From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932129AbdCTXIP (ORCPT ); Mon, 20 Mar 2017 19:08:15 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55125 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932096AbdCTXIO (ORCPT ); Mon, 20 Mar 2017 19:08:14 -0400 Date: Tue, 21 Mar 2017 10:07:06 +1100 From: Gavin Shan To: bodong@mellanox.com Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, saeedm@mellanox.com, Eli Cohen Subject: Re: [PATCH] pci/sriov: Add an option to probe VFs or not before enabling SR-IOV Reply-To: Gavin Shan References: <1490022874-54718-1-git-send-email-bodong@mellanox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490022874-54718-1-git-send-email-bodong@mellanox.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-MML: disable x-cbid: 17032023-0052-0000-0000-000002268716 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17032023-0053-0000-0000-000007FEC888 Message-Id: <20170320230706.GA12252@gwshan> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-03-20_16:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=3 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703200195 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 20, 2017 at 05:14:34PM +0200, bodong@mellanox.com wrote: >From: Bodong Wang > >Sometimes it is not desirable to probe the virtual functions after >SRIOV is enabled. This can save host side resource usage by VF >instances which would be eventually probed to VMs. > >Added a new PCI sysfs interface "sriov_probe_vfs" to control that >from PF, all current callers still retain the same functionality. >To modify it, echo 0/n/N (disable probe) or 1/y/Y (enable probe) to > >/sys/bus/pci/devices//sriov_probe_vfs > >Note that, the choice must be made before enabling VFs. The change >will not take effect if VFs are already enabled. Simply, one can set >sriov_numvfs to 0, choose whether to probe or not, and then resume >sriov_numvfs. > Bodong, I'm not sure if there is a requirement to load driver for the specified number of VFs? That indicates no driver will be loaded for other VFs. If so, this interface might serve the purpose as well. >Change-Id: I48e6db1e8c7b364bb371590e2b13b4d7ee87713c >Signed-off-by: Bodong Wang >Signed-off-by: Eli Cohen >--- > Documentation/PCI/pci-iov-howto.txt | 10 ++++++++++ > drivers/pci/iov.c | 1 + > drivers/pci/pci-driver.c | 15 +++++++++++---- > drivers/pci/pci-sysfs.c | 28 ++++++++++++++++++++++++++++ > drivers/pci/pci.h | 1 + > 5 files changed, 51 insertions(+), 4 deletions(-) > >diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.txt >index 2d91ae2..902a528 100644 >--- a/Documentation/PCI/pci-iov-howto.txt >+++ b/Documentation/PCI/pci-iov-howto.txt >@@ -68,6 +68,16 @@ To disable SR-IOV capability: > echo 0 > \ > /sys/bus/pci/devices//sriov_numvfs > >+To enable probing VFs by a compatible driver on the host: >+Before enabling SR-IOV capabilities, do: >+ echo 1 > \ >+ /sys/bus/pci/devices//sriov_probe_vfs >+ >+To disable probing VFs by a compatible driver on the host: >+Before enabling SR-IOV capabilities, do: >+ echo 0 > \ >+ /sys/bus/pci/devices//sriov_probe_vfs >+ > 3.2 Usage example > > Following piece of code illustrates the usage of the SR-IOV API. >diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c >index 2479ae8..70691de 100644 >--- a/drivers/pci/iov.c >+++ b/drivers/pci/iov.c >@@ -450,6 +450,7 @@ static int sriov_init(struct pci_dev *dev, int pos) > iov->total_VFs = total; > iov->pgsz = pgsz; > iov->self = dev; >+ iov->probe_vfs = true; > pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap); > pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link); > if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) >diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c >index afa7271..930552c 100644 >--- a/drivers/pci/pci-driver.c >+++ b/drivers/pci/pci-driver.c >@@ -405,11 +405,18 @@ static int pci_device_probe(struct device *dev) > return error; > > pci_dev_get(pci_dev); >- error = __pci_device_probe(drv, pci_dev); >- if (error) { >- pcibios_free_irq(pci_dev); >- pci_dev_put(pci_dev); >+#ifdef CONFIG_PCI_IOV >+ if (!pci_dev->is_virtfn || >+ (pci_dev->is_virtfn && pci_dev->physfn->sriov->probe_vfs)) { >+#endif >+ error = __pci_device_probe(drv, pci_dev); >+ if (error) { >+ pcibios_free_irq(pci_dev); >+ pci_dev_put(pci_dev); >+ } >+#ifdef CONFIG_PCI_IOV > } >+#endif > I think it's reasonable to have a inline function for this check: #ifdef CONFIG_PCI_IOV static inline bool pci_device_can_probe(struct pci_dev *pdev) { return (!pdev->is_virtfn || pdev->physfn->sriov->probe_vfs); } #else static inline bool pci_device_can_probe(struct pci_dev *pdev) { return true; } #endif > return error; > } >diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c >index 25d010d..1d5b89d 100644 >--- a/drivers/pci/pci-sysfs.c >+++ b/drivers/pci/pci-sysfs.c >@@ -526,10 +526,37 @@ static ssize_t sriov_numvfs_store(struct device *dev, > return count; > } > >+static ssize_t sriov_probe_vfs_show(struct device *dev, >+ struct device_attribute *attr, >+ char *buf) >+{ >+ struct pci_dev *pdev = to_pci_dev(dev); >+ >+ return sprintf(buf, "%u\n", pdev->sriov->probe_vfs); >+} >+ >+static ssize_t sriov_probe_vfs_store(struct device *dev, >+ struct device_attribute *attr, >+ const char *buf, size_t count) >+{ >+ struct pci_dev *pdev = to_pci_dev(dev); >+ bool probe_vfs; >+ >+ if (kstrtobool(buf, &probe_vfs) < 0) >+ return -EINVAL; >+ >+ pdev->sriov->probe_vfs = probe_vfs; >+ >+ return count; >+} >+ > static struct device_attribute sriov_totalvfs_attr = __ATTR_RO(sriov_totalvfs); > static struct device_attribute sriov_numvfs_attr = > __ATTR(sriov_numvfs, (S_IRUGO|S_IWUSR|S_IWGRP), > sriov_numvfs_show, sriov_numvfs_store); >+static struct device_attribute sriov_probe_vfs_attr = >+ __ATTR(sriov_probe_vfs, (S_IRUGO|S_IWUSR|S_IWGRP), >+ sriov_probe_vfs_show, sriov_probe_vfs_store); > #endif /* CONFIG_PCI_IOV */ > > static ssize_t driver_override_store(struct device *dev, >@@ -1549,6 +1576,7 @@ static umode_t pci_dev_hp_attrs_are_visible(struct kobject *kobj, > static struct attribute *sriov_dev_attrs[] = { > &sriov_totalvfs_attr.attr, > &sriov_numvfs_attr.attr, >+ &sriov_probe_vfs_attr.attr, > NULL, > }; > >diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h >index 8dd38e6..a62c6bf 100644 >--- a/drivers/pci/pci.h >+++ b/drivers/pci/pci.h >@@ -272,6 +272,7 @@ struct pci_sriov { > struct pci_dev *self; /* this PF */ > struct mutex lock; /* lock for setting sriov_numvfs in sysfs */ > resource_size_t barsz[PCI_SRIOV_NUM_BARS]; /* VF BAR size */ >+ bool probe_vfs; /* probe VFs or not */ > }; > > #ifdef CONFIG_PCI_ATS Thanks, Gavin