From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:59712 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753387AbbLRN5m (ORCPT ); Fri, 18 Dec 2015 08:57:42 -0500 Subject: Re: [PATCH 2/2] pci: Update VPD size with correct length To: Alexander Duyck References: <1450427719-29619-1-git-send-email-hare@suse.de> <1450427719-29619-3-git-send-email-hare@suse.de> Cc: Bjorn Helgaas , Michal Kubecek , "Shane M. Seymour" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Bjorn Helgaas From: Hannes Reinecke Message-ID: <567410D3.7030909@suse.de> Date: Fri, 18 Dec 2015 14:57:39 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 12/18/2015 02:49 PM, Alexander Duyck wrote: > On Fri, Dec 18, 2015 at 12:35 AM, Hannes Reinecke wrote: >> PCI-2.2 VPD entries have a maximum size of 32k, but might actually >> be smaller than that. To figure out the actual size one has to read >> the VPD area until the 'end marker' is reached. >> Trying to read VPD data beyond that marker results in 'interesting' >> effects, from simple read errors to crashing the card. And to make >> matters worse not every PCI card implements this properly, leaving >> us with no 'end' marker or even completely invalid data. >> This path modifies the size of the VPD attribute to the available >> size, or set it to '0' if no valid data could be read. > > This isn't what I had in mind. There is no need to add an f0 version > of the size function. The size for all functions other than function > 0 when the F0 flag is set is 0. We aren't going to be reading their > VPD, we only read the VPD region of function 0. > Ah. (I'm a bit confused about the proposed action for VPD other than function 0). So the idea here is to _disallow_ access to VPDs from functions other than '0' unless these functions have different PCI IDs? Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)