From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp05.au.ibm.com ([202.81.31.147]:60815 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932832AbcCQLbP (ORCPT ); Thu, 17 Mar 2016 07:31:15 -0400 Received: from localhost by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 17 Mar 2016 21:31:12 +1000 Subject: Re: [RFC PATCH v4 5/7] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive To: Alex Williamson References: <1457336918-3893-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1457336918-3893-6-git-send-email-xyjxie@linux.vnet.ibm.com> <20160316103034.48666ae0@t450s.home> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, bhelgaas@google.com, corbet@lwn.net, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com From: Yongji Xie Message-ID: <56EA9532.2050902@linux.vnet.ibm.com> Date: Thu, 17 Mar 2016 19:29:54 +0800 MIME-Version: 1.0 In-Reply-To: <20160316103034.48666ae0@t450s.home> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 2016/3/17 0:30, Alex Williamson wrote: > On Mon, 7 Mar 2016 15:48:36 +0800 > Yongji Xie wrote: > >> Current vfio-pci implementation disallows to mmap >> sub-page(size < PAGE_SIZE) MMIO BARs because these BARs' mmio >> page may be shared with other BARs. >> >> But we should allow to mmap these sub-page MMIO BARs if PCI >> resource allocator can make sure these BARs' mmio page will >> not be shared with other BARs. >> >> Signed-off-by: Yongji Xie >> --- >> drivers/vfio/pci/vfio_pci.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c >> index 1ce1d36..49d7a69 100644 >> --- a/drivers/vfio/pci/vfio_pci.c >> +++ b/drivers/vfio/pci/vfio_pci.c >> @@ -589,7 +589,8 @@ static long vfio_pci_ioctl(void *device_data, >> VFIO_REGION_INFO_FLAG_WRITE; >> if (IS_ENABLED(CONFIG_VFIO_PCI_MMAP) && >> pci_resource_flags(pdev, info.index) & >> - IORESOURCE_MEM && info.size >= PAGE_SIZE) { >> + IORESOURCE_MEM && !pci_resources_share_page(pdev, >> + info.index)) { > this would be a preferable line wrap: > > IORESOURCE_MEM && > !pci_resources_share_page(pdev, info.index)) { OK. I'll fix it. Thanks, Yongji Xie