From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9EAA0C433E6 for ; Sat, 16 Jan 2021 08:24:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53C0220DD4 for ; Sat, 16 Jan 2021 08:24:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726138AbhAPIYR (ORCPT ); Sat, 16 Jan 2021 03:24:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:47076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbhAPIYQ (ORCPT ); Sat, 16 Jan 2021 03:24:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 522C5221E2; Sat, 16 Jan 2021 08:23:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610785415; bh=K1zcB4rMjn2+8P4ZdMDNTk6C3ITEG5H+9xeG2Sn37j8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uTDScZ6VGD2MZw8euIh7g2m8qgB+yNEnmddV4nih1gEMevO0bnnE45FuRbHWN8olN in27Xfo750/qCgZjXoe2Xa2RIoDheVD4M71ZncZTkSXxCrgK4Z9zqHltALqZbKA86K LMH8NSCtg40PMrCn+YEJbj39aEY/xiIjChsC31wjbZwwc+6NogtjoXKdU+MxihaiAy KCmhSUoMWg7hfNwR8ZuazfJX/9mzmPJs79jzdJW3A5v2Mfsz4+mL36JGq96lkdpCyi /MnFTjhyKiuh6jbhyfHBvb7Advd+yfH0nzzuzzi1CkFxm2XRAKwYnOWrPsGT4AfXjN 5CAeTPV2RYW3w== Date: Sat, 16 Jan 2021 10:23:31 +0200 From: Leon Romanovsky To: Alex Williamson Cc: Bjorn Helgaas , Saeed Mahameed , Jason Gunthorpe , Jakub Kicinski , linux-pci@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, Don Dutile , Alexander Duyck Subject: Re: [PATCH mlx5-next v2 1/5] PCI: Add sysfs callback to allow MSI-X table size change of SR-IOV VFs Message-ID: <20210116082331.GL944463@unreal> References: <20210114103140.866141-1-leon@kernel.org> <20210114103140.866141-2-leon@kernel.org> <20210114170543.143cce49@omen.home.shazbot.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210114170543.143cce49@omen.home.shazbot.org> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jan 14, 2021 at 05:05:43PM -0700, Alex Williamson wrote: > On Thu, 14 Jan 2021 12:31:36 +0200 > Leon Romanovsky wrote: > > > From: Leon Romanovsky > > > > Extend PCI sysfs interface with a new callback that allows configure > > the number of MSI-X vectors for specific SR-IO VF. This is needed > > to optimize the performance of newly bound devices by allocating > > the number of vectors based on the administrator knowledge of targeted VM. > > > > This function is applicable for SR-IOV VF because such devices allocate > > their MSI-X table before they will run on the VMs and HW can't guess the > > right number of vectors, so the HW allocates them statically and equally. > > > > The newly added /sys/bus/pci/devices/.../sriov_vf_msix_count file will be seen > > for the VFs and it is writable as long as a driver is not bounded to the VF. > > > > The values accepted are: > > * > 0 - this will be number reported by the VF's MSI-X capability > > * < 0 - not valid > > * = 0 - will reset to the device default value > > > > Signed-off-by: Leon Romanovsky > > --- > > Documentation/ABI/testing/sysfs-bus-pci | 20 +++++++++ > > drivers/pci/iov.c | 58 +++++++++++++++++++++++++ > > drivers/pci/msi.c | 47 ++++++++++++++++++++ > > drivers/pci/pci-sysfs.c | 1 + > > drivers/pci/pci.h | 2 + > > include/linux/pci.h | 3 ++ > > 6 files changed, 131 insertions(+) > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci > > index 25c9c39770c6..34a8c6bcde70 100644 > > --- a/Documentation/ABI/testing/sysfs-bus-pci > > +++ b/Documentation/ABI/testing/sysfs-bus-pci > > @@ -375,3 +375,23 @@ Description: > > The value comes from the PCI kernel device state and can be one > > of: "unknown", "error", "D0", D1", "D2", "D3hot", "D3cold". > > The file is read only. > > + > > +What: /sys/bus/pci/devices/.../sriov_vf_msix_count > > +Date: December 2020 > > +Contact: Leon Romanovsky > > +Description: > > + This file is associated with the SR-IOV VFs. > > + It allows configuration of the number of MSI-X vectors for > > + the VF. This is needed to optimize performance of newly bound > > + devices by allocating the number of vectors based on the > > + administrator knowledge of targeted VM. > > + > > + The values accepted are: > > + * > 0 - this will be number reported by the VF's MSI-X > > + capability > > + * < 0 - not valid > > + * = 0 - will reset to the device default value > > + > > + The file is writable if the PF is bound to a driver that > > + set sriov_vf_total_msix > 0 and there is no driver bound > > + to the VF. > > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c > > index 4afd4ee4f7f0..5bc496f8ffa3 100644 > > --- a/drivers/pci/iov.c > > +++ b/drivers/pci/iov.c > > @@ -31,6 +31,7 @@ int pci_iov_virtfn_devfn(struct pci_dev *dev, int vf_id) > > return (dev->devfn + dev->sriov->offset + > > dev->sriov->stride * vf_id) & 0xff; > > } > > +EXPORT_SYMBOL(pci_iov_virtfn_devfn); > > > > /* > > * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may > > @@ -426,6 +427,63 @@ const struct attribute_group sriov_dev_attr_group = { > > .is_visible = sriov_attrs_are_visible, > > }; > > > > +#ifdef CONFIG_PCI_MSI > > +static ssize_t sriov_vf_msix_count_show(struct device *dev, > > + struct device_attribute *attr, > > + char *buf) > > +{ > > + struct pci_dev *pdev = to_pci_dev(dev); > > + int count = pci_msix_vec_count(pdev); > > + > > + if (count < 0) > > + return count; > > + > > + return sprintf(buf, "%d\n", count); > > +} > > + > > +static ssize_t sriov_vf_msix_count_store(struct device *dev, > > + struct device_attribute *attr, > > + const char *buf, size_t count) > > +{ > > + struct pci_dev *vf_dev = to_pci_dev(dev); > > + int val, ret; > > + > > + ret = kstrtoint(buf, 0, &val); > > + if (ret) > > + return ret; > > + > > + ret = pci_set_msix_vec_count(vf_dev, val); > > + if (ret) > > + return ret; > > + > > + return count; > > +} > > +static DEVICE_ATTR_RW(sriov_vf_msix_count); > > +#endif > > + > > +static struct attribute *sriov_vf_dev_attrs[] = { > > +#ifdef CONFIG_PCI_MSI > > + &dev_attr_sriov_vf_msix_count.attr, > > +#endif > > + NULL, > > +}; > > + > > +static umode_t sriov_vf_attrs_are_visible(struct kobject *kobj, > > + struct attribute *a, int n) > > +{ > > + struct device *dev = kobj_to_dev(kobj); > > + > > + if (dev_is_pf(dev)) > > + return 0; > > Wouldn't it be cleaner to also hide this on VFs where > pci_msix_vec_count() returns an error or where the PF driver doesn't > implement .sriov_set_msix_vec_count()? IOW, expose it only where it > could actually work. I wasn't sure about the policy in PCI/core, but sure will change. > > > + > > + return a->mode; > > +} > > + > > +const struct attribute_group sriov_vf_dev_attr_group = { > > + .attrs = sriov_vf_dev_attrs, > > + .is_visible = sriov_vf_attrs_are_visible, > > +}; > > + > > int __weak pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs) > > { > > return 0; > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > > index 3162f88fe940..5a40200343c9 100644 > > --- a/drivers/pci/msi.c > > +++ b/drivers/pci/msi.c > > @@ -991,6 +991,53 @@ int pci_msix_vec_count(struct pci_dev *dev) > > } > > EXPORT_SYMBOL(pci_msix_vec_count); > > > > +/** > > + * pci_set_msix_vec_count - change the reported number of MSI-X vectors > > + * This function is applicable for SR-IOV VF because such devices allocate > > + * their MSI-X table before they will run on the VMs and HW can't guess the > > + * right number of vectors, so the HW allocates them statically and equally. > > Nit, this is an assumption of the VF usage and conjecture of the > implementation. This is one of the possible implementations. > > > + * @dev: VF device that is going to be changed > > + * @count amount of MSI-X vectors > > + **/ > > +int pci_set_msix_vec_count(struct pci_dev *dev, int count) > > pci_vf_set_msix_vec_count()? Long, I know, but if it's limited to VFs > name it accordingly. Thanks, I'll do. > > Alex > > > +{ > > + struct pci_dev *pdev = pci_physfn(dev); > > + int ret; > > + > > + if (!dev->msix_cap || !pdev->msix_cap || count < 0) > > + /* > > + * We don't support negative numbers for now, > > + * but maybe in the future it will make sense. > > + */ > > + return -EINVAL; > > + > > + device_lock(&pdev->dev); > > + if (!pdev->driver || !pdev->driver->sriov_set_msix_vec_count) { > > + ret = -EOPNOTSUPP; > > + goto err_pdev; > > + } > > + > > + device_lock(&dev->dev); > > + if (dev->driver) { > > + /* > > + * Driver already probed this VF and configured itself > > + * based on previously configured (or default) MSI-X vector > > + * count. It is too late to change this field for this > > + * specific VF. > > + */ > > + ret = -EBUSY; > > + goto err_dev; > > + } > > + > > + ret = pdev->driver->sriov_set_msix_vec_count(dev, count); > > + > > +err_dev: > > + device_unlock(&dev->dev); > > +err_pdev: > > + device_unlock(&pdev->dev); > > + return ret; > > +} > > + > > static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, > > int nvec, struct irq_affinity *affd, int flags) > > { > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > index fb072f4b3176..0af2222643c2 100644 > > --- a/drivers/pci/pci-sysfs.c > > +++ b/drivers/pci/pci-sysfs.c > > @@ -1557,6 +1557,7 @@ static const struct attribute_group *pci_dev_attr_groups[] = { > > &pci_dev_hp_attr_group, > > #ifdef CONFIG_PCI_IOV > > &sriov_dev_attr_group, > > + &sriov_vf_dev_attr_group, > > #endif > > &pci_bridge_attr_group, > > &pcie_dev_attr_group, > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > > index 5c59365092fa..dbbfa9e73ea8 100644 > > --- a/drivers/pci/pci.h > > +++ b/drivers/pci/pci.h > > @@ -183,6 +183,7 @@ extern unsigned int pci_pm_d3hot_delay; > > > > #ifdef CONFIG_PCI_MSI > > void pci_no_msi(void); > > +int pci_set_msix_vec_count(struct pci_dev *dev, int count); > > #else > > static inline void pci_no_msi(void) { } > > #endif > > @@ -502,6 +503,7 @@ resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno); > > void pci_restore_iov_state(struct pci_dev *dev); > > int pci_iov_bus_range(struct pci_bus *bus); > > extern const struct attribute_group sriov_dev_attr_group; > > +extern const struct attribute_group sriov_vf_dev_attr_group; > > #else > > static inline int pci_iov_init(struct pci_dev *dev) > > { > > diff --git a/include/linux/pci.h b/include/linux/pci.h > > index b32126d26997..6be96d468eda 100644 > > --- a/include/linux/pci.h > > +++ b/include/linux/pci.h > > @@ -856,6 +856,8 @@ struct module; > > * e.g. drivers/net/e100.c. > > * @sriov_configure: Optional driver callback to allow configuration of > > * number of VFs to enable via sysfs "sriov_numvfs" file. > > + * @sriov_set_msix_vec_count: Driver callback to change number of MSI-X vectors > > + * exposed by the sysfs "vf_msix_vec" entry. > > * @err_handler: See Documentation/PCI/pci-error-recovery.rst > > * @groups: Sysfs attribute groups. > > * @driver: Driver model structure. > > @@ -871,6 +873,7 @@ struct pci_driver { > > int (*resume)(struct pci_dev *dev); /* Device woken up */ > > void (*shutdown)(struct pci_dev *dev); > > int (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */ > > + int (*sriov_set_msix_vec_count)(struct pci_dev *vf, int msix_vec_count); /* On PF */ > > const struct pci_error_handlers *err_handler; > > const struct attribute_group **groups; > > struct device_driver driver; > > -- > > 2.29.2 > > >