From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6A8EC4741F for ; Mon, 28 Sep 2020 15:54:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9D0F2100A for ; Mon, 28 Sep 2020 15:54:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ssx9hM2O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726684AbgI1Pyi (ORCPT ); Mon, 28 Sep 2020 11:54:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726565AbgI1Pyi (ORCPT ); Mon, 28 Sep 2020 11:54:38 -0400 Received: from mail-il1-x143.google.com (mail-il1-x143.google.com [IPv6:2607:f8b0:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3902FC061755; Mon, 28 Sep 2020 08:54:38 -0700 (PDT) Received: by mail-il1-x143.google.com with SMTP id h2so1728678ilo.12; Mon, 28 Sep 2020 08:54:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wVGPSPUovgc0Y23DJShhn11Uz/FVeEYO+SSSJn1LJ3o=; b=Ssx9hM2ObzgBkZv/NTryYKHFTVD0EaOXq2rFryyfgxQJSsu44+gMlEl3enPTKDucrV B3dBgmd62wss8RyxXD+goGRHFm4U0WT/a22l+4uEnw1Qn855+1StCY7YUvaWD+c/UWEn poM+GYoBbO90chF+z0q6kzvMlcaAGp5oIF6wqPWXIVQMFD0RoRF5+VT/36X63+hlnOm9 NsfzRRfAmqrC5DfC05tHNVqL+NCpZm8LgdUKsWNnBOoYUX65mReVtAfdlZFgAVTKbJEU biPfnvTUF1JjwjpvS6WsehAiYdmr9zU6Bz3sYbVRKFdo6U1H6RNh8kU6xhPdV+ydi+lo PxKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wVGPSPUovgc0Y23DJShhn11Uz/FVeEYO+SSSJn1LJ3o=; b=itvMuNePMTQt4k3JQHDQxFpr5sl0qViL6qE3mQBkhI22s2K52BwZn6w6FTmdDQASSy bugSpLo7uIrfBusKnRgPaEpmo1nPsJJD9xitUx6AKSdqVopMUJPVure1406jBhDPTFCa Z6l1WSj5gRvUzGJUQULZUeXlBYh0LwXaa6lnqwCHq9wudwHqr6bTKuxRJMgDPdYJ3+xK QsLrk7y3TYKAwGPfrT7phxuAzLJJg3pkP+uBEeN8sH/JS7DI5SQ5rGWzevVy9ubBNc4j m5NoDhcjrcZ5sxBJuNm8nnVZdl8+QDlEfqTY6ivpZF8YGCCt83UqYDfEPaw94rdb/+02 AaAg== X-Gm-Message-State: AOAM530Fc65QdlxVei+viRY8OvIM+hRxDmhl7kSO2UZLnLGTFs6bF4Ca OCIBa1SQu5zqQoPMbpdlq3RgczUOPonYTg8TY9U= X-Google-Smtp-Source: ABdhPJzBbYtkYsjjz2crHkvXucIQCF2Lv8kuXTp2BGrwoD5/FzL7ABH+JNxVVB2Cif6HZbIt1e+pbs0C1wtTcVe4TG8= X-Received: by 2002:a05:6e02:d06:: with SMTP id g6mr1716472ilj.151.1601308477565; Mon, 28 Sep 2020 08:54:37 -0700 (PDT) MIME-Version: 1.0 References: <20200915112842.897265-1-jarkko.sakkinen@linux.intel.com> <20200915112842.897265-22-jarkko.sakkinen@linux.intel.com> <721ca14e-21df-3df1-7bef-0b00d0ff90c3@citrix.com> In-Reply-To: From: "H.J. Lu" Date: Mon, 28 Sep 2020 08:54:01 -0700 Message-ID: Subject: Re: [PATCH v38 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call To: "Yu, Yu-cheng" Cc: Andrew Cooper , Jarkko Sakkinen , "the arch/x86 maintainers" , linux-sgx@vger.kernel.org, LKML , Sean Christopherson , Andy Lutomirski , Jethro Beekman , Cedric Xing , Andrew Morton , andriy.shevchenko@linux.intel.com, asapek@google.com, Borislav Petkov , chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, Dave Hansen , "Huang, Haitao" , josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, Christian Ludloff , Andy Lutomirski , nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, Thomas Gleixner , yaozhangx@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 28, 2020 at 8:43 AM Yu, Yu-cheng wrote: > > On 9/25/2020 11:23 AM, Andrew Cooper wrote: > > On 15/09/2020 12:28, Jarkko Sakkinen wrote: > >> diff --git a/arch/x86/entry/vdso/vsgx_enter_enclave.S b/arch/x86/entry/vdso/vsgx_enter_enclave.S > >> new file mode 100644 > >> index 000000000000..adbd59d41517 > >> --- /dev/null > >> +++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S > >> @@ -0,0 +1,157 @@ > >> +SYM_FUNC_START(__vdso_sgx_enter_enclave) > >> > >> +.Lretpoline: > >> + call 2f > >> +1: pause > >> + lfence > >> + jmp 1b > >> +2: mov %rax, (%rsp) > >> + ret > > > > I hate to throw further spanners in the work, but this is not compatible > > with CET, and the user shadow stack work in progress. > > Hi Jarkko, > > These 1: and 2: targets are reached only from these few lines? If they > are direct call/jmp targets, I think it is OK in terms of CET. If they > are reached from an instruction like "jmp *%rax", then we need to put in > an "endbr64". > This also isn't compatible with shadow stack. -- H.J.