[PATCH 04/35] drm/amdkfd: add svm ioctl API

[Felix Kuehling <Felix.Kuehling@amd.com>]

From: Philip Yang <Philip.Yang@amd.com>

Add svm (shared virtual memory) ioctl data structure and API definition.

The svm ioctl API is designed to be extensible in the future. All
operations are provided by a single IOCTL to preserve ioctl number
space. The arguments structure ends with a variable size array of
attributes that can be used to set or get one or multiple attributes.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c |   7 ++
 include/uapi/linux/kfd_ioctl.h           | 128 ++++++++++++++++++++++-
 2 files changed, 133 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 8c87afce12df..c5288a6e45b9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -1746,6 +1746,11 @@ static int kfd_ioctl_smi_events(struct file *filep,
 	return kfd_smi_event_open(dev, &args->anon_fd);
 }
 
+static int kfd_ioctl_svm(struct file *filep, struct kfd_process *p, void *data)
+{
+	return -EINVAL;
+}
+
 #define AMDKFD_IOCTL_DEF(ioctl, _func, _flags) \
 	[_IOC_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags, \
 			    .cmd_drv = 0, .name = #ioctl}
@@ -1844,6 +1849,8 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
 
 	AMDKFD_IOCTL_DEF(AMDKFD_IOC_SMI_EVENTS,
 			kfd_ioctl_smi_events, 0),
+
+	AMDKFD_IOCTL_DEF(AMDKFD_IOC_SVM, kfd_ioctl_svm, 0),
 };
 
 #define AMDKFD_CORE_IOCTL_COUNT	ARRAY_SIZE(amdkfd_ioctls)
diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
index 695b606da4b1..5d4a4b3e0b61 100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -29,9 +29,10 @@
 /*
  * - 1.1 - initial version
  * - 1.3 - Add SMI events support
+ * - 1.4 - Add SVM API
  */
 #define KFD_IOCTL_MAJOR_VERSION 1
-#define KFD_IOCTL_MINOR_VERSION 3
+#define KFD_IOCTL_MINOR_VERSION 4
 
 struct kfd_ioctl_get_version_args {
 	__u32 major_version;	/* from KFD */
@@ -471,6 +472,127 @@ enum kfd_mmio_remap {
 	KFD_MMIO_REMAP_HDP_REG_FLUSH_CNTL = 4,
 };
 
+/* Guarantee host access to memory */
+#define KFD_IOCTL_SVM_FLAG_HOST_ACCESS 0x00000001
+/* Fine grained coherency between all devices with access */
+#define KFD_IOCTL_SVM_FLAG_COHERENT    0x00000002
+/* Use any GPU in same hive as preferred device */
+#define KFD_IOCTL_SVM_FLAG_HIVE_LOCAL  0x00000004
+/* GPUs only read, allows replication */
+#define KFD_IOCTL_SVM_FLAG_GPU_RO      0x00000008
+/* Allow execution on GPU */
+#define KFD_IOCTL_SVM_FLAG_GPU_EXEC    0x00000010
+
+/**
+ * kfd_ioctl_svm_op - SVM ioctl operations
+ *
+ * @KFD_IOCTL_SVM_OP_SET_ATTR: Modify one or more attributes
+ * @KFD_IOCTL_SVM_OP_GET_ATTR: Query one or more attributes
+ */
+enum kfd_ioctl_svm_op {
+	KFD_IOCTL_SVM_OP_SET_ATTR,
+	KFD_IOCTL_SVM_OP_GET_ATTR
+};
+
+/** kfd_ioctl_svm_location - Enum for preferred and prefetch locations
+ *
+ * GPU IDs are used to specify GPUs as preferred and prefetch locations.
+ * Below definitions are used for system memory or for leaving the preferred
+ * location unspecified.
+ */
+enum kfd_ioctl_svm_location {
+	KFD_IOCTL_SVM_LOCATION_SYSMEM = 0,
+	KFD_IOCTL_SVM_LOCATION_UNDEFINED = 0xffffffff
+};
+
+/**
+ * kfd_ioctl_svm_attr_type - SVM attribute types
+ *
+ * @KFD_IOCTL_SVM_ATTR_PREFERRED_LOC: gpuid of the preferred location, 0 for
+ *                                    system memory
+ * @KFD_IOCTL_SVM_ATTR_PREFETCH_LOC: gpuid of the prefetch location, 0 for
+ *                                   system memory. Setting this triggers an
+ *                                   immediate prefetch (migration).
+ * @KFD_IOCTL_SVM_ATTR_ACCESS:
+ * @KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
+ * @KFD_IOCTL_SVM_ATTR_NO_ACCESS: specify memory access for the gpuid given
+ *                                by the attribute value
+ * @KFD_IOCTL_SVM_ATTR_SET_FLAGS: bitmask of flags to set (see
+ *                                KFD_IOCTL_SVM_FLAG_...)
+ * @KFD_IOCTL_SVM_ATTR_CLR_FLAGS: bitmask of flags to clear
+ * @KFD_IOCTL_SVM_ATTR_GRANULARITY: migration granularity
+ *                                  (log2 num pages)
+ */
+enum kfd_ioctl_svm_attr_type {
+	KFD_IOCTL_SVM_ATTR_PREFERRED_LOC,
+	KFD_IOCTL_SVM_ATTR_PREFETCH_LOC,
+	KFD_IOCTL_SVM_ATTR_ACCESS,
+	KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE,
+	KFD_IOCTL_SVM_ATTR_NO_ACCESS,
+	KFD_IOCTL_SVM_ATTR_SET_FLAGS,
+	KFD_IOCTL_SVM_ATTR_CLR_FLAGS,
+	KFD_IOCTL_SVM_ATTR_GRANULARITY
+};
+
+/**
+ * kfd_ioctl_svm_attribute - Attributes as pairs of type and value
+ *
+ * The meaning of the @value depends on the attribute type.
+ *
+ * @type: attribute type (see enum @kfd_ioctl_svm_attr_type)
+ * @value: attribute value
+ */
+struct kfd_ioctl_svm_attribute {
+	__u32 type;
+	__u32 value;
+};
+
+/**
+ * kfd_ioctl_svm_args - Arguments for SVM ioctl
+ *
+ * @op specifies the operation to perform (see enum
+ * @kfd_ioctl_svm_op).  @start_addr and @size are common for all
+ * operations.
+ *
+ * A variable number of attributes can be given in @attrs.
+ * @nattr specifies the number of attributes. New attributes can be
+ * added in the future without breaking the ABI. If unknown attributes
+ * are given, the function returns -EINVAL.
+ *
+ * @KFD_IOCTL_SVM_OP_SET_ATTR sets attributes for a virtual address
+ * range. It may overlap existing virtual address ranges. If it does,
+ * the existing ranges will be split such that the attribute changes
+ * only apply to the specified address range.
+ *
+ * @KFD_IOCTL_SVM_OP_GET_ATTR returns the intersection of attributes
+ * over all memory in the given range and returns the result as the
+ * attribute value. If different pages have different preferred or
+ * prefetch locations, 0xffffffff will be returned for
+ * @KFD_IOCTL_SVM_ATTR_PREFERRED_LOC or
+ * @KFD_IOCTL_SVM_ATTR_PREFETCH_LOC resepctively. For
+ * @KFD_IOCTL_SVM_ATTR_SET_FLAGS, flags of all pages will be
+ * aggregated by bitwise AND. The minimum  migration granularity
+ * throughout the range will be returned for
+ * @KFD_IOCTL_SVM_ATTR_GRANULARITY.
+ *
+ * Querying of accessibility attributes works by initializing the
+ * attribute type to @KFD_IOCTL_SVM_ATTR_ACCESS and the value to the
+ * GPUID being queried. Multiple attributes can be given to allow
+ * querying multiple GPUIDs. The ioctl function overwrites the
+ * attribute type to indicate the access for the specified GPU.
+ *
+ * @KFD_IOCTL_SVM_ATTR_CLR_FLAGS is invalid for
+ * @KFD_IOCTL_SVM_OP_GET_ATTR.
+ */
+struct kfd_ioctl_svm_args {
+	__u64 start_addr;
+	__u64 size;
+	__u32 op;
+	__u32 nattr;
+	/* Variable length array of attributes */
+	struct kfd_ioctl_svm_attribute attrs[0];
+};
+
 #define AMDKFD_IOCTL_BASE 'K'
 #define AMDKFD_IO(nr)			_IO(AMDKFD_IOCTL_BASE, nr)
 #define AMDKFD_IOR(nr, type)		_IOR(AMDKFD_IOCTL_BASE, nr, type)
@@ -571,7 +693,9 @@ enum kfd_mmio_remap {
 #define AMDKFD_IOC_SMI_EVENTS			\
 		AMDKFD_IOWR(0x1F, struct kfd_ioctl_smi_events_args)
 
+#define AMDKFD_IOC_SVM	AMDKFD_IOWR(0x20, struct kfd_ioctl_svm_args)
+
 #define AMDKFD_COMMAND_START		0x01
-#define AMDKFD_COMMAND_END		0x20
+#define AMDKFD_COMMAND_END		0x21
 
 #endif
-- 
2.29.2

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