From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936103Ab3DRP7z (ORCPT ); Thu, 18 Apr 2013 11:59:55 -0400 Received: from inca-roads.misterjones.org ([213.251.177.50]:49486 "EHLO inca-roads.misterjones.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935794Ab3DRP7y (ORCPT ); Thu, 18 Apr 2013 11:59:54 -0400 To: Christopher Covington Subject: Re: [RFC] arm64: Early printk support for virtio-mmio console devices. X-PHP-Originating-Script: 0:func.inc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Date: Thu, 18 Apr 2013 17:59:43 +0200 From: Marc Zyngier Cc: PranavkumarSawargaonkar , , Anup Patel , , , , , Organization: ARM Ltd In-Reply-To: <51701084.5050706@codeaurora.org> References: <1366264344-28025-1-git-send-email-pranavkumar@linaro.org> <51701084.5050706@codeaurora.org> Message-ID: <217a4f2dd017af16204391012751e9f9@localhost> User-Agent: RoundCube Webmail/0.3.1 X-SA-Exim-Connect-IP: X-SA-Exim-Rcpt-To: cov@codeaurora.org, pranavkumar@linaro.org, linaro-kernel@lists.linaro.org, anup.patel@linaro.org, patches@linaro.org, rusty@rustcorp.com.au, linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: marc.zyngier@arm.com X-SA-Exim-Scanned: No (on inca-roads.misterjones.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 18 Apr 2013 11:25:56 -0400, Christopher Covington wrote: > Hi Pranavkumar, > > On 04/18/2013 01:52 AM, PranavkumarSawargaonkar wrote: >> From: Pranavkumar Sawargaonkar >> >> This patch implements early printk support for virtio-mmio console >> devices >> without using any hypercalls. > > Is it possible that using DCC might be an easier solution? You would end up with the exact same problem as with a hypercall based solution: once you're in the hypervisor, what do you do with the data? You end up having to invent another channel to forward it down to your platform emulation in order to have it printed where the user expects it. Using a MMIO based solution is probably the best solution, as it uses the existing infrastructure. M. -- Fast, cheap, reliable. Pick two.