drm/amdkfd: CRIU Introduce Checkpoint-Restore APIs

Checkpoint-Restore in userspace (CRIU) is a powerful tool that can
snapshot a running process and later restore it on same or a remote
machine but expects the processes that have a device file (e.g. GPU)
associated with them, provide necessary driver support to assist CRIU
and its extensible plugin interface. Thus, In order to support the
Checkpoint-Restore of any ROCm process, the AMD Radeon Open Compute
Kernel driver, needs to provide a set of new APIs that provide
necessary VRAM metadata and its contents to a userspace component
(CRIU plugin) that can store it in form of image files.

This introduces some new ioctls which will be used to checkpoint-Restore
any KFD bound user process. KFD only allows ioctl calls from the same
process that opened the KFD file descriptor. Since these ioctls are
expected to be called from a KFD criu plugin which has elevated ptrace
attached privileges and CAP_CHECKPOINT_RESTORE capabilities attached with
the file descriptors so modify KFD to allow such calls.

(API redesigned by David Yat Sin)
Suggested-by: Felix Kuehling <felix.kuehling@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: David Yat Sin <david.yatsin@amd.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 80 insertions, 1 deletions

diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
index af96af174dc4..49429a6c42fc 100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -468,6 +468,82 @@ struct kfd_ioctl_smi_events_args {
 	__u32 anon_fd;	/* from KFD */
 };
 
+/**************************************************************************************************
+ * CRIU IOCTLs (Checkpoint Restore In Userspace)
+ *
+ * When checkpointing a process, the userspace application will perform:
+ * 1. PROCESS_INFO op to determine current process information. This pauses execution and evicts
+ *    all the queues.
+ * 2. CHECKPOINT op to checkpoint process contents (BOs, queues, events, svm-ranges)
+ * 3. UNPAUSE op to un-evict all the queues
+ *
+ * When restoring a process, the CRIU userspace application will perform:
+ *
+ * 1. RESTORE op to restore process contents
+ * 2. RESUME op to start the process
+ *
+ * Note: Queues are forced into an evicted state after a successful PROCESS_INFO. User
+ * application needs to perform an UNPAUSE operation after calling PROCESS_INFO.
+ */
+
+enum kfd_criu_op {
+	KFD_CRIU_OP_PROCESS_INFO,
+	KFD_CRIU_OP_CHECKPOINT,
+	KFD_CRIU_OP_UNPAUSE,
+	KFD_CRIU_OP_RESTORE,
+	KFD_CRIU_OP_RESUME,
+};
+
+/**
+ * kfd_ioctl_criu_args - Arguments perform CRIU operation
+ * @devices:		[in/out] User pointer to memory location for devices information.
+ * 			This is an array of type kfd_criu_device_bucket.
+ * @bos:		[in/out] User pointer to memory location for BOs information
+ * 			This is an array of type kfd_criu_bo_bucket.
+ * @priv_data:		[in/out] User pointer to memory location for private data
+ * @priv_data_size:	[in/out] Size of priv_data in bytes
+ * @num_devices:	[in/out] Number of GPUs used by process. Size of @devices array.
+ * @num_bos		[in/out] Number of BOs used by process. Size of @bos array.
+ * @num_objects:	[in/out] Number of objects used by process. Objects are opaque to
+ *				 user application.
+ * @pid:		[in/out] PID of the process being checkpointed
+ * @op			[in] Type of operation (kfd_criu_op)
+ *
+ * Return: 0 on success, -errno on failure
+ */
+struct kfd_ioctl_criu_args {
+	__u64 devices;		/* Used during ops: CHECKPOINT, RESTORE */
+	__u64 bos;		/* Used during ops: CHECKPOINT, RESTORE */
+	__u64 priv_data;	/* Used during ops: CHECKPOINT, RESTORE */
+	__u64 priv_data_size;	/* Used during ops: PROCESS_INFO, RESTORE */
+	__u32 num_devices;	/* Used during ops: PROCESS_INFO, RESTORE */
+	__u32 num_bos;		/* Used during ops: PROCESS_INFO, RESTORE */
+	__u32 num_objects;	/* Used during ops: PROCESS_INFO, RESTORE */
+	__u32 pid;		/* Used during ops: PROCESS_INFO, RESUME */
+	__u32 op;
+};
+
+struct kfd_criu_device_bucket {
+	__u32 user_gpu_id;
+	__u32 actual_gpu_id;
+	__u32 drm_fd;
+	__u32 pad;
+};
+
+struct kfd_criu_bo_bucket {
+	__u64 addr;
+	__u64 size;
+	__u64 offset;
+	__u64 restored_offset;    /* During restore, updated offset for BO */
+	__u32 gpu_id;             /* This is the user_gpu_id */
+	__u32 alloc_flags;
+	__u32 dmabuf_fd;
+	__u32 pad;
+};
+
+/* CRIU IOCTLs - END */
+/**************************************************************************************************/
+
 /* Register offset inside the remapped mmio page
  */
 enum kfd_mmio_remap {
@@ -742,7 +818,10 @@ struct kfd_ioctl_set_xnack_mode_args {
 #define AMDKFD_IOC_SET_XNACK_MODE		\
 		AMDKFD_IOWR(0x21, struct kfd_ioctl_set_xnack_mode_args)
 
+#define AMDKFD_IOC_CRIU_OP			\
+		AMDKFD_IOWR(0x22, struct kfd_ioctl_criu_args)
+
 #define AMDKFD_COMMAND_START		0x01
-#define AMDKFD_COMMAND_END		0x22
+#define AMDKFD_COMMAND_END		0x23
 
 #endif