From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753847AbdK2I7T (ORCPT ); Wed, 29 Nov 2017 03:59:19 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:44017 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753828AbdK2I7R (ORCPT ); Wed, 29 Nov 2017 03:59:17 -0500 X-Google-Smtp-Source: AGs4zMay6m5n072Xy9xItOH1q6dyzsC9B4zqsq97wgmdaeNImYXHbE4q/+zQF1zwedsFGPErrg2xIA== Subject: Re: [RFC PATCH] KVM: x86: Allow Qemu/KVM to use PVH entry point To: Maran Wilson , boris.ostrovsky@oracle.com, jgross@suse.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, roger.pau@citrix.com, rkrcmar@redhat.com, JBeulich@suse.com, andrew.cooper3@citrix.com, kvm@vger.kernel.org References: <1511897682-32060-1-git-send-email-maran.wilson@oracle.com> From: Paolo Bonzini Message-ID: Date: Wed, 29 Nov 2017 09:59:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1511897682-32060-1-git-send-email-maran.wilson@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/11/2017 20:34, Maran Wilson wrote: > For certain applications it is desirable to rapidly boot a KVM virtual > machine. In cases where legacy hardware and software support within the > guest is not needed, Qemu should be able to boot directly into the > uncompressed Linux kernel binary without the need to run firmware. > > There already exists an ABI to allow this for Xen PVH guests and the ABI is > supported by Linux and FreeBSD: > > https://xenbits.xen.org/docs/unstable/misc/hvmlite.html > > This PoC patch enables Qemu to use that same entry point for booting KVM > guests. Nice! So QEMU would parse the ELF file just like for multiboot, find the ELF note, and then prepare an hvmlite boot info struct instead of the multiboot one? There would then be a new option ROM, very similar to multiboot.S. Thanks, Paolo