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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 017B6C433E0 for ; Tue, 12 Jan 2021 03:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95DCF22D6D for ; Tue, 12 Jan 2021 03:27:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726899AbhALD1U (ORCPT ); Mon, 11 Jan 2021 22:27:20 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:27595 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726893AbhALD1U (ORCPT ); Mon, 11 Jan 2021 22:27:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610421952; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VWr2T052hL7ZZCsKGI4QVVcBlDC0MV1Qygnm5Lbm6KM=; b=MQskBarsZxw/0up/8jyLrbkPbV7U/8esldN1OtGy15WYWpEJgVWgV324P+8y5o/3E2Yv7J zaxg17I6YQOCX8bgwv166Si0yfBrcUFCAHxK1FX+aQfTwU767R+gYVRLgcPGM4TDSKHgvE +GiOkdb7Ii2NGIBO2a+5NaZ5LwvtE8U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-526-Xtqb7fN6MuKZ4t61dfMkKg-1; Mon, 11 Jan 2021 22:25:48 -0500 X-MC-Unique: Xtqb7fN6MuKZ4t61dfMkKg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 994D8804002; Tue, 12 Jan 2021 03:25:46 +0000 (UTC) Received: from [10.3.112.139] (ovpn-112-139.phx2.redhat.com [10.3.112.139]) by smtp.corp.redhat.com (Postfix) with ESMTP id 96EC85B4A7; Tue, 12 Jan 2021 03:25:42 +0000 (UTC) Subject: Re: [PATCH mlx5-next v1 1/5] PCI: Add sysfs callback to allow MSI-X table size change of SR-IOV VFs To: Alexander Duyck , Leon Romanovsky Cc: Bjorn Helgaas , Saeed Mahameed , Leon Romanovsky , Jason Gunthorpe , Jakub Kicinski , linux-pci , linux-rdma@vger.kernel.org, Netdev , Alex Williamson References: <20210110150727.1965295-1-leon@kernel.org> <20210110150727.1965295-2-leon@kernel.org> From: Don Dutile Message-ID: <397a7ed5-c98f-560e-107e-0b354bebb9bd@redhat.com> Date: Mon, 11 Jan 2021 22:25:42 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 1/11/21 2:30 PM, Alexander Duyck wrote: > On Sun, Jan 10, 2021 at 7:12 AM 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/.../vf_msix_vec 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 | 62 +++++++++++++++++++++++++ >> drivers/pci/msi.c | 29 ++++++++++++ >> drivers/pci/pci-sysfs.c | 1 + >> drivers/pci/pci.h | 2 + >> include/linux/pci.h | 8 +++- >> 6 files changed, 121 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci >> index 25c9c39770c6..05e26e5da54e 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/.../vf_msix_vec > So the name for this doesn't seem to match existing SR-IOV naming. It > seems like this should probably be something like sriov_vf_msix_count > in order to be closer to the actual naming of what is being dealt > with. > >> +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 >> + supports the ->sriov_set_msix_vec_count() callback and there >> + is no driver bound to the VF. >> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c >> index 4afd4ee4f7f0..42c0df4158d1 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 +427,67 @@ const struct attribute_group sriov_dev_attr_group = { >> .is_visible = sriov_attrs_are_visible, >> }; >> >> +#ifdef CONFIG_PCI_MSI >> +static ssize_t vf_msix_vec_show(struct device *dev, >> + struct device_attribute *attr, char *buf) >> +{ >> + struct pci_dev *pdev = to_pci_dev(dev); >> + int numb = pci_msix_vec_count(pdev); >> + struct pci_dev *pfdev; >> + >> + if (numb < 0) >> + return numb; >> + >> + pfdev = pci_physfn(pdev); >> + if (!pfdev->driver || !pfdev->driver->sriov_set_msix_vec_count) >> + return -EOPNOTSUPP; >> + > This doesn't make sense to me. You are getting the vector count for > the PCI device and reporting that. Are you expecting to call this on > the PF or the VFs? It seems like this should be a PF attribute and not > be called on the individual VFs. > > If you are calling this on the VFs then it doesn't really make any > sense anyway since the VF is not a "VF PCI dev representor" and > shouldn't be treated as such. In my opinion if we are going to be > doing per-port resource limiting that is something that might make > more sense as a part of the devlink configuration for the VF since the > actual change won't be visible to an assigned device. if the op were just limited to nic ports, devlink may be used; but I believe Leon is trying to handle it from an sriov/vf perspective for other non-nic devices as well, e.g., ib ports, nvme vf's (which don't have a port concept at all). >> + return sprintf(buf, "%d\n", numb); >> +} >> + >> +static ssize_t vf_msix_vec_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(vf_msix_vec); >> +#endif >> + >> +static struct attribute *sriov_vf_dev_attrs[] = { >> +#ifdef CONFIG_PCI_MSI >> + &dev_attr_vf_msix_vec.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; >> + >> + 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..20705ca94666 100644 >> --- a/drivers/pci/msi.c >> +++ b/drivers/pci/msi.c >> @@ -991,6 +991,35 @@ 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. >> + * @dev: VF device that is going to be changed >> + * @numb: amount of MSI-X vectors >> + **/ >> +int pci_set_msix_vec_count(struct pci_dev *dev, int numb) >> +{ >> + struct pci_dev *pdev = pci_physfn(dev); >> + >> + if (!dev->msix_cap || !pdev->msix_cap) >> + return -EINVAL; >> + >> + if (dev->driver || !pdev->driver || >> + !pdev->driver->sriov_set_msix_vec_count) >> + return -EOPNOTSUPP; >> + >> + if (numb < 0) >> + /* >> + * We don't support negative numbers for now, >> + * but maybe in the future it will make sense. >> + */ >> + return -EINVAL; >> + >> + return pdev->driver->sriov_set_msix_vec_count(dev, numb); >> +} >> + > If you are going to have a set operation for this it would make sense > to have a get operation. Your show operation seems unbalanced since > you are expecting to call it on the VF directly which just seems > wrong. > >> 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..1fd273077637 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 numb); >> #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..a17cfc28eb66 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. > Hopefully it is doing more than just changing the displayed sysfs > value. What is the effect of changing that value on the actual system > state? I'm assuming this is some limit that is enforced by the PF or > the device firmware? > > >> * @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; >> @@ -2057,7 +2060,6 @@ void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar); >> >> #ifdef CONFIG_PCI_IOV >> int pci_iov_virtfn_bus(struct pci_dev *dev, int id); >> -int pci_iov_virtfn_devfn(struct pci_dev *dev, int id); >> >> int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); >> void pci_disable_sriov(struct pci_dev *dev); >> @@ -2402,6 +2404,10 @@ static inline bool pci_is_thunderbolt_attached(struct pci_dev *pdev) >> void pci_uevent_ers(struct pci_dev *pdev, enum pci_ers_result err_type); >> #endif >> >> +#ifdef CONFIG_PCI_IOV >> +int pci_iov_virtfn_devfn(struct pci_dev *dev, int vf_id); >> +#endif >> + >> /* Provide the legacy pci_dma_* API */ >> #include >> >> -- >> 2.29.2 >>