From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752201AbcF3Kxx (ORCPT ); Thu, 30 Jun 2016 06:53:53 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:20492 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752151AbcF3Kxu (ORCPT ); Thu, 30 Jun 2016 06:53:50 -0400 X-IBM-Helo: d28dlp03.in.ibm.com X-IBM-MailFrom: xyjxie@linux.vnet.ibm.com X-IBM-RcptTo: linux-doc@vger.kernel.org;linux-kernel@vger.kernel.org;linux-pci@vger.kernel.org From: Yongji Xie To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org Cc: bhelgaas@google.com, alex.williamson@redhat.com, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, corbet@lwn.net, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, gwshan@linux.vnet.ibm.com Subject: [PATCH v3 6/7] PCI: Add support for enforcing all MMIO BARs to be page aligned Date: Thu, 30 Jun 2016 18:53:12 +0800 X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1467283993-3185-1-git-send-email-xyjxie@linux.vnet.ibm.com> References: <1467283993-3185-1-git-send-email-xyjxie@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16063010-0048-0000-0000-000002ACC1ED X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16063010-0049-0000-0000-00000D74CCDF Message-Id: <1467283993-3185-7-git-send-email-xyjxie@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-30_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606300103 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When vfio passthrough a PCI device of which MMIO BARs are smaller than PAGE_SIZE, guest will not handle the mmio accesses to the BARs which leads to mmio emulations in host. This is because vfio will not allow to passthrough one BAR's mmio page which may be shared with other BARs. Otherwise, there will be a backdoor that guest can use to access BARs of other guest. To solve this issue, this patch modifies resource_alignment to support syntax where multiple devices get the same alignment. So we can use something like "pci=resource_alignment=*:*:*.*:noresize" to enforce the alignment of all MMIO BARs to be at least PAGE_SIZE so that one BAR's mmio page would not be shared with other BARs. Signed-off-by: Yongji Xie --- Documentation/kernel-parameters.txt | 2 ++ drivers/pci/pci.c | 60 ++++++++++++++++++++++++++++------- 2 files changed, 51 insertions(+), 11 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index c4802f5..cb09503 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3003,6 +3003,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. aligned memory resources. If is not specified, PAGE_SIZE is used as alignment. + , , and can be set to + "*" which means match all values. PCI-PCI bridge can be specified, if resource windows need to be expanded. noresize: Don't change the resources' sizes when diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 1d80a94..2e15ac8 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4759,6 +4759,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, int seg, bus, slot, func, align_order, count; resource_size_t align = 0; char *p; + bool invalid = false; spin_lock(&resource_alignment_lock); p = resource_alignment_param; @@ -4777,16 +4778,49 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, } else { align_order = -1; } - if (sscanf(p, "%x:%x:%x.%x%n", - &seg, &bus, &slot, &func, &count) != 4) { + if (p[0] == '*' && p[1] == ':') { + seg = -1; + count = 1; + } else if (sscanf(p, "%x%n", &seg, &count) != 1 || + p[count] != ':') { + invalid = true; + break; + } + p += count + 1; + if (*p == '*') { + bus = -1; + count = 1; + } else if (sscanf(p, "%x%n", &bus, &count) != 1) { + invalid = true; + break; + } + p += count; + if (*p == '.') { + slot = bus; + bus = seg; seg = 0; - if (sscanf(p, "%x:%x.%x%n", - &bus, &slot, &func, &count) != 3) { - /* Invalid format */ - printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n", - p); + p++; + } else if (*p == ':') { + p++; + if (p[0] == '*' && p[1] == '.') { + slot = -1; + count = 1; + } else if (sscanf(p, "%x%n", &slot, &count) != 1 || + p[count] != '.') { + invalid = true; break; } + p += count + 1; + } else { + invalid = true; + break; + } + if (*p == '*') { + func = -1; + count = 1; + } else if (sscanf(p, "%x%n", &func, &count) != 1) { + invalid = true; + break; } p += count; if (!strncmp(p, ":noresize", 9)) { @@ -4794,10 +4828,10 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, p += 9; } else *resize = true; - if (seg == pci_domain_nr(dev->bus) && - bus == dev->bus->number && - slot == PCI_SLOT(dev->devfn) && - func == PCI_FUNC(dev->devfn)) { + if ((seg == pci_domain_nr(dev->bus) || seg == -1) && + (bus == dev->bus->number || bus == -1) && + (slot == PCI_SLOT(dev->devfn) || slot == -1) && + (func == PCI_FUNC(dev->devfn) || func == -1)) { if (align_order == -1) align = PAGE_SIZE; else @@ -4807,10 +4841,14 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, } if (*p != ';' && *p != ',') { /* End of param or invalid format */ + invalid = true; break; } p++; } + if (invalid) + printk(KERN_ERR "PCI: Can't parse resource_alignment parameter:%s\n", + p); spin_unlock(&resource_alignment_lock); return align; } -- 1.7.9.5