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121 lines
4.3 KiB
121 lines
4.3 KiB
/* |
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* Copyright © 2015 Intel Corporation. |
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* |
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* Authors: David Woodhouse <David.Woodhouse@intel.com> |
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* |
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* This program is free software; you can redistribute it and/or modify it |
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* under the terms and conditions of the GNU General Public License, |
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* version 2, as published by the Free Software Foundation. |
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* |
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* This program is distributed in the hope it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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* more details. |
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*/ |
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#ifndef __INTEL_SVM_H__ |
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#define __INTEL_SVM_H__ |
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struct device; |
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struct svm_dev_ops { |
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void (*fault_cb)(struct device *dev, int pasid, u64 address, |
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u32 private, int rwxp, int response); |
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}; |
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/* Values for rxwp in fault_cb callback */ |
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#define SVM_REQ_READ (1<<3) |
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#define SVM_REQ_WRITE (1<<2) |
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#define SVM_REQ_EXEC (1<<1) |
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#define SVM_REQ_PRIV (1<<0) |
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/* |
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* The SVM_FLAG_PRIVATE_PASID flag requests a PASID which is *not* the "main" |
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* PASID for the current process. Even if a PASID already exists, a new one |
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* will be allocated. And the PASID allocated with SVM_FLAG_PRIVATE_PASID |
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* will not be given to subsequent callers. This facility allows a driver to |
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* disambiguate between multiple device contexts which access the same MM, |
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* if there is no other way to do so. It should be used sparingly, if at all. |
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*/ |
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#define SVM_FLAG_PRIVATE_PASID (1<<0) |
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/* |
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* The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only |
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* for access to kernel addresses. No IOTLB flushes are automatically done |
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* for kernel mappings; it is valid only for access to the kernel's static |
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* 1:1 mapping of physical memory — not to vmalloc or even module mappings. |
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* A future API addition may permit the use of such ranges, by means of an |
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* explicit IOTLB flush call (akin to the DMA API's unmap method). |
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* |
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* It is unlikely that we will ever hook into flush_tlb_kernel_range() to |
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* do such IOTLB flushes automatically. |
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*/ |
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#define SVM_FLAG_SUPERVISOR_MODE (1<<1) |
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#ifdef CONFIG_INTEL_IOMMU_SVM |
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/** |
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* intel_svm_bind_mm() - Bind the current process to a PASID |
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* @dev: Device to be granted acccess |
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* @pasid: Address for allocated PASID |
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* @flags: Flags. Later for requesting supervisor mode, etc. |
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* @ops: Callbacks to device driver |
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* |
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* This function attempts to enable PASID support for the given device. |
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* If the @pasid argument is non-%NULL, a PASID is allocated for access |
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* to the MM of the current process. |
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* |
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* By using a %NULL value for the @pasid argument, this function can |
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* be used to simply validate that PASID support is available for the |
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* given device — i.e. that it is behind an IOMMU which has the |
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* requisite support, and is enabled. |
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* |
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* Page faults are handled transparently by the IOMMU code, and there |
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* should be no need for the device driver to be involved. If a page |
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* fault cannot be handled (i.e. is an invalid address rather than |
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* just needs paging in), then the page request will be completed by |
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* the core IOMMU code with appropriate status, and the device itself |
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* can then report the resulting fault to its driver via whatever |
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* mechanism is appropriate. |
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* |
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* Multiple calls from the same process may result in the same PASID |
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* being re-used. A reference count is kept. |
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*/ |
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extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, |
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struct svm_dev_ops *ops); |
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/** |
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* intel_svm_unbind_mm() - Unbind a specified PASID |
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* @dev: Device for which PASID was allocated |
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* @pasid: PASID value to be unbound |
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* |
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* This function allows a PASID to be retired when the device no |
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* longer requires access to the address space of a given process. |
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* |
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* If the use count for the PASID in question reaches zero, the |
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* PASID is revoked and may no longer be used by hardware. |
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* |
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* Device drivers are required to ensure that no access (including |
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* page requests) is currently outstanding for the PASID in question, |
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* before calling this function. |
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*/ |
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extern int intel_svm_unbind_mm(struct device *dev, int pasid); |
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#else /* CONFIG_INTEL_IOMMU_SVM */ |
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static inline int intel_svm_bind_mm(struct device *dev, int *pasid, |
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int flags, struct svm_dev_ops *ops) |
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{ |
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return -ENOSYS; |
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} |
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static inline int intel_svm_unbind_mm(struct device *dev, int pasid) |
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{ |
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BUG(); |
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} |
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#endif /* CONFIG_INTEL_IOMMU_SVM */ |
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#define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) |
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#endif /* __INTEL_SVM_H__ */
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