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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 E6D19C433E9 for ; Mon, 1 Mar 2021 17:36:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BAEF164F2B for ; Mon, 1 Mar 2021 17:36:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237951AbhCARf7 (ORCPT ); Mon, 1 Mar 2021 12:35:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238090AbhCARam (ORCPT ); Mon, 1 Mar 2021 12:30:42 -0500 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3D60C06178A for ; Mon, 1 Mar 2021 09:29:55 -0800 (PST) Received: by mail-pj1-x1036.google.com with SMTP id i14so10121371pjz.4 for ; Mon, 01 Mar 2021 09:29:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=dsBZmo7yHiiMQ5Fonyw4uCM2dBJFr4DMbpHeKPUN97w=; b=VHmr5H/HHBNEIniUAlXBwTWXqsPNhR4dVZFxuWdraxH3/sVGt/Mk2LJ7gU2J7OhNbk NbOtCF2MU+tUkoymahODmgPtSlN22JITLVnra7OdLWuX9irDfljX34IWWSt/8/VttCLR DpNTezrcV2vDUhY+qsXGKwWCPCQMm60H1JtBUuPcqzYVkY6hhfF+o+7AARuuLooepwue zQGYX4IyEpVFFvFgSkXKGJ5fTHUTiAuMATxrFec12zLski1GrFPa1PWB1zvp0XruULFP hsuZeBiONLsCSASL3dJNYZ3G4inRDB4O8ebFsxfAbNxNFvwFq4mnD8ifwA2Gn3pDPP0m 8a/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=dsBZmo7yHiiMQ5Fonyw4uCM2dBJFr4DMbpHeKPUN97w=; b=AwTSLkkAdomev0FQx8A/XFiJrDrmqQVq9JvR0UU2HsUQlkpOFWKJLHkSv1rMF6Of+e 7sI9GH2SBNRQ4LU2YsNkl7/BVbn0E13Zi2O8BpHbNvZ6ZZ8Ogs4L6om8x1DxwNhTfR/0 6WuJkstH0oK2CECzn4cGAO0Uka/6qs28wqw+ajAh+rBetOzmwPyIG1qXeHe04UXQkCb6 RbWfMN0m7/0nWggJqFyZAhnC7VoqtXEvtN8ulWApz77eWDkkUdsdu76XlaRgDR5dqVwF NDyxhr1myodprV/5IRu/8/o6Z2vzN4VbeqAyosVw4FTh/Jh/VC+8pxVeK870cxTb4pa5 V0ug== X-Gm-Message-State: AOAM533tS/CTHzQqQokWXdK0cuIH60FpA4Ly1fRdnlRlFsAcq+8ijxil PgGB/vtJWjrQXRevganGe+NbLw== X-Google-Smtp-Source: ABdhPJxh/vRQVuNDLKJNR2CEhMj6qkhFIK/a7szLZE7YY41foVpV1i/0wP9iTRQYyLOibfWjazkjrQ== X-Received: by 2002:a17:90a:67ca:: with SMTP id g10mr18209260pjm.166.1614619794419; Mon, 01 Mar 2021 09:29:54 -0800 (PST) Received: from google.com ([2620:15c:f:10:5d06:6d3c:7b9:20c9]) by smtp.gmail.com with ESMTPSA id s16sm18604412pfs.39.2021.03.01.09.29.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Mar 2021 09:29:53 -0800 (PST) Date: Mon, 1 Mar 2021 09:29:46 -0800 From: Sean Christopherson To: Kai Huang Cc: kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, jarkko@kernel.org, luto@kernel.org, dave.hansen@intel.com, rick.p.edgecombe@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Subject: Re: [PATCH 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Message-ID: References: <9c2c83ccc7324390bfb302bd327d9236b890c679.1614590788.git.kai.huang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c2c83ccc7324390bfb302bd327d9236b890c679.1614590788.git.kai.huang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Mar 01, 2021, Kai Huang wrote: > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index 7449ef33f081..a7dc86e87a09 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -381,6 +381,26 @@ const struct vm_operations_struct sgx_vm_ops = { > .access = sgx_vma_access, > }; > > +static void sgx_encl_free_epc_page(struct sgx_epc_page *epc_page) > +{ > + int ret; > + > + WARN_ON_ONCE(epc_page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED); > + > + ret = __eremove(sgx_get_epc_virt_addr(epc_page)); > + if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret)) { This can be ENCLS_WARN, especially if you're printing a separate error message about leaking the page. That being said, I'm not sure a seperate error message is a good idea. If other stuff gets dumped to the kernel log between the WARN and the pr_err_once(), it may not be clear to admins that the two events are directly connected. It's even possible the prints could come from two different CPUs. Why not dump a short blurb in the WARN itself? The error message can be thrown in a define if the line length is too obnoxious (it's ~109 chars if embedded directly). #define EREMOVE_ERROR_MESSAGE \ "EREMOVE returned %d (0x%x). EPC page leaked, reboot recommended." if (WARN_ONCE(ret, EREMOVE_ERROR_MESSAGE, ret, ret)) > + /* > + * Give a message to remind EPC page is leaked, and requires > + * machine reboot to get leaked pages back. This can be improved > + * in the future by adding stats of leaked pages, etc. > + */ > + pr_err_once("EPC page is leaked. Require machine reboot to get leaked pages back.\n"); > + return; > + } > + > + sgx_free_epc_page(epc_page); > +} > + > /** > * sgx_encl_release - Destroy an enclave instance > * @kref: address of a kref inside &sgx_encl