Am 05.09.24 um 08:56 schrieb Jens Wiklander:
On Fri, Aug 30, 2024 at 10:47 AM Christian König
<christian.koenig@xxxxxxx> wrote:
Am 30.08.24 um 09:03 schrieb Jens Wiklander:
Add a no_map attribute to struct restricted_heap_attachment and struct
restricted_heap to skip the call to dma_map_sgtable() if set. This
avoids trying to map a dma-buf that doens't refer to memory accessible
by the kernel.
You seem to have a misunderstanding here dma_map_sgtable() is called to
map a table into IOMMU and not any kernel address space.
So please explain why you need that?
You're right, I had misunderstood dma_map_sgtable(). There's no need
for the no_map attribute, so I'll remove it.
Perhaps you have a suggestion on how to fix a problem when using
dma_map_sgtable()?
Without it, I'll have to assign a pointer to teedev->dev.dma_mask when
using the restricted heap with the OP-TEE driver or there will be a
warning in __dma_map_sg_attrs() ending with a failure when trying to
register the dma-buf fd. OP-TEE is probed with a platform device, and
taking the dma_mask pointer from that device works. Is that a good
approach or is there a better way of assigning dma_mask?
Mhm, I don't know the full picture so I have to make some assumptions.
The teedev is just a virtual device which represents the restricted
memory access paths of a real device?
If that is true then taking the dma-mask from the real device is most
likely the right thing to do.
Regards,
Christian.
Thanks,
Jens
Regards,
Christian.
Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
---
drivers/dma-buf/heaps/restricted_heap.c | 17 +++++++++++++----
drivers/dma-buf/heaps/restricted_heap.h | 2 ++
2 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/dma-buf/heaps/restricted_heap.c b/drivers/dma-buf/heaps/restricted_heap.c
index 8bc8a5e3f969..4bf28e3727ca 100644
--- a/drivers/dma-buf/heaps/restricted_heap.c
+++ b/drivers/dma-buf/heaps/restricted_heap.c
@@ -16,6 +16,7 @@
struct restricted_heap_attachment {
struct sg_table *table;
struct device *dev;
+ bool no_map;
};
static int
@@ -54,6 +55,8 @@ restricted_heap_memory_free(struct restricted_heap *rheap, struct restricted_buf
static int restricted_heap_attach(struct dma_buf *dmabuf, struct dma_buf_attachment *attachment)
{
struct restricted_buffer *restricted_buf = dmabuf->priv;
+ struct dma_heap *heap = restricted_buf->heap;
+ struct restricted_heap *rheap = dma_heap_get_drvdata(heap);
struct restricted_heap_attachment *a;
struct sg_table *table;
@@ -70,6 +73,7 @@ static int restricted_heap_attach(struct dma_buf *dmabuf, struct dma_buf_attachm
sg_dma_mark_restricted(table->sgl);
a->table = table;
a->dev = attachment->dev;
+ a->no_map = rheap->no_map;
attachment->priv = a;
return 0;
@@ -92,9 +96,12 @@ restricted_heap_map_dma_buf(struct dma_buf_attachment *attachment,
struct sg_table *table = a->table;
int ret;
- ret = dma_map_sgtable(attachment->dev, table, direction, DMA_ATTR_SKIP_CPU_SYNC);
- if (ret)
- return ERR_PTR(ret);
+ if (!a->no_map) {
+ ret = dma_map_sgtable(attachment->dev, table, direction,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ if (ret)
+ return ERR_PTR(ret);
+ }
return table;
}
@@ -106,7 +113,9 @@ restricted_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_t
WARN_ON(a->table != table);
- dma_unmap_sgtable(attachment->dev, table, direction, DMA_ATTR_SKIP_CPU_SYNC);
+ if (!a->no_map)
+ dma_unmap_sgtable(attachment->dev, table, direction,
+ DMA_ATTR_SKIP_CPU_SYNC);
}
static int
diff --git a/drivers/dma-buf/heaps/restricted_heap.h b/drivers/dma-buf/heaps/restricted_heap.h
index 7dec4b8a471b..94cc0842f70d 100644
--- a/drivers/dma-buf/heaps/restricted_heap.h
+++ b/drivers/dma-buf/heaps/restricted_heap.h
@@ -27,6 +27,8 @@ struct restricted_heap {
unsigned long cma_paddr;
unsigned long cma_size;
+ bool no_map;
+
void *priv_data;
};
