From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:18037 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161156Ab3DKR5a (ORCPT ); Thu, 11 Apr 2013 13:57:30 -0400 Message-ID: <1365703048.26525.8.camel@ul30vt.home> Subject: Re: [Question] Failed to access the BAR MMIO space of PCI device From: Alex Williamson To: zhengfei Cc: linux-pci@vger.kernel.org Date: Thu, 11 Apr 2013 11:57:28 -0600 In-Reply-To: References: <1365431000.16420.11.camel@bling.home> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: On Thu, 2013-04-11 at 17:15 +0000, zhengfei wrote: > Alex Williamson redhat.com> writes: > > > > > On Sun, 2013-04-07 at 19:19 +0000, zhengfei wrote: > > > Hi, > > > > > > I'm writing a driver for a SR-IOV device on the PCI bus. My architecture > is > > > a 64-bit X86 of intel Sandy bridge. > > > > > > In my device driver, I want to configure the device to transfer data > to/from > > > X86.I get the the device BAR MMIO base address with the command "lspci - > s > > > 04:00.03 -xxx" in the guest os(kvm). > > > But after I ioremap() that MMIO base address,I failed to access the BAR > MMIO > > > space in the guest os(kvm). > > > > > > Is there a function which show mapping between the real PCI address > stored in > > > the BAR and the emulated address stored in the BAR? > > > > Is this a userspace driver or a kernel driver? I can't figure out why > > you would use lspci to get a static BAR address, then use ioremap() to > > map it. If it's a kernel driver, the sequence you want is something > > like: > > > > pci_enable_device > > pci_request_selected_regions > > pci_iomap > > > > Thanks, > > Alex > > > > > > It is a userspace driver on guest os.To be simply,I got the BAR0 > address(gpa) on guest os,but I failed to access real BAR0 MMIO address space > of the device with the gpa.So what can I do next? and in which source code > file,could I find the procedure of mapping the real BAR address space（hpa) > to gpa? The guest doesn't have access to the hpa, nor should it need it. To map BAR0 from guest userspace mmap /sys/bus/pci/devices/xxxx:xx:xx.x/resource0. Thanks, Alex