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[85.223.209.54]) by smtp.gmail.com with ESMTPSA id l7-v6sm314231ljh.53.2018.05.25.08.33.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 25 May 2018 08:33:49 -0700 (PDT) From: Oleksandr Andrushchenko To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, jgross@suse.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Cc: daniel.vetter@intel.com, andr2000@gmail.com, dongwon.kim@intel.com, matthew.d.roper@intel.com, Oleksandr Andrushchenko Subject: [PATCH 5/8] xen/gntdev: Add initial support for dma-buf UAPI Date: Fri, 25 May 2018 18:33:28 +0300 Message-Id: <20180525153331.31188-6-andr2000@gmail.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180525153331.31188-1-andr2000@gmail.com> References: <20180525153331.31188-1-andr2000@gmail.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Oleksandr Andrushchenko Add UAPI and IOCTLs for dma-buf grant device driver extension: the extension allows userspace processes and kernel modules to use Xen backed dma-buf implementation. With this extension grant references to the pages of an imported dma-buf can be exported for other domain use and grant references coming from a foreign domain can be converted into a local dma-buf for local export. Implement basic initialization and stubs for Xen DMA buffers' support. Signed-off-by: Oleksandr Andrushchenko --- drivers/xen/Kconfig | 10 +++ drivers/xen/gntdev.c | 148 ++++++++++++++++++++++++++++++++++++++ include/uapi/xen/gntdev.h | 91 +++++++++++++++++++++++ 3 files changed, 249 insertions(+) diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index 3431fe210624..eaf63a2c7ae6 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -152,6 +152,16 @@ config XEN_GNTDEV help Allows userspace processes to use grants. +config XEN_GNTDEV_DMABUF + bool "Add support for dma-buf grant access device driver extension" + depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC + help + Allows userspace processes and kernel modules to use Xen backed + dma-buf implementation. With this extension grant references to + the pages of an imported dma-buf can be exported for other domain + use and grant references coming from a foreign domain can be + converted into a local dma-buf for local export. + config XEN_GRANT_DEV_ALLOC tristate "User-space grant reference allocator driver" depends on XEN diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 640a579f42ea..9e450622af1a 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -6,6 +6,7 @@ * * Copyright (c) 2006-2007, D G Murray. * (c) 2009 Gerd Hoffmann + * (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of @@ -122,6 +123,17 @@ struct grant_map { #endif }; +#ifdef CONFIG_XEN_GNTDEV_DMABUF +struct xen_dmabuf { + union { + struct { + /* Granted references of the imported buffer. */ + grant_ref_t *refs; + } imp; + } u; +}; +#endif + static int unmap_grant_pages(struct grant_map *map, int offset, int pages); static struct miscdevice gntdev_miscdev; @@ -1036,6 +1048,128 @@ static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) return ret; } +#ifdef CONFIG_XEN_GNTDEV_DMABUF +/* ------------------------------------------------------------------ */ +/* DMA buffer export support. */ +/* ------------------------------------------------------------------ */ + +static int dmabuf_exp_wait_released(struct gntdev_priv *priv, int fd, + int wait_to_ms) +{ + return -ETIMEDOUT; +} + +static int dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags, + int count, u32 domid, u32 *refs, u32 *fd) +{ + *fd = -1; + return -EINVAL; +} + +/* ------------------------------------------------------------------ */ +/* DMA buffer import support. */ +/* ------------------------------------------------------------------ */ + +static int dmabuf_imp_release(struct gntdev_priv *priv, u32 fd) +{ + return 0; +} + +static struct xen_dmabuf * +dmabuf_imp_to_refs(struct gntdev_priv *priv, int fd, int count, int domid) +{ + return ERR_PTR(-ENOMEM); +} + +/* ------------------------------------------------------------------ */ +/* DMA buffer IOCTL support. */ +/* ------------------------------------------------------------------ */ + +static long +gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_exp_from_refs __user *u) +{ + struct ioctl_gntdev_dmabuf_exp_from_refs op; + u32 *refs; + long ret; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + refs = kcalloc(op.count, sizeof(*refs), GFP_KERNEL); + if (!refs) + return -ENOMEM; + + if (copy_from_user(refs, u->refs, sizeof(*refs) * op.count) != 0) { + ret = -EFAULT; + goto out; + } + + ret = dmabuf_exp_from_refs(priv, op.flags, op.count, + op.domid, refs, &op.fd); + if (ret) + goto out; + + if (copy_to_user(u, &op, sizeof(op)) != 0) + ret = -EFAULT; + +out: + kfree(refs); + return ret; +} + +static long +gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_exp_wait_released __user *u) +{ + struct ioctl_gntdev_dmabuf_exp_wait_released op; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + return dmabuf_exp_wait_released(priv, op.fd, op.wait_to_ms); +} + +static long +gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_imp_to_refs __user *u) +{ + struct ioctl_gntdev_dmabuf_imp_to_refs op; + struct xen_dmabuf *xen_dmabuf; + long ret; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + xen_dmabuf = dmabuf_imp_to_refs(priv, op.fd, op.count, op.domid); + if (IS_ERR(xen_dmabuf)) + return PTR_ERR(xen_dmabuf); + + if (copy_to_user(u->refs, xen_dmabuf->u.imp.refs, + sizeof(*u->refs) * op.count) != 0) { + ret = -EFAULT; + goto out_release; + } + return 0; + +out_release: + dmabuf_imp_release(priv, op.fd); + return ret; +} + +static long +gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv, + struct ioctl_gntdev_dmabuf_imp_release __user *u) +{ + struct ioctl_gntdev_dmabuf_imp_release op; + + if (copy_from_user(&op, u, sizeof(op)) != 0) + return -EFAULT; + + return dmabuf_imp_release(priv, op.fd); +} +#endif + static long gntdev_ioctl(struct file *flip, unsigned int cmd, unsigned long arg) { @@ -1058,6 +1192,20 @@ static long gntdev_ioctl(struct file *flip, case IOCTL_GNTDEV_GRANT_COPY: return gntdev_ioctl_grant_copy(priv, ptr); +#ifdef CONFIG_XEN_GNTDEV_DMABUF + case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: + return gntdev_ioctl_dmabuf_exp_from_refs(priv, ptr); + + case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: + return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); + + case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: + return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); + + case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: + return gntdev_ioctl_dmabuf_imp_release(priv, ptr); +#endif + default: pr_debug("priv %p, unknown cmd %x\n", priv, cmd); return -ENOIOCTLCMD; diff --git a/include/uapi/xen/gntdev.h b/include/uapi/xen/gntdev.h index 2d5a4672f07c..568d5cb522e9 100644 --- a/include/uapi/xen/gntdev.h +++ b/include/uapi/xen/gntdev.h @@ -5,6 +5,7 @@ * Interface to /dev/xen/gntdev. * * Copyright (c) 2007, D G Murray + * Copyright (c) 2018, Oleksandr Andrushchenko, EPAM Systems Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 @@ -215,4 +216,94 @@ struct ioctl_gntdev_grant_copy { */ #define GNTDEV_DMA_FLAG_COHERENT (1 << 2) +/* + * Create a dma-buf [1] from grant references @refs of count @count provided + * by the foreign domain @domid with flags @flags. + * + * By default dma-buf is backed by system memory pages, but by providing + * one of the GNTDEV_DMA_FLAG_XXX flags it can also be created as + * a DMA write-combine or coherent buffer, e.g. allocated with dma_alloc_wc/ + * dma_alloc_coherent. + * + * Returns 0 if dma-buf was successfully created and the corresponding + * dma-buf's file descriptor is returned in @fd. + * + * [1] https://elixir.bootlin.com/linux/latest/source/Documentation/driver-api/dma-buf.rst + */ + +#define IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS \ + _IOC(_IOC_NONE, 'G', 9, \ + sizeof(struct ioctl_gntdev_dmabuf_exp_from_refs)) +struct ioctl_gntdev_dmabuf_exp_from_refs { + /* IN parameters. */ + /* Specific options for this dma-buf: see GNTDEV_DMA_FLAG_XXX. */ + __u32 flags; + /* Number of grant references in @refs array. */ + __u32 count; + /* OUT parameters. */ + /* File descriptor of the dma-buf. */ + __u32 fd; + /* The domain ID of the grant references to be mapped. */ + __u32 domid; + /* Variable IN parameter. */ + /* Array of grant references of size @count. */ + __u32 refs[1]; +}; + +/* + * This will block until the dma-buf with the file descriptor @fd is + * released. This is only valid for buffers created with + * IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS. + * + * If within @wait_to_ms milliseconds the buffer is not released + * then -ETIMEDOUT error is returned. + * If the buffer with the file descriptor @fd does not exist or has already + * been released, then -ENOENT is returned. For valid file descriptors + * this must not be treated as error. + */ +#define IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED \ + _IOC(_IOC_NONE, 'G', 10, \ + sizeof(struct ioctl_gntdev_dmabuf_exp_wait_released)) +struct ioctl_gntdev_dmabuf_exp_wait_released { + /* IN parameters */ + __u32 fd; + __u32 wait_to_ms; +}; + +/* + * Import a dma-buf with file descriptor @fd and export granted references + * to the pages of that dma-buf into array @refs of size @count. + */ +#define IOCTL_GNTDEV_DMABUF_IMP_TO_REFS \ + _IOC(_IOC_NONE, 'G', 11, \ + sizeof(struct ioctl_gntdev_dmabuf_imp_to_refs)) +struct ioctl_gntdev_dmabuf_imp_to_refs { + /* IN parameters. */ + /* File descriptor of the dma-buf. */ + __u32 fd; + /* Number of grant references in @refs array. */ + __u32 count; + /* The domain ID for which references to be granted. */ + __u32 domid; + /* Reserved - must be zero. */ + __u32 reserved; + /* OUT parameters. */ + /* Array of grant references of size @count. */ + __u32 refs[1]; +}; + +/* + * This will close all references to the imported buffer with file descriptor + * @fd, so it can be released by the owner. This is only valid for buffers + * created with IOCTL_GNTDEV_DMABUF_IMP_TO_REFS. + */ +#define IOCTL_GNTDEV_DMABUF_IMP_RELEASE \ + _IOC(_IOC_NONE, 'G', 12, \ + sizeof(struct ioctl_gntdev_dmabuf_imp_release)) +struct ioctl_gntdev_dmabuf_imp_release { + /* IN parameters */ + __u32 fd; + __u32 reserved; +}; + #endif /* __LINUX_PUBLIC_GNTDEV_H__ */