From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933482AbcA0PGz (ORCPT ); Wed, 27 Jan 2016 10:06:55 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:34009 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933278AbcA0PGy (ORCPT ); Wed, 27 Jan 2016 10:06:54 -0500 Subject: Re: [Xen-devel] [PATCH v1 04/12] xen/hvmlite: Bootstrap HVMlite guest To: David Vrabel , Konrad Rzeszutek Wilk , "Luis R. Rodriguez" References: <56A2C99A.2050701@citrix.com> <56A39300.8050802@citrix.com> <20160125221920.GG20964@wotan.suse.de> <56A6A7C6.8060906@oracle.com> <20160126203023.GI20964@wotan.suse.de> <56A7EA6A.2030502@oracle.com> <20160127000435.GK20964@wotan.suse.de> <20160127144240.GB552@char.us.oracle.com> <56A8D93C.6040304@citrix.com> Cc: Juergen Gross , Jeremy Fitzhardinge , Rusty Russell , Andrew Cooper , X86 ML , "linux-kernel@vger.kernel.org" , Andy Lutomirski , "H. Peter Anvin" , xen-devel@lists.xenproject.org, Borislav Petkov , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= From: Boris Ostrovsky Message-ID: <56A8DCFD.6040603@oracle.com> Date: Wed, 27 Jan 2016 10:06:37 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <56A8D93C.6040304@citrix.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/27/2016 09:50 AM, David Vrabel wrote: > On 27/01/16 14:42, Konrad Rzeszutek Wilk wrote: >> On Tue, Jan 26, 2016 at 08:54:56PM -0800, Luis R. Rodriguez wrote: >>> On Jan 26, 2016 6:16 PM, "Luis R. Rodriguez" wrote: >>>> On Tue, Jan 26, 2016 at 4:04 PM, Luis R. Rodriguez >>> wrote: >>>>> You go: >>>>> >>>>> hvmlite_start_xen() --> >>>>> HVM stub >>>>> startup_64() | (startup_32() >>>> Hrm, does HVMlite work well with load_ucode_bsp(), note the patches to >>>> rebrand pv_enabled() to pv_legacy() or whatever, this PV type will not >>>> be legacy or crap / old, so we'd need a way to catch it if we should >>>> not use that code for this PV type. This begs the question, are you >>>> also sure other callers in startup_32() or startup_64() might be OK as >>>> well where previously guarded with pv_enabled() ? >>> Actually this call can't be used, and if early code used it prior to >>> setup_arch() it'd be a bug as its only properly set until later. Vetting >>> for correctness of all code call is still required though and perhaps we do >>> need something to catch now this PV type on early code such as this one if >>> we don't want it. From what I've gathered before on other bsp ucode we >>> don't want ucode loaded for PV guest types through these mechanisms. >> It may help to not think of PVH/hvmlite as PV. It really is HVM with a lot >> of emulated devices removed. >> >> How does early microcode work on EFI? Does the EFI stub code have an early >> microcode loading code ? > Surely the interesting comparison here is how is (early) microcode > loading disabled in KVM guests? We should use the same mechanism for > HVMlite guests. Why would we ever want to have a guest load microcode during boot? I can see how a (privileged) guest may want to load microcode from a shell (via microcode driver). -boris