From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp03.in.ibm.com ([125.16.236.3]:44238 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754889AbcAOHIE (ORCPT ); Fri, 15 Jan 2016 02:08:04 -0500 Received: from localhost by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 15 Jan 2016 12:38:01 +0530 From: Yongji Xie To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org Cc: bhelgaas@google.com, corbet@lwn.net, aik@ozlabs.ru, alex.williamson@redhat.com, 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, Yongji Xie Subject: [RFC PATCH v3 2/5] vfio-pci: Allow to mmap sub-page MMIO BARs if the mmio page is exclusive Date: Fri, 15 Jan 2016 15:06:11 +0800 Message-Id: <1452841574-2781-3-git-send-email-xyjxie@linux.vnet.ibm.com> In-Reply-To: <1452841574-2781-1-git-send-email-xyjxie@linux.vnet.ibm.com> References: <1452841574-2781-1-git-send-email-xyjxie@linux.vnet.ibm.com> Sender: linux-pci-owner@vger.kernel.org List-ID: 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 7e9f497..11fd0f0 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -552,7 +552,8 @@ 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)) { info.flags |= VFIO_REGION_INFO_FLAG_MMAP; if (info.index == vdev->msix_bar) { ret = msix_sparse_mmap_cap(vdev, &caps); @@ -954,6 +955,10 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma) return -EINVAL; phys_len = pci_resource_len(pdev, index); + + if (!pci_resources_share_page(pdev, index)) + phys_len = PAGE_ALIGN(phys_len); + req_len = vma->vm_end - vma->vm_start; pgoff = vma->vm_pgoff & ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1); -- 1.7.9.5