Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751639Ab3HSXCw (ORCPT ); Mon, 19 Aug 2013 19:02:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35291 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751607Ab3HSXCt (ORCPT ); Mon, 19 Aug 2013 19:02:49 -0400 Message-ID: <1376953365.2657.36.camel@ul30vt.home> Subject: Re: [PATCH] vfio-pci: PCI hot reset interface From: Alex Williamson To: Benjamin Herrenschmidt Cc: Bjorn Helgaas , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , Alexander Viro , linux-fsdevel Date: Mon, 19 Aug 2013 17:02:45 -0600 In-Reply-To: <1376952280.25016.87.camel@pasglop> References: <20130814200845.21923.64284.stgit@bling.home> <1376521578.13642.65.camel@ul30vt.home> <1376937682.2657.15.camel@ul30vt.home> <1376943632.2657.25.camel@ul30vt.home> <1376952280.25016.87.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1396 Lines: 31 On Tue, 2013-08-20 at 08:44 +1000, Benjamin Herrenschmidt wrote: > On Mon, 2013-08-19 at 14:20 -0600, Alex Williamson wrote: > > I try to handle the slot as opaque, only caring that the slot pointer > > matches, so I think our implementation is ok... so long as we only get > > one driver claiming to manage a slot, but that's not a vfio problem ;) > > Thanks, > > By why bother with slots ? Why do you even think about slots in that > context ? slots are a badly defined thing in our current PCI stack, > pretty much intricated with hotplug. I don't see why the reset semantics > would be tied to slots at all. See my other reply, hotplug presence detection and secondary bus resets don't just work. > The only case where it *might* make some sense (and even then ...) is if > you want to start exposing slot power control and PERST but that would > imply a pile of platform specific gunk anyway. But that platform specific gunk can be hidden away in the hotplug controller. We just need to be able to ask if it can reset a slot and tell it to do it. If it happens via a slot power control or a secondary bus reset, do we care? Thanks, Alex -- 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/