virtio.h: add memory operation for virtio device #541
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CV-Bowen
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lib/include/openamp/virtio.h
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| static inline void *virtio_alloc_buf(struct virtio_device *vdev, | ||
| size_t size, size_t align) | ||
| { | ||
| return vdev->func->alloc_buf(vdev, size, align); |
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Check argumentts:
- vdev -> return -EINVAL if NULL;
- alloc_buf -> function may be not supported, check if it exists first and return -ENXIO if NULL
lib/include/openamp/virtio.h
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| */ | ||
| static inline void virtio_free_buf(struct virtio_device *vdev, void *buf) | ||
| { | ||
| vdev->func->free_buf(vdev, buf); |
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Check argumentts:
- vdev -> return -EINVAL if NULL;
- free_buf -> function may be not supported, check if it exists first and return -ENXIO if NULL
lib/remoteproc/remoteproc_virtio.c
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| return; | ||
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| rpvdev->free_buf(rpvdev, buf); | ||
| } |
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I think you should call the public functions from virtio top layer interface and let it to redirect to vdev specific alloc/free function instead of invoking the dispatch functions directly.
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Thanks for your suggestion, I'm a little confused, my motivation is that different platforms may have different memory management strategies for remoteproc transport layer, so I introduce function rproc_virtio_set_mm_callback() to let the platform set their own share memory allocate and free functions.
Do you mean we should add a memory operations to the virtio device and then we can make different virtio devices implement their own share memory management strategies?
lib/include/openamp/virtio.h
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| /** Free buffer to transport layer heap */ | ||
| void (*free_buf)(struct virtio_device *vdev, void *buf); | ||
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Seems to me that it is not the good place to add these functions
The memory allocation/free is independent from the virtio layer as addressed directly to the transport layer.
The virtio_dispatch is used for communication between the virtio layer and the transport layer
What about a new structure similar to virtio_dispatch ? virtio_mem_ops or a better name...
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Seems better, I will try this, Thanks.
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Done, please review again @arnopo
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This pull request has been marked as a stale pull request because it has been open (more than) 45 days with no activity. |
CV-Bowen
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Buffer management is different for different transport layer: For MMIO transport layer, the buffer can direclty malloced from the gust os heap beacase the hypervisor can access all the memmory own by guest os. For remoteproc transpor layer, the buffer should be malloced from the share memory region to make sure the remote core can access this buffer too. So add memory ops in virtio device to make different transport/device can implement their own share memory management. Signed-off-by: Bowen Wang <[email protected]>
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CV-Bowen
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Hi @CV-Bowen, Your proposal seems reasonable. For your information, in the meantime, there is a working group initiated by ARM around a new Virtio transport called virtio-msg. This group aims to propose a new Virtio transport that should support virtualization and AMP systems. One objective is also to address memory allocation challenges. My current concern with your PR is that Integrating your work now would imply that we probably have two APIs to support or deprecate this one in the short/middle term. We have to discuss with the OpenAMP team to determine the strategy we want. |
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@arnopo Thank you for your reply and waiting for your decisions. |
We discussed the PR in the OpenAMP meeting. The decision is to postpone this PR to the next release to give more time to verify that this approach will also fit the other virtio transports. |
Buffer management is different for different transport layer:
For MMIO transport layer, the buffer can direclty malloced from
the gust os heap beacase the hypervisor can access all the memmory own
by guest os.
For remoteproc transpor layer, the buffer should be malloced from
the share memory region to make sure the remote core can access this
buffer too.
So add memory ops in virtio device to make different transport/device can
implement their own share memory management.