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Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kb56c-0002Pa-7h; Fri, 06 Nov 2020 10:00:56 -0700 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.92) (envelope-from ) id 1kb56W-0004tW-1a; Fri, 06 Nov 2020 10:00:48 -0700 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org Cc: Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?UTF-8?q?Christian=20K=C3=B6nig?= , Ira Weiny , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Logan Gunthorpe Date: Fri, 6 Nov 2020 10:00:36 -0700 Message-Id: <20201106170036.18713-16-logang@deltatee.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201106170036.18713-1-logang@deltatee.com> References: <20201106170036.18713-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, sbates@raithlin.com, hch@lst.de, jgg@ziepe.ca, christian.koenig@amd.com, dan.j.williams@intel.com, iweiny@intel.com, jhubbard@nvidia.com, ddutile@redhat.com, willy@infradead.org, daniel.vetter@ffwll.ch, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [RFC PATCH 15/15] nvme-pci: Allow mmaping the CMB in userspace X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Content-Transfer-Encoding: quoted-printable 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 | 11 +++++++++++ drivers/nvme/host/nvme.h | 1 + drivers/nvme/host/pci.c | 9 +++++++++ 3 files changed, 21 insertions(+) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index f14316c9b34a..fc642aba671d 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3240,12 +3240,23 @@ static long nvme_dev_ioctl(struct file *file, uns= igned int cmd, } } =20 +static int nvme_dev_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct nvme_ctrl *ctrl =3D 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 =3D { .owner =3D THIS_MODULE, .open =3D nvme_dev_open, .release =3D nvme_dev_release, .unlocked_ioctl =3D nvme_dev_ioctl, .compat_ioctl =3D compat_ptr_ioctl, + .mmap =3D nvme_dev_mmap, }; =20 static ssize_t nvme_sysfs_reset(struct device *dev, diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index a0bfe8709cfc..3d790d849701 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -473,6 +473,7 @@ 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); + int (*mmap_cmb)(struct nvme_ctrl *ctrl, struct vm_area_struct *vma); }; =20 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 26976bdf4af0..9c61573111ea 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -2687,6 +2687,14 @@ static bool nvme_pci_supports_pci_p2pdma(struct nv= me_ctrl *ctrl) return dma_pci_p2pdma_supported(dev->dev); } =20 +static int nvme_pci_mmap_cmb(struct nvme_ctrl *ctrl, + struct vm_area_struct *vma) +{ + struct pci_dev *pdev =3D to_pci_dev(to_nvme_dev(ctrl)->dev); + + return pci_mmap_p2pmem(pdev, vma); +} + static const struct nvme_ctrl_ops nvme_pci_ctrl_ops =3D { .name =3D "pcie", .module =3D THIS_MODULE, @@ -2698,6 +2706,7 @@ static const struct nvme_ctrl_ops nvme_pci_ctrl_ops= =3D { .submit_async_event =3D nvme_pci_submit_async_event, .get_address =3D nvme_pci_get_address, .supports_pci_p2pdma =3D nvme_pci_supports_pci_p2pdma, + .mmap_cmb =3D nvme_pci_mmap_cmb, }; =20 static int nvme_dev_map(struct nvme_dev *dev) --=20 2.20.1