Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755478AbbLaIwb (ORCPT ); Thu, 31 Dec 2015 03:52:31 -0500 Received: from e28smtp05.in.ibm.com ([125.16.236.5]:45101 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755350AbbLaIwR (ORCPT ); Thu, 31 Dec 2015 03:52:17 -0500 X-IBM-Helo: d28dlp02.in.ibm.com X-IBM-MailFrom: xyjxie@linux.vnet.ibm.com X-IBM-RcptTo: kvm@vger.kernel.org;linux-doc@vger.kernel.org;linux-kernel@vger.kernel.org;linux-pci@vger.kernel.org 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 v2 3/3] vfio-pci: Allow to mmap MSI-X table if EEH is supported Date: Thu, 31 Dec 2015 16:50:44 +0800 Message-Id: <1451551844-11732-4-git-send-email-xyjxie@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1451551844-11732-1-git-send-email-xyjxie@linux.vnet.ibm.com> References: <1451551844-11732-1-git-send-email-xyjxie@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15123108-0017-0000-0000-0000093ECBC9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2460 Lines: 69 Current vfio-pci implementation disallows to mmap MSI-X table in case that user get to touch this directly. However, EEH mechanism can ensure that a given pci device can only shoot the MSIs assigned for its PE. So we think it's safe to expose the MSI-X table to userspace because the exposed MSI-X table can't be used to do harm to other memory space. And with MSI-X table mmapped, some performance issues which are caused when PCI adapters have critical registers in the same page as the MSI-X table also can be resolved. So this patch adds a Kconfig option, VFIO_PCI_MMAP_MSIX, to support for mmapping MSI-X table. Signed-off-by: Yongji Xie --- drivers/vfio/pci/Kconfig | 4 ++++ drivers/vfio/pci/vfio_pci.c | 6 ++++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig index 02912f1..67b0a2c 100644 --- a/drivers/vfio/pci/Kconfig +++ b/drivers/vfio/pci/Kconfig @@ -23,6 +23,10 @@ config VFIO_PCI_MMAP depends on VFIO_PCI def_bool y if !S390 +config VFIO_PCI_MMAP_MSIX + depends on VFIO_PCI_MMAP + def_bool y if EEH + config VFIO_PCI_INTX depends on VFIO_PCI def_bool y if !S390 diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 09b3805..d536985 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -555,7 +555,8 @@ static long vfio_pci_ioctl(void *device_data, IORESOURCE_MEM && (info.size >= PAGE_SIZE || pci_resource_page_aligned)) { info.flags |= VFIO_REGION_INFO_FLAG_MMAP; - if (info.index == vdev->msix_bar) { + if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP_MSIX) && + info.index == vdev->msix_bar) { ret = msix_sparse_mmap_cap(vdev, &caps); if (ret) return ret; @@ -967,7 +968,8 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma) if (phys_len < PAGE_SIZE || req_start + req_len > phys_len) return -EINVAL; - if (index == vdev->msix_bar) { + if (!IS_ENABLED(CONFIG_VFIO_PCI_MMAP_MSIX) && + index == vdev->msix_bar) { /* * Disallow mmaps overlapping the MSI-X table; users don't * get to touch this directly. We could find somewhere -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/