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 000000000000..3c25794042f9
--- /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__ */