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Message-ID: <797a2cbd-ab84-47ec-99b0-23c392f343e1@xs4all.nl>
Date: Mon, 11 Dec 2023 11:45:43 +0100
From: Hans Verkuil <hverkuil-cisco@...all.nl>
To: Yunfei Dong <yunfei.dong@...iatek.com>,
Jeffrey Kardatzke <jkardatzke@...gle.com>,
Nícolas F . R . A . Prado
<nfraprado@...labora.com>,
Nicolas Dufresne <nicolas.dufresne@...labora.com>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>,
Benjamin Gaignard <benjamin.gaignard@...labora.com>,
Nathan Hebert <nhebert@...omium.org>
Cc: Chen-Yu Tsai <wenst@...omium.org>, Yong Wu <yong.wu@...iatek.com>,
Hsin-Yi Wang <hsinyi@...omium.org>,
Fritz Koenig <frkoenig@...omium.org>,
Daniel Vetter <daniel@...ll.ch>,
Steve Cho <stevecho@...omium.org>,
Sumit Semwal <sumit.semwal@...aro.org>,
Brian Starkey <Brian.Starkey@....com>,
John Stultz <jstultz@...gle.com>,
"T . J . Mercier" <tjmercier@...gle.com>,
Christian König <christian.koenig@....com>,
Matthias Brugger <matthias.bgg@...il.com>,
dri-devel@...ts.freedesktop.org, linaro-mm-sig@...ts.linaro.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org,
Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH v3,02/21] v4l2: handle secure memory flags in queue setup
Hi Yunfei, Jeffrey,
Some comments below:
On 06/12/2023 09:15, Yunfei Dong wrote:
> From: Jeffrey Kardatzke <jkardatzke@...gle.com>
>
> Validates the secure memory flags when setting up a queue and ensures
> the queue has the proper capability.
>
> Signed-off-by: Jeffrey Kardatzke <jkardatzke@...gle.com>
> Signed-off-by: Yunfei Dong <yunfei.dong@...iatek.com>
> ---
> .../media/common/videobuf2/videobuf2-core.c | 23 +++++++++++++
> .../media/common/videobuf2/videobuf2-v4l2.c | 34 +++++++++++++------
> 2 files changed, 46 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 8c1df829745b..09dc030484be 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -813,6 +813,15 @@ static bool verify_coherency_flags(struct vb2_queue *q, bool non_coherent_mem)
> return true;
> }
>
> +static bool verify_secure_mem_flags(struct vb2_queue *q, bool secure_mem)
> +{
> + if (secure_mem != q->secure_mem) {
> + dprintk(q, 1, "secure memory model mismatch\n");
> + return false;
> + }
> + return true;
> +}
> +
> int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> unsigned int flags, unsigned int *count)
> {
> @@ -820,6 +829,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> unsigned int q_num_bufs = vb2_get_num_buffers(q);
> unsigned plane_sizes[VB2_MAX_PLANES] = { };
> bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
> + bool secure_mem = flags & V4L2_MEMORY_FLAG_SECURE;
> unsigned int i;
> int ret = 0;
>
> @@ -836,6 +846,8 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> if (*count == 0 || q_num_bufs != 0 ||
> (q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory) ||
> !verify_coherency_flags(q, non_coherent_mem)) {
> + bool no_previous_buffers = !q->num_buffers;
> +
> /*
> * We already have buffers allocated, so first check if they
> * are not in use and can be freed.
> @@ -854,6 +866,12 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> __vb2_queue_free(q, q_num_bufs);
> mutex_unlock(&q->mmap_lock);
>
> + /*
> + * Do not allow switching secure buffer mode.
> + */
> + if (!no_previous_buffers && !verify_secure_mem_flags(q, secure_mem))
> + return -EINVAL;
> +
Why is this needed? Here VIDIOC_REQBUFS is called either to just delete
all existing buffers (count == 0), or to delete all existing buffers and
allocate new buffers (count > 0).
Since in both cases all existing buffers are deleted, you are free to choose
whatever new secure mode you want.
> /*
> * In case of REQBUFS(0) return immediately without calling
> * driver's queue_setup() callback and allocating resources.
> @@ -882,6 +900,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> if (ret)
> return ret;
> set_queue_coherency(q, non_coherent_mem);
> + q->secure_mem = secure_mem;
>
> /*
> * Ask the driver how many buffers and planes per buffer it requires.
> @@ -986,6 +1005,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> unsigned plane_sizes[VB2_MAX_PLANES] = { };
> bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
> unsigned int q_num_bufs = vb2_get_num_buffers(q);
> + bool secure_mem = flags & V4L2_MEMORY_FLAG_SECURE;
> bool no_previous_buffers = !q_num_bufs;
> int ret = 0;
>
> @@ -1015,6 +1035,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> return ret;
> q->waiting_for_buffers = !q->is_output;
> set_queue_coherency(q, non_coherent_mem);
> + q->secure_mem = secure_mem;
> } else {
> if (q->memory != memory) {
> dprintk(q, 1, "memory model mismatch\n");
> @@ -1022,6 +1043,8 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> }
> if (!verify_coherency_flags(q, non_coherent_mem))
> return -EINVAL;
> + if (!verify_secure_mem_flags(q, secure_mem))
> + return -EINVAL;
> }
>
> num_buffers = min(*count, q->max_num_buffers - q_num_bufs);
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 54d572c3b515..0a530830276c 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -686,22 +686,30 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
> *caps |= V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS;
> if (q->supports_requests)
> *caps |= V4L2_BUF_CAP_SUPPORTS_REQUESTS;
> + if (q->allow_secure_mem && q->io_modes & VB2_DMABUF)
> + *caps |= V4L2_BUF_CAP_SUPPORTS_SECURE_MEM;
> }
>
> -static void validate_memory_flags(struct vb2_queue *q,
> +static bool validate_memory_flags(struct vb2_queue *q,
> int memory,
> u32 *flags)
> {
> + if (*flags & V4L2_MEMORY_FLAG_SECURE &&
> + (!q->allow_secure_mem || memory != V4L2_MEMORY_DMABUF)) {
> + return false;
> + }
> +
This check belongs to videobuf2-core.c and the check should be done
in vb2_core_reqbufs and vb2_core_create_bufs.
So just leave this function as a void.
> if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP) {
> /*
> - * This needs to clear V4L2_MEMORY_FLAG_NON_COHERENT only,
> - * but in order to avoid bugs we zero out all bits.
> + * This needs to clear V4L2_MEMORY_FLAG_NON_COHERENT only.
Just drop this as well since it adds no useful information anymore.
> */
> - *flags = 0;
> - } else {
> - /* Clear all unknown flags. */
> - *flags &= V4L2_MEMORY_FLAG_NON_COHERENT;
> + *flags &= ~V4L2_MEMORY_FLAG_NON_COHERENT;
> }
> +
> + /* Clear all unknown flags. */
> + *flags &= V4L2_MEMORY_FLAG_NON_COHERENT | V4L2_MEMORY_FLAG_SECURE;
This is still needed here.
> +
> + return true;
> }
>
So the following changes from here...
> int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
> @@ -710,7 +718,8 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
> u32 flags = req->flags;
>
> fill_buf_caps(q, &req->capabilities);
> - validate_memory_flags(q, req->memory, &flags);
> + if (!validate_memory_flags(q, req->memory, &flags))
> + return -EINVAL;
> req->flags = flags;
> return ret ? ret : vb2_core_reqbufs(q, req->memory,
> req->flags, &req->count);
> @@ -752,7 +761,8 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> unsigned i;
>
> fill_buf_caps(q, &create->capabilities);
> - validate_memory_flags(q, create->memory, &create->flags);
> + if (!validate_memory_flags(q, create->memory, &create->flags))
> + return -EINVAL;
> create->index = vb2_get_num_buffers(q);
> create->max_num_buffers = q->max_num_buffers;
> create->capabilities |= V4L2_BUF_CAP_SUPPORTS_MAX_NUM_BUFFERS;
> @@ -1007,7 +1017,8 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
> u32 flags = p->flags;
>
> fill_buf_caps(vdev->queue, &p->capabilities);
> - validate_memory_flags(vdev->queue, p->memory, &flags);
> + if (!validate_memory_flags(vdev->queue, p->memory, &flags))
> + return -EINVAL;
> p->flags = flags;
> if (res)
> return res;
> @@ -1031,7 +1042,8 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
>
> p->index = vdev->queue->num_buffers;
> fill_buf_caps(vdev->queue, &p->capabilities);
> - validate_memory_flags(vdev->queue, p->memory, &p->flags);
> + if (!validate_memory_flags(vdev->queue, p->memory, &p->flags))
> + return -EINVAL;
> /*
> * If count == 0, then just check if memory and type are valid.
> * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
...to the end should all be dropped since the vb2 core will do the checks.
Regards,
Hans
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