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Diffstat (limited to 'include/linux/intel-svm.h')
| -rw-r--r-- | include/linux/intel-svm.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h new file mode 100644 index 000000000..3c2579404 --- /dev/null +++ b/include/linux/intel-svm.h @@ -0,0 +1,121 @@ +/* + * Copyright © 2015 Intel Corporation. + * + * Authors: David Woodhouse <David.Woodhouse@intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#ifndef __INTEL_SVM_H__ +#define __INTEL_SVM_H__ + +struct device; + +struct svm_dev_ops { + void (*fault_cb)(struct device *dev, int pasid, u64 address, + u32 private, int rwxp, int response); +}; + +/* Values for rxwp in fault_cb callback */ +#define SVM_REQ_READ (1<<3) +#define SVM_REQ_WRITE (1<<2) +#define SVM_REQ_EXEC (1<<1) +#define SVM_REQ_PRIV (1<<0) + + +/* + * The SVM_FLAG_PRIVATE_PASID flag requests a PASID which is *not* the "main" + * PASID for the current process. Even if a PASID already exists, a new one + * will be allocated. And the PASID allocated with SVM_FLAG_PRIVATE_PASID + * will not be given to subsequent callers. This facility allows a driver to + * disambiguate between multiple device contexts which access the same MM, + * if there is no other way to do so. It should be used sparingly, if at all. + */ +#define SVM_FLAG_PRIVATE_PASID (1<<0) + +/* + * The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only + * for access to kernel addresses. No IOTLB flushes are automatically done + * for kernel mappings; it is valid only for access to the kernel's static + * 1:1 mapping of physical memory — not to vmalloc or even module mappings. + * A future API addition may permit the use of such ranges, by means of an + * explicit IOTLB flush call (akin to the DMA API's unmap method). + * + * It is unlikely that we will ever hook into flush_tlb_kernel_range() to + * do such IOTLB flushes automatically. + */ +#define SVM_FLAG_SUPERVISOR_MODE (1<<1) + +#ifdef CONFIG_INTEL_IOMMU_SVM + +/** + * intel_svm_bind_mm() - Bind the current process to a PASID + * @dev: Device to be granted acccess + * @pasid: Address for allocated PASID + * @flags: Flags. Later for requesting supervisor mode, etc. + * @ops: Callbacks to device driver + * + * This function attempts to enable PASID support for the given device. + * If the @pasid argument is non-%NULL, a PASID is allocated for access + * to the MM of the current process. + * + * By using a %NULL value for the @pasid argument, this function can + * be used to simply validate that PASID support is available for the + * given device — i.e. that it is behind an IOMMU which has the + * requisite support, and is enabled. + * + * Page faults are handled transparently by the IOMMU code, and there + * should be no need for the device driver to be involved. If a page + * fault cannot be handled (i.e. is an invalid address rather than + * just needs paging in), then the page request will be completed by + * the core IOMMU code with appropriate status, and the device itself + * can then report the resulting fault to its driver via whatever + * mechanism is appropriate. + * + * Multiple calls from the same process may result in the same PASID + * being re-used. A reference count is kept. + */ +extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, + struct svm_dev_ops *ops); + +/** + * intel_svm_unbind_mm() - Unbind a specified PASID + * @dev: Device for which PASID was allocated + * @pasid: PASID value to be unbound + * + * This function allows a PASID to be retired when the device no + * longer requires access to the address space of a given process. + * + * If the use count for the PASID in question reaches zero, the + * PASID is revoked and may no longer be used by hardware. + * + * Device drivers are required to ensure that no access (including + * page requests) is currently outstanding for the PASID in question, + * before calling this function. + */ +extern int intel_svm_unbind_mm(struct device *dev, int pasid); + +#else /* CONFIG_INTEL_IOMMU_SVM */ + +static inline int intel_svm_bind_mm(struct device *dev, int *pasid, + int flags, struct svm_dev_ops *ops) +{ + return -ENOSYS; +} + +static inline int intel_svm_unbind_mm(struct device *dev, int pasid) +{ + BUG(); +} +#endif /* CONFIG_INTEL_IOMMU_SVM */ + +#define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) + +#endif /* __INTEL_SVM_H__ */ |