--- /dev/null
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include "xe_pagefault.h"
+#include "xe_pagefault_types.h"
+
+/**
+ * DOC: Xe page faults
+ *
+ * Xe page faults are handled in two layers. The producer layer interacts with
+ * hardware or firmware to receive and parse faults into struct xe_pagefault,
+ * then forwards them to the consumer. The consumer layer services the faults
+ * (e.g., memory migration, page table updates) and acknowledges the result back
+ * to the producer, which then forwards the results to the hardware or firmware.
+ * The consumer uses a page fault queue sized to absorb all potential faults and
+ * a multi-threaded worker to process them. Multiple producers are supported,
+ * with a single shared consumer.
+ *
+ * xe_pagefault.c implements the consumer layer.
+ */
+
+/**
+ * xe_pagefault_init() - Page fault init
+ * @xe: xe device instance
+ *
+ * Initialize Xe page fault state. Must be done after reading fuses.
+ *
+ * Return: 0 on Success, errno on failure
+ */
+int xe_pagefault_init(struct xe_device *xe)
+{
+ /* TODO - implement */
+ return 0;
+}
+
+/**
+ * xe_pagefault_reset() - Page fault reset for a GT
+ * @xe: xe device instance
+ * @gt: GT being reset
+ *
+ * Reset the Xe page fault state for a GT; that is, squash any pending faults on
+ * the GT.
+ */
+void xe_pagefault_reset(struct xe_device *xe, struct xe_gt *gt)
+{
+ /* TODO - implement */
+}
+
+/**
+ * xe_pagefault_handler() - Page fault handler
+ * @xe: xe device instance
+ * @pf: Page fault
+ *
+ * Sink the page fault to a queue (i.e., a memory buffer) and queue a worker to
+ * service it. Safe to be called from IRQ or process context. Reclaim safe.
+ *
+ * Return: 0 on success, errno on failure
+ */
+int xe_pagefault_handler(struct xe_device *xe, struct xe_pagefault *pf)
+{
+ /* TODO - implement */
+ return 0;
+}
--- /dev/null
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef _XE_PAGEFAULT_TYPES_H_
+#define _XE_PAGEFAULT_TYPES_H_
+
+#include <linux/workqueue.h>
+
+struct xe_gt;
+struct xe_pagefault;
+
+/** enum xe_pagefault_access_type - Xe page fault access type */
+enum xe_pagefault_access_type {
+ /** @XE_PAGEFAULT_ACCESS_TYPE_READ: Read access type */
+ XE_PAGEFAULT_ACCESS_TYPE_READ = 0,
+ /** @XE_PAGEFAULT_ACCESS_TYPE_WRITE: Write access type */
+ XE_PAGEFAULT_ACCESS_TYPE_WRITE = 1,
+ /** @XE_PAGEFAULT_ACCESS_TYPE_ATOMIC: Atomic access type */
+ XE_PAGEFAULT_ACCESS_TYPE_ATOMIC = 2,
+};
+
+/** enum xe_pagefault_type - Xe page fault type */
+enum xe_pagefault_type {
+ /** @XE_PAGEFAULT_TYPE_NOT_PRESENT: Not present */
+ XE_PAGEFAULT_TYPE_NOT_PRESENT = 0,
+ /** @XE_PAGEFAULT_TYPE_WRITE_ACCESS_VIOLATION: Write access violation */
+ XE_PAGEFAULT_TYPE_WRITE_ACCESS_VIOLATION = 1,
+ /** @XE_PAGEFAULT_TYPE_ATOMIC_ACCESS_VIOLATION: Atomic access violation */
+ XE_PAGEFAULT_TYPE_ATOMIC_ACCESS_VIOLATION = 2,
+};
+
+/** struct xe_pagefault_ops - Xe pagefault ops (producer) */
+struct xe_pagefault_ops {
+ /**
+ * @ack_fault: Ack fault
+ * @pf: Page fault
+ * @err: Error state of fault
+ *
+ * Page fault producer receives acknowledgment from the consumer and
+ * sends the result to the HW/FW interface.
+ */
+ void (*ack_fault)(struct xe_pagefault *pf, int err);
+};
+
+/**
+ * struct xe_pagefault - Xe page fault
+ *
+ * Generic page fault structure for communication between producer and consumer.
+ * Carefully sized to be 64 bytes. Upon a device page fault, the producer
+ * populates this structure, and the consumer copies it into the page-fault
+ * queue for deferred handling.
+ */
+struct xe_pagefault {
+ /**
+ * @gt: GT of fault
+ */
+ struct xe_gt *gt;
+ /**
+ * @consumer: State for the software handling the fault. Populated by
+ * the producer and may be modified by the consumer to communicate
+ * information back to the producer upon fault acknowledgment.
+ */
+ struct {
+ /** @consumer.page_addr: address of page fault */
+ u64 page_addr;
+ /** @consumer.asid: address space ID */
+ u32 asid;
+ /**
+ * @consumer.access_type: access type, u8 rather than enum to
+ * keep size compact
+ */
+ u8 access_type;
+ /**
+ * @consumer.fault_type: fault type, u8 rather than enum to
+ * keep size compact
+ */
+ u8 fault_type;
+#define XE_PAGEFAULT_LEVEL_NACK 0xff /* Producer indicates nack fault */
+ /** @consumer.fault_level: fault level */
+ u8 fault_level;
+ /** @consumer.engine_class: engine class */
+ u8 engine_class;
+ /** @consumer.engine_instance: engine instance */
+ u8 engine_instance;
+ /** consumer.reserved: reserved bits for future expansion */
+ u8 reserved[7];
+ } consumer;
+ /**
+ * @producer: State for the producer (i.e., HW/FW interface). Populated
+ * by the producer and should not be modified—or even inspected—by the
+ * consumer, except for calling operations.
+ */
+ struct {
+ /** @producer.private: private pointer */
+ void *private;
+ /** @producer.ops: operations */
+ const struct xe_pagefault_ops *ops;
+#define XE_PAGEFAULT_PRODUCER_MSG_LEN_DW 4
+ /**
+ * @producer.msg: page fault message, used by producer in fault
+ * acknowledgment to formulate response to HW/FW interface.
+ * Included in the page-fault message because the producer
+ * typically receives the fault in a context where memory cannot
+ * be allocated (e.g., atomic context or the reclaim path).
+ */
+ u32 msg[XE_PAGEFAULT_PRODUCER_MSG_LEN_DW];
+ } producer;
+};
+
+/**
+ * struct xe_pagefault_queue: Xe pagefault queue (consumer)
+ *
+ * Used to capture all device page faults for deferred processing. Size this
+ * queue to absorb the device’s worst-case number of outstanding faults.
+ */
+struct xe_pagefault_queue {
+ /**
+ * @data: Data in queue containing struct xe_pagefault, protected by
+ * @lock
+ */
+ void *data;
+ /** @size: Size of queue in bytes */
+ u32 size;
+ /** @head: Head pointer in bytes, moved by producer, protected by @lock */
+ u32 head;
+ /** @tail: Tail pointer in bytes, moved by consumer, protected by @lock */
+ u32 tail;
+ /** @lock: protects page fault queue */
+ spinlock_t lock;
+ /** @worker: to process page faults */
+ struct work_struct worker;
+};
+
+#endif
projects / thirdparty / kernel / linux.git / commitdiff
