Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754053Ab3EAGx6 (ORCPT ); Wed, 1 May 2013 02:53:58 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:56300 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753426Ab3EAGxu (ORCPT ); Wed, 1 May 2013 02:53:50 -0400 MIME-Version: 1.0 X-Originating-IP: [14.97.190.184] In-Reply-To: <87sj27xxjr.fsf@rustcorp.com.au> References: <1366974299-17877-1-git-send-email-pranavkumar@linaro.org> <87obcyc9sh.fsf@rustcorp.com.au> <336C59AA-D5D7-472E-A8DA-EEB413DD6C68@suse.de> <87sj27xxjr.fsf@rustcorp.com.au> Date: Wed, 1 May 2013 12:23:49 +0530 Message-ID: Subject: Re: [PATCH 0/2] Early printk support for virtio console devices. From: Anup Patel To: Rusty Russell Cc: Alexander Graf , Pranavkumar Sawargaonkar , "linaro-kernel@lists.linaro.org" , "patches@linaro.org" , "linux-kernel@vger.kernel.org List" , "kvmarm@lists.cs.columbia.edu" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1745 Lines: 48 On Wed, May 1, 2013 at 7:37 AM, Rusty Russell wrote: > Alexander Graf writes: >> There are not device specific registers in >> virtio-console. Virtio-console lives behind a virtio bus which doesn't >> know what these registers are. > > You're not going to make coherent arguments without reading that actual > patch we're discussing. And you're going to just waste everyone else's > time. > >> Even if you shove it into config space, > > Which is what the patch does... > >> it'd be broken because config access happens without intercepts on >> some platforms. > > But people keep assuming it, which is one reason virtio_ccw switched > from passive lguest-style config to active. Only lguest and the old kvm > virtio use it, and lguest can change. > > An emergency output is a reasonable idea, and this is a reasonable > implementation. The question is practical: will it be used? Because we > don't implement reasonable ideas which aren't going to be used. We are already using it for Guest bring-up on APM ARM64 board using KVMTOOL and so far it has been really helpful in debugging KVM ARM64 guest issues. Also, this is a very useful debugging method for Guest bring-up on other architectures supported by KVM and other Hypervisors that support VirtIO. > > Cheers, > Rusty. > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm Regards, Anup -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/