT1ZzNFUxOEJq?=
 =?utf-8?B?ejlnY1pFNFFaeWRyZDE1WDA3YUxhQmtwdXhMSlBNM3dEbDJxViszZ1NneXVh?=
 =?utf-8?B?V1JGazRUK3kvQlc2QTBkd3pucjkyV0ljenU5alEwN0ZjSUxqZm1yMDNTQjl1?=
 =?utf-8?B?UW5MR3QzbzhTbnk0eGo3NXQ3VFkxUXVqM1lGVzVtRHVEKzZNaVQ0SjhWV2tN?=
 =?utf-8?B?K3IrZ3NJSkIvaDJQTGZIY0lLTXFCclJvaUxIdG91b1pxZysvalpsSkd3aWQr?=
 =?utf-8?B?SUVoeEVjTGxhSGpweGQrM0pqNDB2Z1BoZExQSUZsN2NaUjhZT2crTHd0a1V3?=
 =?utf-8?B?a2Fjai9uZkV5SjJreU1mQzFXbG0zTnozVGxuSENvb205QnhkdmpKdE9DVG9I?=
 =?utf-8?B?bTY0TlhaV1ZndURPV2xtSm9lbXdLOFdaMElGQW8weG1RVjhFV1o5VFdMMUY4?=
 =?utf-8?B?cmFSTTE2d3oxMlZ0cDVXbGczZFgzSmpoc1hSMlBhMGttRXlabmVFRGRCV0Ix?=
 =?utf-8?B?SDBSM283UktqMmpzK1llT0UvdTVMNCtpcVVSZSt4NFpCZXVTYy9nRjI4bk1U?=
 =?utf-8?B?cGpZNlpvN0FsejFmdjlkbXF2bGJHVVpwWktUb2tBSDNGSTdvYmJ3bFAvclAw?=
 =?utf-8?B?bStsMXFkYStxK21hQmFXWEdZZjB3ZklkdGpJdExNcmc1WGxuV0RETTRmNCs4?=
 =?utf-8?B?SzlTdlMySmVIdCtIM0xVVFI0ZmZUdWdSbjY1WjJxUU90eE9oZzRuU3VmdUxt?=
 =?utf-8?B?emdZSXNQMXBzYisxMTcwMlQrQ21XSllEbmRvUVJUc3FZWWlERVVzMDdpVzIx?=
 =?utf-8?B?SkdLYm8wRE5vT3FmVURBTFZVRU1KeXVQRUo1TFlqMTNMWVNyWGg0SVNSQ1BM?=
 =?utf-8?B?b216eUFjSXR3SkdLNTJKeEdIQ3VXVlVqTS9Wa3ZYNEJPY0pOZC9UQ2sxT0dK?=
 =?utf-8?B?KzFlVjhrZm9OU0NKUWNWVVVMQ2VrbUVzZjdOcWJ1djZPV0R2R3pQckwrdVIv?=
 =?utf-8?B?Yjh0d1RibXhxbThmRDZFQWpyV1J6RVNNUC9ZdFp3R1BzV3RJeHpKOXJPc3c1?=
 =?utf-8?B?dHNnWnk5ajJoWGp2YzU5YXBPSlZaMG9UY3FraGs5emg5Z3dXc2JCYTFNTmdX?=
 =?utf-8?B?bjQ2MG40TEhaNGhncklEdFZKQ3M3OTRWMmlVZHdEUWVOWWlhcXM3SDcxTDVl?=
 =?utf-8?B?N1NibWIxekZLTjlZUUI1ODJkdmpLcWsrRFcybVlkV25QQ3AzS0tEMlRuQzRU?=
 =?utf-8?B?SkFqN3VOUm5MSzEvRTQwU01XTlZTR1cyMG1ydDR4NE0yd2lEaGdwbVVZd2l3?=
 =?utf-8?B?KzY0NHY3NmZkZW1OaWwxZ09QWk9qNWI3MXJwUHlyalJkSXRPUUdGRWJvY0ZP?=
 =?utf-8?B?SEFlYlhPbS9RSXVXUWF3Q2wzMDRVSDhLa2JHRmZrRlV5VGtoNzdsZ3hxd24z?=
 =?utf-8?B?QmYxYUNsUlNTdFFyRWR2QnB4VGpJbWhNeURFdnhyYjVWRytiYjhpMFhOekYx?=
 =?utf-8?B?K2EvSVV3NUhYdjdjTjloWmoxUDFYdnVhbFM5ZTlCUmNvMTRJVTZNUmlFZ2hw?=
 =?utf-8?B?Z1hEZXdzaXFFY1kwdVJDazBnYTBiTDEvdmk5MWhJS3Rxc3dWQy94VFZLSllO?=
 =?utf-8?B?NlNjdmtzaWlvUXhDRTFIMnFMdW5DRkhBc3Q2Mm9iZUMrT0hSZGptSHJWM1o5?=
 =?utf-8?Q?SfO3ukYYppRo/t9/myJq6ePr6GcvwwVA9EyiyDRYEw=3D?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 8f00f804-5ff6-4635-8562-08d9f63837a3
X-MS-Exchange-CrossTenant-AuthSource: BN0PR11MB5744.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Feb 2022 19:19:16.4668
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: HPRKNtStHy610A97Os59BrU1YJKi1x0X0sHmhgfg9vinxY0w3EFO9AKE6wwtHPHkbuCW+uaOlOKhO59ZLtftHYlox7L7hgk2kzsnF6z6DCI=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR11MB1477
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,
        RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE
        autolearn=ham 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-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Jarkko,

On 2/20/2022 10:40 AM, Jarkko Sakkinen wrote:
...
 
> Do you know if it is possible to do EAUG, EMODPR and the do a single
> EACCEPT for both? Just looking at pseudo-code, it looked doable but
> I need to check this.
> 
> I.e. EAUG has this
> 
> EPCM(DS:RCX).BLOCKED := 0;
> EPCM(DS:RCX).PENDING := 1;
> EPCM(DS:RCX).MODIFIED := 0;
> EPCM(DS:RCX).PR := 0;
> (* associate the EPCPAGE with the SECS by storing the SECS identifier of DS:TMP_SECS *)
> Update EPCM(DS:RCX) SECS identifier to reference DS:TMP_SECS identifier;
> (* Set EPCM valid fields *)
> EPCM(DS:RCX).VALID := 1;
> 
> And EMODPR only checks .VALID.

After that check there is also:
IF (EPCM(DS:RCX).PENDING is not 0 or (EPCM(DS:RCX).MODIFIED is not 0) )
    THEN
        RFLAGS.ZF := 1;
        RAX := SGX_PAGE_NOT_MODIFIABLE;
        GOTO DONE;
FI;

Attempting the SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS ioctl() on a recently
added page (EAUG) that has not yet been EACCEPTed is thus expected to fail
with errno of EFAULT (indicating ENCLS[EMODPR] failure) and the returned
structure's result field set to 20 (SGX_PAGE_NOT_MODIFIABLE).

I confirmed this behavior by modifying the "augment" kselftest test by adding
a SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS call between the new memory access and
the EACCEPT.

Reinette