From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933108AbcFGOOM (ORCPT ); Tue, 7 Jun 2016 10:14:12 -0400 Received: from prv-mh.provo.novell.com ([137.65.248.74]:50513 "EHLO prv-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932364AbcFGOOI convert rfc822-to-8bit (ORCPT ); Tue, 7 Jun 2016 10:14:08 -0400 Message-Id: <5756F2CC02000078000F2A64@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.2.0 Date: Tue, 07 Jun 2016 08:14:04 -0600 From: "Jan Beulich" To: "David Vrabel" , "Boris Ostrovsky" , "Konrad Rzeszutek Wilk" , "Juergen Gross" Cc: "xen-devel" , Subject: Re: [PATCH v2 1/2] xen-pciback: return proper values during BAR sizing References: <5756857802000078000F268D@prv-mh.provo.novell.com> <5756864102000078000F269A@prv-mh.provo.novell.com> <5756D4F4.7070802@oracle.com> In-Reply-To: <5756D4F4.7070802@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 07.06.16 at 16:06, wrote: > On 06/07/2016 02:30 AM, Jan Beulich wrote: >> Reads following writes with all address bits set to 1 should return all >> changeable address bits as one, not the BAR size (nor, as was the case >> for the upper half of 64-bit BARs, the high half of the region's end >> address). Presumably this didn't cause any problems so far because >> consumers use the value to calculate the size (usually via val & -val), >> and do nothing else with it. >> >> But also consider the exception here: Unimplemented BARs should always >> return all zeroes. >> >> And finally, the check for whether to return the sizing address on read >> for the ROM BAR should ignore all non-address bits, not just the ROM >> Enable one. > > > Should this go to stable trees as well? Not sure - we had no active reports of problems. The context this was found in did not really have an issue because it was broken. I guess I'll leave this to you maintainers... Jan