[ Upstream commit 80fc671bcc0173836e9032b0c698ea74c13b9d7c ]
The uacce driver must deal with a possible removal of the parent device
or parent driver module rmmod at any time.
Although uacce_remove(), called on device removal and on driver unbind,
prevents future use of the uacce fops by removing the cdev, fops that
were called before that point may still be running.
Serialize uacce_fops_open() and uacce_remove() with uacce->mutex.
Serialize other fops against uacce_remove() with q->mutex.
Since we need to protect uacce_fops_poll() which gets called on the fast
path, replace uacce->queues_lock with q->mutex to improve scalability.
The other fops are only used during setup.
uacce_queue_is_valid(), checked under q->mutex or uacce->mutex, denotes
whether uacce_remove() has disabled all queues. If that is the case,
don't go any further since the parent device is being removed and
uacce->ops should not be called anymore.
Reported-by: Yang Shen <shenyang39@huawei.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20220701034843.7502-1-zhangfei.gao@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
When uacce parent device module is removed, user app may
still keep the mmaped area, which can be accessed unsafely.
When rmmod, Parent device driver will call uacce_remove,
which unmap all remaining mapping from user space for safety.
VM_FAULT_SIGBUS is also reported to user space accordingly.
Suggested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Uacce (Unified/User-space-access-intended Accelerator Framework) targets to
provide Shared Virtual Addressing (SVA) between accelerators and processes.
So accelerator can access any data structure of the main cpu.
This differs from the data sharing between cpu and io device, which share
only data content rather than address.
Since unified address, hardware and user space of process can share the
same virtual address in the communication.
Uacce create a chrdev for every registration, the queue is allocated to
the process when the chrdev is opened. Then the process can access the
hardware resource by interact with the queue file. By mmap the queue
file space to user space, the process can directly put requests to the
hardware without syscall to the kernel space.
The IOMMU core only tracks mm<->device bonds at the moment, because it
only needs to handle IOTLB invalidation and PASID table entries. However
uacce needs a finer granularity since multiple queues from the same
device can be bound to an mm. When the mm exits, all bound queues must
be stopped so that the IOMMU can safely clear the PASID table entry and
reallocate the PASID.
An intermediate struct uacce_mm links uacce devices and queues.
Note that an mm may be bound to multiple devices but an uacce_mm
structure only ever belongs to a single device, because we don't need
anything more complex (if multiple devices are bound to one mm, then
we'll create one uacce_mm for each bond).
uacce_device --+-- uacce_mm --+-- uacce_queue
| '-- uacce_queue
|
'-- uacce_mm --+-- uacce_queue
+-- uacce_queue
'-- uacce_queue
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Kenneth Lee <liguozhu@hisilicon.com>
Signed-off-by: Zaibo Xu <xuzaibo@huawei.com>
Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
