Re: [PATCH v2 1/1] tee: new ioctl to a register tee_shm from a dmabuf file descriptor
From: Christian König
Date: Fri Jan 27 2023 - 06:21:26 EST
Hi guys,
Am 27.01.23 um 11:54 schrieb Olivier Masse:
Hi Joakim,
Hi Etienne,
Let me bring back this pull request for OPTEE Linux driver.
Last feedback was from Christian König and Sumit Garg.
From Christian:
Just two comments:
1. Dmitry is working on a change which renames some functions and
makes
it mandatory to call them with the dma_resv lock held.
Depending on how you want to upstream this change you will certainly
run
into conflicts with that.
Is there any update on these changes ?
Just FYI: The upstream changes Dmitry worked on are now committed, so
you just need to rebase your work on top and send it out once more.
2. Would it be possible to do this dynamically? In other words does
the
tee driver has a concept of buffers moving around?
We do not support dynamic secure memory heap.
That's not an issue. If you pin the memory anyway then you can expose it
pinned through DMA-buf as well.
The only thing you should avoid is pinning it extra for DMA-buf, because
then you often create a really nice possibility for an OOM deny of service.
Regards,
Christian.
From Sumit:
What limits you to extend this feature to non-contiguous memory
buffers? I believe that should be possible with OP-TEE dynamic shared
memory which gives you the granularity to register a list of pages.
Our solution use a fixed protected reserved memory region and do not
rely on a dynamic protection managed in secure.
The scope of this implementation rely on a static memory region handled
by a specific DMA Heap type.
Best regards,
Olivier MASSE
On ven., 2022-08-12 at 16:30 +0200, Olivier Masse wrote:
From: Etienne Carriere <etienne.carriere@xxxxxxxxxx>
This change allows userland to create a tee_shm object that refers
to a dmabuf reference.
Userland provides a dmabuf file descriptor as buffer reference.
The created tee_shm object exported as a brand new dmabuf reference
used to provide a clean fd to userland. Userland shall closed this
new
fd to release the tee_shm object resources. The initial dmabuf
resources
are tracked independently through original dmabuf file descriptor.
Once the buffer is registered and until it is released, TEE driver
keeps a refcount on the registered dmabuf structure.
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_EXT_DMA_BUF. Such tee_shm structures are flagged with
TEE_SHM_EXT_DMA_BUF.
Co-Developed-by: Etienne Carriere <etienne.carriere@xxxxxxxxxx>
Signed-off-by: Olivier Masse <olivier.masse@xxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
From: https://github.com/linaro-swg/linux.git
(cherry picked from commit 41e21e5c405530590dc2dd10b2a8dbe64589840f)
---
drivers/tee/tee_core.c | 38 +++++++++++++++
drivers/tee/tee_shm.c | 99
+++++++++++++++++++++++++++++++++++++++-
include/linux/tee_drv.h | 11 +++++
include/uapi/linux/tee.h | 29 ++++++++++++
4 files changed, 175 insertions(+), 2 deletions(-)
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 8aa1a4836b92..7c45cbf85eb9 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -355,6 +355,42 @@ 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)
@@ -829,6 +865,8 @@ 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 836872467dc6..55a3fbbb022e 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>
@@ -12,6 +13,14 @@
#include <linux/uio.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;
@@ -71,7 +80,16 @@ 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_EXT_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);
@@ -195,7 +213,7 @@ 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)
{
@@ -229,6 +247,83 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct
tee_context *ctx, size_t size)
}
EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_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;
+ }
+
+ 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 = sg_dma_address(ref->sgt->sgl);
+ ref->shm.size = sg_dma_len(ref->sgt->sgl);
+ ref->shm.flags = TEE_SHM_EXT_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);
+
static struct tee_shm *
register_shm_helper(struct tee_context *ctx, unsigned long addr,
size_t length, u32 flags, int id)
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index 911cad324acc..40ddd5376c2d 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_EXT_DMA_BUF BIT(4) /* Memory with dma-buf
handle */
struct device;
struct tee_device;
@@ -276,6 +277,16 @@ struct tee_shm *tee_shm_alloc_kernel_buf(struct
tee_context *ctx, size_t size);
struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
void *addr, size_t length);
+/**
+ * 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);
+
/**
* tee_shm_is_dynamic() - Check if shared memory object is of the
dynamic kind
* @shm: Shared memory handle
diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
index 25a6c534beb1..baf3cd7cfdac 100644
--- a/include/uapi/linux/tee.h
+++ b/include/uapi/linux/tee.h
@@ -121,6 +121,35 @@ 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;
+} __attribute__ ((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