From: Oded Gabbay <ogabbay@kernel.org>
To: linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, jgg@ziepe.ca
Cc: christian.koenig@amd.com, daniel.vetter@ffwll.ch,
galpress@amazon.com, sleybo@amazon.com,
dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org,
linux-media@vger.kernel.org, dledford@redhat.com,
airlied@gmail.com, alexander.deucher@amd.com, leonro@nvidia.com,
hch@lst.de, amd-gfx@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org
Subject: [PATCH v6 1/2] habanalabs: define uAPI to export FD for DMA-BUF
Date: Sun, 12 Sep 2021 19:53:08 +0300 [thread overview]
Message-ID: <20210912165309.98695-2-ogabbay@kernel.org> (raw)
In-Reply-To: <20210912165309.98695-1-ogabbay@kernel.org>
User process might want to share the device memory with another
driver/device, and to allow it to access it over PCIe (P2P).
To enable this, we utilize the dma-buf mechanism and add a dma-buf
exporter support, so the other driver can import the device memory and
access it.
The device memory is allocated using our existing allocation uAPI,
where the user will get a handle that represents the allocation.
The user will then need to call the new
uAPI (HL_MEM_OP_EXPORT_DMABUF_FD) and give the handle as a parameter.
The driver will return a FD that represents the DMA-BUF object that
was created to match that allocation.
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/uapi/misc/habanalabs.h | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/include/uapi/misc/habanalabs.h b/include/uapi/misc/habanalabs.h
index 042e96f99d85..b1def68bf5d3 100644
--- a/include/uapi/misc/habanalabs.h
+++ b/include/uapi/misc/habanalabs.h
@@ -960,6 +960,10 @@ union hl_wait_cs_args {
#define HL_MEM_OP_UNMAP 3
/* Opcode to map a hw block */
#define HL_MEM_OP_MAP_BLOCK 4
+/* Opcode to create DMA-BUF object for an existing device memory allocation
+ * and to export an FD of that DMA-BUF back to the caller
+ */
+#define HL_MEM_OP_EXPORT_DMABUF_FD 5
/* Memory flags */
#define HL_MEM_CONTIGUOUS 0x1
@@ -1031,11 +1035,26 @@ struct hl_mem_in {
/* Virtual address returned from HL_MEM_OP_MAP */
__u64 device_virt_addr;
} unmap;
+
+ /* HL_MEM_OP_EXPORT_DMABUF_FD */
+ struct {
+ /* Handle returned from HL_MEM_OP_ALLOC. In Gaudi,
+ * where we don't have MMU for the device memory, the
+ * driver expects a physical address (instead of
+ * a handle) in the device memory space.
+ */
+ __u64 handle;
+ /* Size of memory allocation. Relevant only for GAUDI */
+ __u64 mem_size;
+ } export_dmabuf_fd;
};
/* HL_MEM_OP_* */
__u32 op;
- /* HL_MEM_* flags */
+ /* HL_MEM_* flags.
+ * For the HL_MEM_OP_EXPORT_DMABUF_FD opcode, this field holds the
+ * DMA-BUF file/FD flags.
+ */
__u32 flags;
/* Context ID - Currently not in use */
__u32 ctx_id;
@@ -1072,6 +1091,13 @@ struct hl_mem_out {
__u32 pad;
};
+
+ /* Returned in HL_MEM_OP_EXPORT_DMABUF_FD. Represents the
+ * DMA-BUF object that was created to describe a memory
+ * allocation on the device's memory space. The FD should be
+ * passed to the importer driver
+ */
+ __u64 fd;
};
};
--
2.17.1
next prev parent reply other threads:[~2021-09-12 16:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-12 16:53 [PATCH v6 0/2] Add p2p via dmabuf to habanalabs Oded Gabbay
2021-09-12 16:53 ` Oded Gabbay [this message]
2021-09-28 17:13 ` [PATCH v6 1/2] habanalabs: define uAPI to export FD for DMA-BUF Jason Gunthorpe
2021-09-28 19:12 ` Oded Gabbay
2021-09-12 16:53 ` [PATCH v6 2/2] habanalabs: add support for dma-buf exporter Oded Gabbay
2021-09-28 17:36 ` Jason Gunthorpe
2021-09-28 21:17 ` Oded Gabbay
2021-09-30 12:46 ` Oded Gabbay
2021-10-01 14:52 ` Jason Gunthorpe
2021-10-01 14:50 ` Jason Gunthorpe
2021-09-14 14:18 ` [PATCH v6 0/2] Add p2p via dmabuf to habanalabs Daniel Vetter
2021-09-14 14:58 ` Oded Gabbay
2021-09-14 16:12 ` Jason Gunthorpe
2021-09-15 7:45 ` Oded Gabbay
2021-09-16 12:31 ` Daniel Vetter
2021-09-16 12:44 ` Oded Gabbay
2021-09-16 13:16 ` Oded Gabbay
2021-09-17 12:25 ` Daniel Vetter
2021-09-16 13:10 ` Jason Gunthorpe
2021-09-17 12:30 ` Daniel Vetter
2021-09-18 8:38 ` Oded Gabbay
2021-09-23 9:22 ` Oded Gabbay
2021-09-28 7:04 ` Oded Gabbay
2021-09-30 9:13 ` Daniel Vetter
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