On 17/05/2022 19:32, Niranjana Vishwanathapura wrote:
VM_BIND and related uapi definitions
v2: Ensure proper kernel-doc formatting with cross references.
Also add new uapi and documentation as per review comments
from Daniel.
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@xxxxxxxxx>
---
Documentation/gpu/rfc/i915_vm_bind.h | 399 +++++++++++++++++++++++++++
1 file changed, 399 insertions(+)
create mode 100644 Documentation/gpu/rfc/i915_vm_bind.h
diff --git a/Documentation/gpu/rfc/i915_vm_bind.h b/Documentation/gpu/rfc/i915_vm_bind.h
new file mode 100644
index 000000000000..589c0a009107
--- /dev/null
+++ b/Documentation/gpu/rfc/i915_vm_bind.h
@@ -0,0 +1,399 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2022 Intel Corporation
+ */
+
+/**
+ * DOC: I915_PARAM_HAS_VM_BIND
+ *
+ * VM_BIND feature availability.
+ * See typedef drm_i915_getparam_t param.
+ */
+#define I915_PARAM_HAS_VM_BIND 57
+
+/**
+ * DOC: I915_VM_CREATE_FLAGS_USE_VM_BIND
+ *
+ * Flag to opt-in for VM_BIND mode of binding during VM creation.
+ * See struct drm_i915_gem_vm_control flags.
+ *
+ * A VM in VM_BIND mode will not support the older execbuff mode of binding.
+ * In VM_BIND mode, execbuff ioctl will not accept any execlist (ie., the
+ * &drm_i915_gem_execbuffer2.buffer_count must be 0).
+ * Also, &drm_i915_gem_execbuffer2.batch_start_offset and
+ * &drm_i915_gem_execbuffer2.batch_len must be 0.
+ * DRM_I915_GEM_EXECBUFFER_EXT_BATCH_ADDRESSES extension must be provided
+ * to pass in the batch buffer addresses.
+ *
+ * Additionally, I915_EXEC_NO_RELOC, I915_EXEC_HANDLE_LUT and
+ * I915_EXEC_BATCH_FIRST of &drm_i915_gem_execbuffer2.flags must be 0
+ * (not used) in VM_BIND mode. I915_EXEC_USE_EXTENSIONS flag must always be
+ * set (See struct drm_i915_gem_execbuffer_ext_batch_addresses).
+ * The buffers_ptr, buffer_count, batch_start_offset and batch_len fields
+ * of struct drm_i915_gem_execbuffer2 are also not used and must be 0.
+ */
+#define I915_VM_CREATE_FLAGS_USE_VM_BIND (1 << 0)
+
+/**
+ * DOC: I915_CONTEXT_CREATE_FLAGS_LONG_RUNNING
+ *
+ * Flag to declare context as long running.
+ * See struct drm_i915_gem_context_create_ext flags.
+ *
+ * Usage of dma-fence expects that they complete in reasonable amount of time.
+ * Compute on the other hand can be long running. Hence it is not appropriate
+ * for compute contexts to export request completion dma-fence to user.
+ * The dma-fence usage will be limited to in-kernel consumption only.
+ * Compute contexts need to use user/memory fence.
+ *
+ * So, long running contexts do not support output fences. Hence,
+ * I915_EXEC_FENCE_OUT (See &drm_i915_gem_execbuffer2.flags and
+ * I915_EXEC_FENCE_SIGNAL (See &drm_i915_gem_exec_fence.flags) are expected
+ * to be not used.
+ *
+ * DRM_I915_GEM_WAIT ioctl call is also not supported for objects mapped
+ * to long running contexts.
+ */
+#define I915_CONTEXT_CREATE_FLAGS_LONG_RUNNING (1u << 2)
+
+/* VM_BIND related ioctls */
+#define DRM_I915_GEM_VM_BIND 0x3d
+#define DRM_I915_GEM_VM_UNBIND 0x3e
+#define DRM_I915_GEM_WAIT_USER_FENCE 0x3f
+
+#define DRM_IOCTL_I915_GEM_VM_BIND DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_BIND, struct drm_i915_gem_vm_bind)
+#define DRM_IOCTL_I915_GEM_VM_UNBIND DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_UNBIND, struct drm_i915_gem_vm_bind)
+#define DRM_IOCTL_I915_GEM_WAIT_USER_FENCE DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_WAIT_USER_FENCE, struct drm_i915_gem_wait_user_fence)
+
+/**
+ * struct drm_i915_gem_vm_bind - VA to object mapping to bind.
+ *
+ * This structure is passed to VM_BIND ioctl and specifies the mapping of GPU
+ * virtual address (VA) range to the section of an object that should be bound
+ * in the device page table of the specified address space (VM).
+ * The VA range specified must be unique (ie., not currently bound) and can
+ * be mapped to whole object or a section of the object (partial binding).
+ * Multiple VA mappings can be created to the same section of the object
+ * (aliasing).
+ */
+struct drm_i915_gem_vm_bind {
+ /** @vm_id: VM (address space) id to bind */
+ __u32 vm_id;
+
+ /** @handle: Object handle */
+ __u32 handle;
+
+ /** @start: Virtual Address start to bind */
+ __u64 start;
+
+ /** @offset: Offset in object to bind */
+ __u64 offset;
+
+ /** @length: Length of mapping to bind */
+ __u64 length;
Does it support, or should it, equivalent of EXEC_OBJECT_PAD_TO_SIZE? Or
if not userspace is expected to map the remainder of the space to a
dummy object? In which case would there be any alignment/padding issues
preventing the two bind to be placed next to each other?
I ask because someone from the compute side asked me about a problem
with their strategy of dealing with overfetch and I suggested pad to size.
Regards,
Tvrtko
+
+ /**
+ * @flags: Supported flags are,
+ *
+ * I915_GEM_VM_BIND_READONLY:
+ * Mapping is read-only.
+ *
+ * I915_GEM_VM_BIND_CAPTURE:
+ * Capture this mapping in the dump upon GPU error.
+ */
+ __u64 flags;
+#define I915_GEM_VM_BIND_READONLY (1 << 0)
+#define I915_GEM_VM_BIND_CAPTURE (1 << 1)
+
+ /** @extensions: 0-terminated chain of extensions for this mapping. */
+ __u64 extensions;
+};
+
+/**
+ * struct drm_i915_gem_vm_unbind - VA to object mapping to unbind.
+ *
+ * This structure is passed to VM_UNBIND ioctl and specifies the GPU virtual
+ * address (VA) range that should be unbound from the device page table of the
+ * specified address space (VM). The specified VA range must match one of the
+ * mappings created with the VM_BIND ioctl. TLB is flushed upon unbind
+ * completion.
+ */
+struct drm_i915_gem_vm_unbind {
+ /** @vm_id: VM (address space) id to bind */
+ __u32 vm_id;
+
+ /** @rsvd: Reserved for future use; must be zero. */
+ __u32 rsvd;
+
+ /** @start: Virtual Address start to unbind */
+ __u64 start;
+
+ /** @length: Length of mapping to unbind */
+ __u64 length;
+
+ /** @flags: reserved for future usage, currently MBZ */
+ __u64 flags;
+
+ /** @extensions: 0-terminated chain of extensions for this mapping. */
+ __u64 extensions;
+};
+
+/**
+ * struct drm_i915_vm_bind_fence - An input or output fence for the vm_bind
+ * or the vm_unbind work.
+ *
+ * The vm_bind or vm_unbind aync worker will wait for input fence to signal
+ * before starting the binding or unbinding.
+ *
+ * The vm_bind or vm_unbind async worker will signal the returned output fence
+ * after the completion of binding or unbinding.
+ */
+struct drm_i915_vm_bind_fence {
+ /** @handle: User's handle for a drm_syncobj to wait on or signal. */
+ __u32 handle;
+
+ /**
+ * @flags: Supported flags are,
+ *
+ * I915_VM_BIND_FENCE_WAIT:
+ * Wait for the input fence before binding/unbinding
+ *
+ * I915_VM_BIND_FENCE_SIGNAL:
+ * Return bind/unbind completion fence as output
+ */
+ __u32 flags;
+#define I915_VM_BIND_FENCE_WAIT (1<<0)
+#define I915_VM_BIND_FENCE_SIGNAL (1<<1)
+#define __I915_VM_BIND_FENCE_UNKNOWN_FLAGS (-(I915_VM_BIND_FENCE_SIGNAL << 1))
+};
+
+/**
+ * struct drm_i915_vm_bind_ext_timeline_fences - Timeline fences for vm_bind
+ * and vm_unbind.
+ *
+ * This structure describes an array of timeline drm_syncobj and associated
+ * points for timeline variants of drm_syncobj. These timeline 'drm_syncobj's
+ * can be input or output fences (See struct drm_i915_vm_bind_fence).
+ */
+struct drm_i915_vm_bind_ext_timeline_fences {
+#define I915_VM_BIND_EXT_timeline_FENCES 0
+ /** @base: Extension link. See struct i915_user_extension. */
+ struct i915_user_extension base;
+
+ /**
+ * @fence_count: Number of elements in the @handles_ptr & @value_ptr
+ * arrays.
+ */
+ __u64 fence_count;
+
+ /**
+ * @handles_ptr: Pointer to an array of struct drm_i915_vm_bind_fence
+ * of length @fence_count.
+ */
+ __u64 handles_ptr;
+
+ /**
+ * @values_ptr: Pointer to an array of u64 values of length
+ * @fence_count.
+ * Values must be 0 for a binary drm_syncobj. A Value of 0 for a
+ * timeline drm_syncobj is invalid as it turns a drm_syncobj into a
+ * binary one.
+ */
+ __u64 values_ptr;
+};
+
+/**
+ * struct drm_i915_vm_bind_user_fence - An input or output user fence for the
+ * vm_bind or the vm_unbind work.
+ *
+ * The vm_bind or vm_unbind aync worker will wait for the input fence (value at
+ * @addr to become equal to @val) before starting the binding or unbinding.
+ *
+ * The vm_bind or vm_unbind async worker will signal the output fence after
+ * the completion of binding or unbinding by writing @val to memory location at
+ * @addr
+ */
+struct drm_i915_vm_bind_user_fence {
+ /** @addr: User/Memory fence qword aligned process virtual address */
+ __u64 addr;
+
+ /** @val: User/Memory fence value to be written after bind completion */
+ __u64 val;
+
+ /**
+ * @flags: Supported flags are,
+ *
+ * I915_VM_BIND_USER_FENCE_WAIT:
+ * Wait for the input fence before binding/unbinding
+ *
+ * I915_VM_BIND_USER_FENCE_SIGNAL:
+ * Return bind/unbind completion fence as output
+ */
+ __u32 flags;
+#define I915_VM_BIND_USER_FENCE_WAIT (1<<0)
+#define I915_VM_BIND_USER_FENCE_SIGNAL (1<<1)
+#define __I915_VM_BIND_USER_FENCE_UNKNOWN_FLAGS \
+ (-(I915_VM_BIND_USER_FENCE_SIGNAL << 1))
+};
+
+/**
+ * struct drm_i915_vm_bind_ext_user_fence - User/memory fences for vm_bind
+ * and vm_unbind.
+ *
+ * These user fences can be input or output fences
+ * (See struct drm_i915_vm_bind_user_fence).
+ */
+struct drm_i915_vm_bind_ext_user_fence {
+#define I915_VM_BIND_EXT_USER_FENCES 1
+ /** @base: Extension link. See struct i915_user_extension. */
+ struct i915_user_extension base;
+
+ /** @fence_count: Number of elements in the @user_fence_ptr array. */
+ __u64 fence_count;
+
+ /**
+ * @user_fence_ptr: Pointer to an array of
+ * struct drm_i915_vm_bind_user_fence of length @fence_count.
+ */
+ __u64 user_fence_ptr;
+};
+
+/**
+ * struct drm_i915_gem_execbuffer_ext_batch_addresses - Array of batch buffer
+ * gpu virtual addresses.
+ *
+ * In the execbuff ioctl (See struct drm_i915_gem_execbuffer2), this extension
+ * must always be appended in the VM_BIND mode and it will be an error to
+ * append this extension in older non-VM_BIND mode.
+ */
+struct drm_i915_gem_execbuffer_ext_batch_addresses {
+#define DRM_I915_GEM_EXECBUFFER_EXT_BATCH_ADDRESSES 1
+ /** @base: Extension link. See struct i915_user_extension. */
+ struct i915_user_extension base;
+
+ /** @count: Number of addresses in the addr array. */
+ __u32 count;
+
+ /** @addr: An array of batch gpu virtual addresses. */
+ __u64 addr[0];
+};
+
+/**
+ * struct drm_i915_gem_execbuffer_ext_user_fence - First level batch completion
+ * signaling extension.
+ *
+ * This extension allows user to attach a user fence (@addr, @value pair) to an
+ * execbuf to be signaled by the command streamer after the completion of first
+ * level batch, by writing the @value at specified @addr and triggering an
+ * interrupt.
+ * User can either poll for this user fence to signal or can also wait on it
+ * with i915_gem_wait_user_fence ioctl.
+ * This is very much usefaul for long running contexts where waiting on dma-fence
+ * by user (like i915_gem_wait ioctl) is not supported.
+ */
+struct drm_i915_gem_execbuffer_ext_user_fence {
+#define DRM_I915_GEM_EXECBUFFER_EXT_USER_FENCE 2
+ /** @base: Extension link. See struct i915_user_extension. */
+ struct i915_user_extension base;
+
+ /**
+ * @addr: User/Memory fence qword aligned GPU virtual address.
+ *
+ * Address has to be a valid GPU virtual address at the time of
+ * first level batch completion.
+ */
+ __u64 addr;
+
+ /**
+ * @value: User/Memory fence Value to be written to above address
+ * after first level batch completes.
+ */
+ __u64 value;
+
+ /** @rsvd: Reserved for future extensions, MBZ */
+ __u64 rsvd;
+};
+
+/**
+ * struct drm_i915_gem_create_ext_vm_private - Extension to make the object
+ * private to the specified VM.
+ *
+ * See struct drm_i915_gem_create_ext.
+ */
+struct drm_i915_gem_create_ext_vm_private {
+#define I915_GEM_CREATE_EXT_VM_PRIVATE 2
+ /** @base: Extension link. See struct i915_user_extension. */
+ struct i915_user_extension base;
+
+ /** @vm_id: Id of the VM to which the object is private */
+ __u32 vm_id;
+};
+
+/**
+ * struct drm_i915_gem_wait_user_fence - Wait on user/memory fence.
+ *
+ * User/Memory fence can be woken up either by:
+ *
+ * 1. GPU context indicated by @ctx_id, or,
+ * 2. Kerrnel driver async worker upon I915_UFENCE_WAIT_SOFT.
+ * @ctx_id is ignored when this flag is set.
+ *
+ * Wakeup condition is,
+ * ``((*addr & mask) op (value & mask))``
+ *
+ * See :ref:`Documentation/driver-api/dma-buf.rst <indefinite_dma_fences>`
+ */
+struct drm_i915_gem_wait_user_fence {
+ /** @extensions: Zero-terminated chain of extensions. */
+ __u64 extensions;
+
+ /** @addr: User/Memory fence address */
+ __u64 addr;
+
+ /** @ctx_id: Id of the Context which will signal the fence. */
+ __u32 ctx_id;
+
+ /** @op: Wakeup condition operator */
+ __u16 op;
+#define I915_UFENCE_WAIT_EQ 0
+#define I915_UFENCE_WAIT_NEQ 1
+#define I915_UFENCE_WAIT_GT 2
+#define I915_UFENCE_WAIT_GTE 3
+#define I915_UFENCE_WAIT_LT 4
+#define I915_UFENCE_WAIT_LTE 5
+#define I915_UFENCE_WAIT_BEFORE 6
+#define I915_UFENCE_WAIT_AFTER 7
+
+ /**
+ * @flags: Supported flags are,
+ *
+ * I915_UFENCE_WAIT_SOFT:
+ *
+ * To be woken up by i915 driver async worker (not by GPU).
+ *
+ * I915_UFENCE_WAIT_ABSTIME:
+ *
+ * Wait timeout specified as absolute time.
+ */
+ __u16 flags;
+#define I915_UFENCE_WAIT_SOFT 0x1
+#define I915_UFENCE_WAIT_ABSTIME 0x2
+
+ /** @value: Wakeup value */
+ __u64 value;
+
+ /** @mask: Wakeup mask */
+ __u64 mask;
+#define I915_UFENCE_WAIT_U8 0xffu
+#define I915_UFENCE_WAIT_U16 0xffffu
+#define I915_UFENCE_WAIT_U32 0xfffffffful
+#define I915_UFENCE_WAIT_U64 0xffffffffffffffffull
+
+ /**
+ * @timeout: Wait timeout in nanoseconds.
+ *
+ * If I915_UFENCE_WAIT_ABSTIME flag is set, then time timeout is the
+ * absolute time in nsec.
+ */
+ __s64 timeout;
+};
