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Message-ID: <CAHUa44HfZ=xT8QFvseR_-e3xhYWQU9kg=Q-wgxN5noXBi_cLbg@mail.gmail.com>
Date: Wed, 4 Sep 2024 11:49:06 +0200
From: Jens Wiklander <jens.wiklander@...aro.org>
To: "T.J. Mercier" <tjmercier@...gle.com>
Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org,
linaro-mm-sig@...ts.linaro.org, op-tee@...ts.trustedfirmware.org,
linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org,
Olivier Masse <olivier.masse@....com>, Thierry Reding <thierry.reding@...il.com>,
Yong Wu <yong.wu@...iatek.com>, Sumit Semwal <sumit.semwal@...aro.org>,
Benjamin Gaignard <benjamin.gaignard@...labora.com>, Brian Starkey <Brian.Starkey@....com>,
John Stultz <jstultz@...gle.com>, Christian König <christian.koenig@....com>,
Sumit Garg <sumit.garg@...aro.org>, Matthias Brugger <matthias.bgg@...il.com>,
AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
Etienne Carriere <etienne.carriere@...aro.org>
Subject: Re: [RFC PATCH 2/4] tee: new ioctl to a register tee_shm from a
dmabuf file descriptor
On Tue, Sep 3, 2024 at 7:50 PM T.J. Mercier <tjmercier@...gle.com> wrote:
>
> On Fri, Aug 30, 2024 at 12:04 AM Jens Wiklander
> <jens.wiklander@...aro.org> wrote:
> >
> > From: Etienne Carriere <etienne.carriere@...aro.org>
> >
> > Enable userspace to create a tee_shm object that refers to a dmabuf
> > reference.
> >
> > Userspace registers the dmabuf file descriptor as in a tee_shm object.
> > The registration is completed with a tee_shm file descriptor returned to
> > userspace.
> >
> > Userspace is free to close the dmabuf file descriptor now since all the
> > resources are now held via the tee_shm object.
> >
> > Closing the tee_shm file descriptor will release all resources used by the
> > tee_shm object.
> >
> > This change only support dmabuf references that relates to physically
> > contiguous memory buffers.
> >
> > New tee_shm flag to identify tee_shm objects built from a registered
> > dmabuf, TEE_SHM_DMA_BUF.
> >
> > Signed-off-by: Etienne Carriere <etienne.carriere@...aro.org>
> > Signed-off-by: Olivier Masse <olivier.masse@....com>
> > Signed-off-by: Jens Wiklander <jens.wiklander@...aro.org>
> > ---
> > drivers/tee/tee_core.c | 38 ++++++++++++++
> > drivers/tee/tee_shm.c | 104 +++++++++++++++++++++++++++++++++++++--
> > include/linux/tee_drv.h | 11 +++++
> > include/uapi/linux/tee.h | 29 +++++++++++
> > 4 files changed, 179 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
> > index e59c20d74b36..3dfd5428d58c 100644
> > --- a/drivers/tee/tee_core.c
> > +++ b/drivers/tee/tee_core.c
> > @@ -356,6 +356,42 @@ tee_ioctl_shm_register(struct tee_context *ctx,
> > return ret;
> > }
> >
> > +static int tee_ioctl_shm_register_fd(struct tee_context *ctx,
> > + struct tee_ioctl_shm_register_fd_data __user *udata)
> > +{
> > + struct tee_ioctl_shm_register_fd_data data;
> > + struct tee_shm *shm;
> > + long ret;
> > +
> > + if (copy_from_user(&data, udata, sizeof(data)))
> > + return -EFAULT;
> > +
> > + /* Currently no input flags are supported */
> > + if (data.flags)
> > + return -EINVAL;
> > +
> > + shm = tee_shm_register_fd(ctx, data.fd);
> > + if (IS_ERR(shm))
> > + return -EINVAL;
> > +
> > + data.id = shm->id;
> > + data.flags = shm->flags;
> > + data.size = shm->size;
> > +
> > + if (copy_to_user(udata, &data, sizeof(data)))
> > + ret = -EFAULT;
> > + else
> > + ret = tee_shm_get_fd(shm);
> > +
> > + /*
> > + * When user space closes the file descriptor the shared memory
> > + * should be freed or if tee_shm_get_fd() failed then it will
> > + * be freed immediately.
> > + */
> > + tee_shm_put(shm);
> > + return ret;
> > +}
> > +
> > static int params_from_user(struct tee_context *ctx, struct tee_param *params,
> > size_t num_params,
> > struct tee_ioctl_param __user *uparams)
> > @@ -830,6 +866,8 @@ static long tee_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> > return tee_ioctl_shm_alloc(ctx, uarg);
> > case TEE_IOC_SHM_REGISTER:
> > return tee_ioctl_shm_register(ctx, uarg);
> > + case TEE_IOC_SHM_REGISTER_FD:
> > + return tee_ioctl_shm_register_fd(ctx, uarg);
> > case TEE_IOC_OPEN_SESSION:
> > return tee_ioctl_open_session(ctx, uarg);
> > case TEE_IOC_INVOKE:
> > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> > index 731d9028b67f..a1cb3c8b6423 100644
> > --- a/drivers/tee/tee_shm.c
> > +++ b/drivers/tee/tee_shm.c
> > @@ -4,6 +4,7 @@
> > */
> > #include <linux/anon_inodes.h>
> > #include <linux/device.h>
> > +#include <linux/dma-buf.h>
> > #include <linux/idr.h>
> > #include <linux/mm.h>
> > #include <linux/sched.h>
> > @@ -14,6 +15,14 @@
> > #include <linux/highmem.h>
> > #include "tee_private.h"
> >
> > +/* extra references appended to shm object for registered shared memory */
> > +struct tee_shm_dmabuf_ref {
> > + struct tee_shm shm;
> > + struct dma_buf *dmabuf;
> > + struct dma_buf_attachment *attach;
> > + struct sg_table *sgt;
> > +};
> > +
> > static void shm_put_kernel_pages(struct page **pages, size_t page_count)
> > {
> > size_t n;
> > @@ -44,7 +53,16 @@ static void release_registered_pages(struct tee_shm *shm)
> >
> > static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
> > {
> > - if (shm->flags & TEE_SHM_POOL) {
> > + if (shm->flags & TEE_SHM_DMA_BUF) {
> > + struct tee_shm_dmabuf_ref *ref;
> > +
> > + ref = container_of(shm, struct tee_shm_dmabuf_ref, shm);
> > + dma_buf_unmap_attachment(ref->attach, ref->sgt,
> > + DMA_BIDIRECTIONAL);
> > +
> > + dma_buf_detach(ref->dmabuf, ref->attach);
> > + dma_buf_put(ref->dmabuf);
> > + } else if (shm->flags & TEE_SHM_POOL) {
> > teedev->pool->ops->free(teedev->pool, shm);
> > } else if (shm->flags & TEE_SHM_DYNAMIC) {
> > int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
> > @@ -56,7 +74,8 @@ static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
> > release_registered_pages(shm);
> > }
> >
> > - teedev_ctx_put(shm->ctx);
> > + if (shm->ctx)
> > + teedev_ctx_put(shm->ctx);
> >
> > kfree(shm);
> >
> > @@ -168,7 +187,7 @@ struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t size)
> > * tee_client_invoke_func(). The memory allocated is later freed with a
> > * call to tee_shm_free().
> > *
> > - * @returns a pointer to 'struct tee_shm'
> > + * @returns a pointer to 'struct tee_shm' on success, and ERR_PTR on failure
> > */
> > struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
> > {
> > @@ -178,6 +197,85 @@ struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
> > }
> > EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
> >
> > +struct tee_shm *tee_shm_register_fd(struct tee_context *ctx, int fd)
> > +{
> > + struct tee_shm_dmabuf_ref *ref;
> > + int rc;
> > +
> > + if (!tee_device_get(ctx->teedev))
> > + return ERR_PTR(-EINVAL);
> > +
> > + teedev_ctx_get(ctx);
> > +
> > + ref = kzalloc(sizeof(*ref), GFP_KERNEL);
> > + if (!ref) {
> > + rc = -ENOMEM;
> > + goto err_put_tee;
> > + }
> > +
> > + refcount_set(&ref->shm.refcount, 1);
> > + ref->shm.ctx = ctx;
> > + ref->shm.id = -1;
> > +
> > + ref->dmabuf = dma_buf_get(fd);
> > + if (IS_ERR(ref->dmabuf)) {
> > + rc = PTR_ERR(ref->dmabuf);
> > + goto err_put_dmabuf;
> > + }
>
> Hi,
>
> Most of the gotos in the errors paths from here on look offset by one
> to me. Attempting to put a dmabuf after failing to get, detaching
> after failing to attach, unmapping after failing to map, removing an
> IDR after failing to allocate one.
You're right, I'll fix them.
Thanks,
Jens
>
>
> > +
> > + ref->attach = dma_buf_attach(ref->dmabuf, &ref->shm.ctx->teedev->dev);
> > + if (IS_ERR(ref->attach)) {
> > + rc = PTR_ERR(ref->attach);
> > + goto err_detach;
> > + }
> > +
> > + ref->sgt = dma_buf_map_attachment(ref->attach, DMA_BIDIRECTIONAL);
> > + if (IS_ERR(ref->sgt)) {
> > + rc = PTR_ERR(ref->sgt);
> > + goto err_unmap_attachement;
> > + }
> > +
> > + if (sg_nents(ref->sgt->sgl) != 1) {
> > + rc = PTR_ERR(ref->sgt->sgl);
> > + goto err_unmap_attachement;
> > + }
> > +
> > + ref->shm.paddr = page_to_phys(sg_page(ref->sgt->sgl));
> > + ref->shm.size = ref->sgt->sgl->length;
> > + ref->shm.flags = TEE_SHM_DMA_BUF;
> > +
> > + mutex_lock(&ref->shm.ctx->teedev->mutex);
> > + ref->shm.id = idr_alloc(&ref->shm.ctx->teedev->idr, &ref->shm,
> > + 1, 0, GFP_KERNEL);
> > + mutex_unlock(&ref->shm.ctx->teedev->mutex);
> > + if (ref->shm.id < 0) {
> > + rc = ref->shm.id;
> > + goto err_idr_remove;
> > + }
> > +
> > + return &ref->shm;
> > +
> > +err_idr_remove:
> > + mutex_lock(&ctx->teedev->mutex);
> > + idr_remove(&ctx->teedev->idr, ref->shm.id);
> > + mutex_unlock(&ctx->teedev->mutex);
> > +err_unmap_attachement:
> > + dma_buf_unmap_attachment(ref->attach, ref->sgt, DMA_BIDIRECTIONAL);
> > +err_detach:
> > + dma_buf_detach(ref->dmabuf, ref->attach);
> > +err_put_dmabuf:
> > + dma_buf_put(ref->dmabuf);
> > + kfree(ref);
> > +err_put_tee:
> > + teedev_ctx_put(ctx);
> > + tee_device_put(ctx->teedev);
> > +
> > + return ERR_PTR(rc);
> > +}
> > +EXPORT_SYMBOL_GPL(tee_shm_register_fd);
> > +
> > +
> > +
> > /**
> > * tee_shm_alloc_priv_buf() - Allocate shared memory for a privately shared
> > * kernel buffer
> > diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> > index 71632e3c5f18..6a1fee689007 100644
> > --- a/include/linux/tee_drv.h
> > +++ b/include/linux/tee_drv.h
> > @@ -25,6 +25,7 @@
> > #define TEE_SHM_USER_MAPPED BIT(1) /* Memory mapped in user space */
> > #define TEE_SHM_POOL BIT(2) /* Memory allocated from pool */
> > #define TEE_SHM_PRIV BIT(3) /* Memory private to TEE driver */
> > +#define TEE_SHM_DMA_BUF BIT(4) /* Memory with dma-buf handle */
> >
> > struct device;
> > struct tee_device;
> > @@ -275,6 +276,16 @@ void *tee_get_drvdata(struct tee_device *teedev);
> > struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size);
> > struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size);
> >
> > +/**
> > + * tee_shm_register_fd() - Register shared memory from file descriptor
> > + *
> > + * @ctx: Context that allocates the shared memory
> > + * @fd: Shared memory file descriptor reference
> > + *
> > + * @returns a pointer to 'struct tee_shm' on success, and ERR_PTR on failure
> > + */
> > +struct tee_shm *tee_shm_register_fd(struct tee_context *ctx, int fd);
> > +
> > struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
> > void *addr, size_t length);
> >
> > diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
> > index 23e57164693c..77bc8ef24d3c 100644
> > --- a/include/uapi/linux/tee.h
> > +++ b/include/uapi/linux/tee.h
> > @@ -117,6 +117,35 @@ struct tee_ioctl_shm_alloc_data {
> > #define TEE_IOC_SHM_ALLOC _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 1, \
> > struct tee_ioctl_shm_alloc_data)
> >
> > +/**
> > + * struct tee_ioctl_shm_register_fd_data - Shared memory registering argument
> > + * @fd: [in] File descriptor identifying the shared memory
> > + * @size: [out] Size of shared memory to allocate
> > + * @flags: [in] Flags to/from allocation.
> > + * @id: [out] Identifier of the shared memory
> > + *
> > + * The flags field should currently be zero as input. Updated by the call
> > + * with actual flags as defined by TEE_IOCTL_SHM_* above.
> > + * This structure is used as argument for TEE_IOC_SHM_REGISTER_FD below.
> > + */
> > +struct tee_ioctl_shm_register_fd_data {
> > + __s64 fd;
> > + __u64 size;
> > + __u32 flags;
> > + __s32 id;
> > +} __aligned(8);
> > +
> > +/**
> > + * TEE_IOC_SHM_REGISTER_FD - register a shared memory from a file descriptor
> > + *
> > + * Returns a file descriptor on success or < 0 on failure
> > + *
> > + * The returned file descriptor refers to the shared memory object in kernel
> > + * land. The shared memory is freed when the descriptor is closed.
> > + */
> > +#define TEE_IOC_SHM_REGISTER_FD _IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 8, \
> > + struct tee_ioctl_shm_register_fd_data)
> > +
> > /**
> > * struct tee_ioctl_buf_data - Variable sized buffer
> > * @buf_ptr: [in] A __user pointer to a buffer
> > --
> > 2.34.1
> >
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