From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752071Ab0DMWcP (ORCPT ); Tue, 13 Apr 2010 18:32:15 -0400 Received: from rcsinet12.oracle.com ([148.87.113.124]:62805 "EHLO rcsinet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750854Ab0DMWcN (ORCPT ); Tue, 13 Apr 2010 18:32:13 -0400 Message-ID: <4BC4F03C.1020707@oracle.com> Date: Tue, 13 Apr 2010 15:29:16 -0700 From: Yinghai User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100317 SUSE/3.0.4-1.1.1 Thunderbird/3.0.4 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Bjorn Helgaas , Thomas Gleixner , Ingo Molnar , Andy Isaacson , guenter.roeck@ericsson.com, Linus Torvalds , "linux-pci@vger.kernel.org" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Thomas Renninger Subject: Re: [PATCH -v2 1/2] x86: Reserve [0xa0000, 0x100000] in e820 map References: <20100409223532.GC11130@hexapodia.org> <4BBFB1D8.6090802@oracle.com> <20100410000030.GE11130@hexapodia.org> <4BBFD019.9040405@oracle.com> <20100410014308.GG11130@hexapodia.org> <4BBFD8EF.6020108@oracle.com> <20100410015711.GH11130@hexapodia.org> <4BBFE66C.2040603@oracle.com> <20100412185416.GA19959@hexapodia.org> <4BC375D9.4040503@oracle.com> <20100412200224.GO11130@hexapodia.org> <4BC39F67.4090407@oracle.com> <1271192527.6035.44.camel@dc7800.home> <4BC4DD85.5030203@zytor.com> <4BC4DDEA.60202@oracle.com> <4BC4DFAD.9020600@zytor.com> <4BC4E55B.7000103@oracle.com> <4BC4E8FB.8060802@zytor.com> In-Reply-To: <4BC4E8FB.8060802@zytor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: acsmt355.oracle.com [141.146.40.155] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090202.4BC4F0C8.0140:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/13/2010 02:58 PM, H. Peter Anvin wrote: > On 04/13/2010 02:42 PM, Yinghai wrote: >> On 04/13/2010 02:18 PM, H. Peter Anvin wrote: >>> On 04/13/2010 02:11 PM, Yinghai wrote: >>>>> >>>>> I guess the real question (which I haven't looked at myself) is if the >>>>> E820_RESERVED -> BUSY will cause an explicitly assigned BAR from being >>>>> moved. That's bad, not so much for this particular range, but from BARs >>>>> which may be assigned by SMM. Hacking that up in a simulator >>>>> (Qemu/Bochs) and testing it is probably on the to do list... >>>> >>>> no, if some device BAR fall in that range, it should still use that range, and will not be relocated. >>>> >>>> will update the change log. >>>> >>> >>> Good, that's what we want. >> >> the driver for that device later can not use pci_request_region(). because that region is BUSY already. >> > > That's not good (in general - for devices in this particular range it's > not such a big deal, but it is potentially really bad for devices marked > reserved for them not to be moved.) > > We have talked about a need to resolve this before. current code for mmio that is just below 4g, if some PCI BAR use that range, and those range is falling into E820_RESERVED, those range still can be claimed, but driver can not use pci_request_region() later. So We still 1. rely that BIOS does not reserve the [0xa0000, 0xe0000) 2. kernel only reserve the range when we make sure these is legacy device on that range. YH