From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752602AbdKHNqu (ORCPT ); Wed, 8 Nov 2017 08:46:50 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:49596 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752376AbdKHNqt (ORCPT ); Wed, 8 Nov 2017 08:46:49 -0500 Subject: Re: [PATCH 0/3] x86/xen: support booting PVH guest via standard boot path To: Juergen Gross , linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org References: <20171108090739.26491-1-jgross@suse.com> <875b3992-c797-b109-6eb2-819e52811eca@oracle.com> <0d04d8cd-41e6-31bd-f5e6-8d1f6fd60efb@suse.com> Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, pbonzini@redhat.com, rkrcmar@redhat.com, rjw@rjwysocki.net, len.brown@intel.com, pavel@ucw.cz From: Boris Ostrovsky Message-ID: <335b8767-dae8-8f85-fbe5-3f10a1af52c8@oracle.com> Date: Wed, 8 Nov 2017 08:47:54 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <0d04d8cd-41e6-31bd-f5e6-8d1f6fd60efb@suse.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: userv0021.oracle.com [156.151.31.71] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/08/2017 08:40 AM, Juergen Gross wrote: > On 08/11/17 14:37, Boris Ostrovsky wrote: >> On 11/08/2017 04:07 AM, Juergen Gross wrote: >>> Booting a Xen PVH guest requires a special boot entry as it is >>> mandatory to setup some Xen-specific interfaces rather early. When grub >>> or OVMF are used as boot loaders, however, those will fill the boot >>> parameters in zeropage and there is no longer a need to do something >>> PVH specific in the early boot path. >>> >>> This patch series adds support for that scenario by identifying PVH >>> environment and doing the required init steps via Xen hooks instead of >>> using a dedicated boot entry. >>> >>> The dedicated entry is still needed for support of Dom0 running in PVH >>> mode as in this case there is no grub or OVMF involved for filling in >>> the boot parameters. >> We are going to continue supporting direct boot of unprivileged guests >> too so this entry point will be needed not for dom0 only. > Sure, but using e.g. grub in this case would be an alternative. For Dom0 > this alternative isn't existing. So this entry is mandatory, not a "nice > to have". Right, I was just pointing out that the way the message is phrased makes it sounds (to me at least) as if dom0 is the only reason for the dedicated entry point. -boris