Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753273AbdCTPW1 (ORCPT ); Mon, 20 Mar 2017 11:22:27 -0400 Received: from mail-il-dmz.mellanox.com ([193.47.165.129]:53620 "EHLO mellanox.co.il" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753081AbdCTPVv (ORCPT ); Mon, 20 Mar 2017 11:21:51 -0400 From: bodong@mellanox.com To: bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, saeedm@mellanox.com, Bodong Wang , Eli Cohen Subject: [PATCH] pci/sriov: Add an option to probe VFs or not before enabling SR-IOV Date: Mon, 20 Mar 2017 17:14:34 +0200 Message-Id: <1490022874-54718-1-git-send-email-bodong@mellanox.com> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5092 Lines: 152 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. 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 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 -- 1.8.3.1