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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 1C57CC433E0 for ; Thu, 4 Feb 2021 03:06:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4F8D64DA1 for ; Thu, 4 Feb 2021 03:06:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232762AbhBDDGl (ORCPT ); Wed, 3 Feb 2021 22:06:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:54926 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232138AbhBDDGk (ORCPT ); Wed, 3 Feb 2021 22:06:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 747AE64E42; Thu, 4 Feb 2021 03:05:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612407960; bh=hmc5VBzB3YO0sZl/LTnIPs8r2hhaZ3cnQLrS3D5Tk1k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uGIJ9q/NWP56+uFCjk3p9604Sdcas36IJjircBYpi2P/W4Yrv3jts3IlOTo7dQhFs Mupr92taEGhC95uh6Iv3WWAsgSf8jUfDAAWV7oJmIUo7Bj4es9PX2503QSu+o+9Ltt NJ1VC/XWrDUqUg/PuFtPrivbfN6O1y+JDlGrW7kcsKsLbTbQOgnZOcZroq1Y7Jr5bM JIi3EiZ/+V5DvmI9pjdWhoVsV58EnZcm5CrdDhQ5DbFBjmg/Flp2VgTJEgYtPywAtQ KjATBPPD2PFvnL4KmCyNJ/xDQTx3XDuBS5rs7Cv40TUn91eNmbZuIGXdR9cN0Leq4c i5WRM8T+VqZiw== Date: Thu, 4 Feb 2021 05:05:52 +0200 From: Jarkko Sakkinen To: Kai Huang Cc: Sean Christopherson , linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org, luto@kernel.org, dave.hansen@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Subject: Re: [RFC PATCH v3 08/27] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Message-ID: References: <20210201184040.646ea9923c2119c205b3378d@intel.com> <20210203134906.78b5265502c65f13bacc5e68@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Thu, Feb 04, 2021 at 03:59:20PM +1300, Kai Huang wrote: > On Thu, 2021-02-04 at 03:39 +0200, Jarkko Sakkinen wrote: > > On Wed, Feb 03, 2021 at 02:59:47PM -0800, Sean Christopherson wrote: > > > On Thu, Feb 04, 2021, Jarkko Sakkinen wrote: > > > > On Wed, Feb 03, 2021 at 01:49:06PM +1300, Kai Huang wrote: > > > > > What working *incorrectly* thing is related to SGX virtualization? The things > > > > > SGX virtualization requires (basically just raw EPC allocation) are all in > > > > > sgx/main.c. > > > > > > > > States: > > > > > > > > A. SGX driver is unsupported. > > > > B. SGX driver is supported and initialized correctly. > > > > C. SGX driver is supported and failed to initialize. > > > > > > > > I just thought that KVM should support SGX when we are either in states A > > > > or B. Even the short summary implies this. It is expected that SGX driver > > > > initializes correctly if it is supported in the first place. If it doesn't, > > > > something is probaly seriously wrong. That is something we don't expect in > > > > a legit system behavior. > > > > > > It's legit behavior, and something we (you?) explicitly want to support. See > > > patch 05, x86/cpu/intel: Allow SGX virtualization without Launch Control support. > > > > What I think would be a sane behavior, would be to allow KVM when > > sgx_drv_init() returns -ENODEV (case A). This happens when LC is > > not enabled: > > > > if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) > > return -ENODEV; > > > > /Jarkko > > I really don't understand what's the difference between A and C. When "SGX driver is > supported and failed to initialize" happens, it just means "SGX driver is > unsupported". If it is not the case, can you explicitly point out what will be the > problem? ret != 0 && ret != -ENODEV /Jarkko