From patchwork Thu Sep 16 23:41:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 12500597 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 90263C4321E for ; Thu, 16 Sep 2021 23:41:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4BE8F610C7 for ; Thu, 16 Sep 2021 23:41:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4BE8F610C7 Authentication-Results: mail.kernel.org; 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dkim=pass header.d=deltatee.com header.s=20200525 header.b="hN6uw/Ed"; dmarc=pass (policy=none) header.from=deltatee.com; spf=pass (imf28.hostedemail.com: domain of gunthorp@deltatee.com designates 204.191.154.188 as permitted sender) smtp.mailfrom=gunthorp@deltatee.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 726A590000BC X-HE-Tag: 1631835687-662298 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Allow userspace to obtain CMB memory by mmaping the controller's char device. The mmap call allocates and returns a hunk of CMB memory, (the offset is ignored) so userspace does not have control over the address within the CMB. A VMA allocated in this way will only be usable by drivers that set FOLL_PCI_P2PDMA when calling GUP. And inter-device support will be checked the first time the pages are mapped for DMA. Currently this is only supported by O_DIRECT to an PCI NVMe device or through the NVMe passthrough IOCTL. Signed-off-by: Logan Gunthorpe --- drivers/nvme/host/core.c | 15 +++++++++++++++ drivers/nvme/host/nvme.h | 2 ++ drivers/nvme/host/pci.c | 18 ++++++++++++++++++ 3 files changed, 35 insertions(+) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 916750a54f60..dfc18f0bdeee 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3075,6 +3075,10 @@ static int nvme_dev_open(struct inode *inode, struct file *file) } file->private_data = ctrl; + + if (ctrl->ops->mmap_file_open) + ctrl->ops->mmap_file_open(ctrl, file); + return 0; } @@ -3088,12 +3092,23 @@ static int nvme_dev_release(struct inode *inode, struct file *file) return 0; } +static int nvme_dev_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct nvme_ctrl *ctrl = file->private_data; + + if (!ctrl->ops->mmap_cmb) + return -ENODEV; + + return ctrl->ops->mmap_cmb(ctrl, vma); +} + static const struct file_operations nvme_dev_fops = { .owner = THIS_MODULE, .open = nvme_dev_open, .release = nvme_dev_release, .unlocked_ioctl = nvme_dev_ioctl, .compat_ioctl = compat_ptr_ioctl, + .mmap = nvme_dev_mmap, }; static ssize_t nvme_sysfs_reset(struct device *dev, diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index fb9bfc52a6d7..1cc721290d4c 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -485,6 +485,8 @@ struct nvme_ctrl_ops { void (*delete_ctrl)(struct nvme_ctrl *ctrl); int (*get_address)(struct nvme_ctrl *ctrl, char *buf, int size); bool (*supports_pci_p2pdma)(struct nvme_ctrl *ctrl); + void (*mmap_file_open)(struct nvme_ctrl *ctrl, struct file *file); + int (*mmap_cmb)(struct nvme_ctrl *ctrl, struct vm_area_struct *vma); }; /* diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index e2cd73129a88..9d69e4a3d62e 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -2870,6 +2870,22 @@ static bool nvme_pci_supports_pci_p2pdma(struct nvme_ctrl *ctrl) return dma_pci_p2pdma_supported(dev->dev); } +static void nvme_pci_mmap_file_open(struct nvme_ctrl *ctrl, + struct file *file) +{ + struct pci_dev *pdev = to_pci_dev(to_nvme_dev(ctrl)->dev); + + pci_p2pdma_mmap_file_open(pdev, file); +} + +static int nvme_pci_mmap_cmb(struct nvme_ctrl *ctrl, + struct vm_area_struct *vma) +{ + struct pci_dev *pdev = to_pci_dev(to_nvme_dev(ctrl)->dev); + + return pci_mmap_p2pmem(pdev, vma); +} + static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = { .name = "pcie", .module = THIS_MODULE, @@ -2881,6 +2897,8 @@ static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = { .submit_async_event = nvme_pci_submit_async_event, .get_address = nvme_pci_get_address, .supports_pci_p2pdma = nvme_pci_supports_pci_p2pdma, + .mmap_file_open = nvme_pci_mmap_file_open, + .mmap_cmb = nvme_pci_mmap_cmb, }; static int nvme_dev_map(struct nvme_dev *dev)