[PATCH v2 08/20] util/dsa: Implement DSA task enqueue and dequeue.

[Hao Xiang]

* Use a safe thread queue for DSA task enqueue/dequeue.
* Implement DSA task submission.
* Implement DSA batch task submission.

Signed-off-by: Hao Xiang <hao.xiang@bytedance.com>
---
 include/qemu/dsa.h |  35 ++++++++
 util/dsa.c         | 196 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 231 insertions(+)

diff --git a/include/qemu/dsa.h b/include/qemu/dsa.h
index 30246b507e..23f55185be 100644
--- a/include/qemu/dsa.h
+++ b/include/qemu/dsa.h
@@ -12,6 +12,41 @@
 #include <linux/idxd.h>
 #include "x86intrin.h"
 
+enum dsa_task_type {
+    DSA_TASK = 0,
+    DSA_BATCH_TASK
+};
+
+enum dsa_task_status {
+    DSA_TASK_READY = 0,
+    DSA_TASK_PROCESSING,
+    DSA_TASK_COMPLETION
+};
+
+typedef void (*buffer_zero_dsa_completion_fn)(void *);
+
+typedef struct buffer_zero_batch_task {
+    struct dsa_hw_desc batch_descriptor;
+    struct dsa_hw_desc *descriptors;
+    struct dsa_completion_record batch_completion __attribute__((aligned(32)));
+    struct dsa_completion_record *completions;
+    struct dsa_device_group *group;
+    struct dsa_device *device;
+    buffer_zero_dsa_completion_fn completion_callback;
+    QemuSemaphore sem_task_complete;
+    enum dsa_task_type task_type;
+    enum dsa_task_status status;
+    bool *results;
+    int batch_size;
+    QSIMPLEQ_ENTRY(buffer_zero_batch_task) entry;
+} buffer_zero_batch_task;
+
+#else
+
+struct buffer_zero_batch_task {
+    bool *results;
+};
+
 #endif
 
 /**
diff --git a/util/dsa.c b/util/dsa.c
index 8edaa892ec..f82282ce99 100644
--- a/util/dsa.c
+++ b/util/dsa.c
@@ -245,6 +245,200 @@ dsa_device_group_get_next_device(struct dsa_device_group 
*group)
     return &group->dsa_devices[current];
 }
 
+/**
+ * @brief Empties out the DSA task queue.
+ *
+ * @param group A pointer to the DSA device group.
+ */
+static void
+dsa_empty_task_queue(struct dsa_device_group *group)
+{
+    qemu_mutex_lock(&group->task_queue_lock);
+    dsa_task_queue *task_queue = &group->task_queue;
+    while (!QSIMPLEQ_EMPTY(task_queue)) {
+        QSIMPLEQ_REMOVE_HEAD(task_queue, entry);
+    }
+    qemu_mutex_unlock(&group->task_queue_lock);
+}
+
+/**
+ * @brief Adds a task to the DSA task queue.
+ *
+ * @param group A pointer to the DSA device group.
+ * @param context A pointer to the DSA task to enqueue.
+ *
+ * @return int Zero if successful, otherwise a proper error code.
+ */
+static int
+dsa_task_enqueue(struct dsa_device_group *group,
+                 struct buffer_zero_batch_task *task)
+{
+    dsa_task_queue *task_queue = &group->task_queue;
+    QemuMutex *task_queue_lock = &group->task_queue_lock;
+    QemuCond *task_queue_cond = &group->task_queue_cond;
+
+    bool notify = false;
+
+    qemu_mutex_lock(task_queue_lock);
+
+    if (!group->running) {
+        fprintf(stderr, "DSA: Tried to queue task to stopped device queue\n");
+        qemu_mutex_unlock(task_queue_lock);
+        return -1;
+    }
+
+    // The queue is empty. This enqueue operation is a 0->1 transition.
+    if (QSIMPLEQ_EMPTY(task_queue))
+        notify = true;
+
+    QSIMPLEQ_INSERT_TAIL(task_queue, task, entry);
+
+    // We need to notify the waiter for 0->1 transitions.
+    if (notify)
+        qemu_cond_signal(task_queue_cond);
+
+    qemu_mutex_unlock(task_queue_lock);
+
+    return 0;
+}
+
+/**
+ * @brief Takes a DSA task out of the task queue.
+ *
+ * @param group A pointer to the DSA device group.
+ * @return buffer_zero_batch_task* The DSA task being dequeued.
+ */
+__attribute__((unused))
+static struct buffer_zero_batch_task *
+dsa_task_dequeue(struct dsa_device_group *group)
+{
+    struct buffer_zero_batch_task *task = NULL;
+    dsa_task_queue *task_queue = &group->task_queue;
+    QemuMutex *task_queue_lock = &group->task_queue_lock;
+    QemuCond *task_queue_cond = &group->task_queue_cond;
+
+    qemu_mutex_lock(task_queue_lock);
+
+    while (true) {
+        if (!group->running)
+            goto exit;
+        task = QSIMPLEQ_FIRST(task_queue);
+        if (task != NULL) {
+            break;
+        }
+        qemu_cond_wait(task_queue_cond, task_queue_lock);
+    }
+
+    QSIMPLEQ_REMOVE_HEAD(task_queue, entry);
+
+exit:
+    qemu_mutex_unlock(task_queue_lock);
+    return task;
+}
+
+/**
+ * @brief Submits a DSA work item to the device work queue.
+ *
+ * @param wq A pointer to the DSA work queue's device memory.
+ * @param descriptor A pointer to the DSA work item descriptor.
+ *
+ * @return Zero if successful, non-zero otherwise.
+ */
+static int
+submit_wi_int(void *wq, struct dsa_hw_desc *descriptor)
+{
+    uint64_t retry = 0;
+
+    _mm_sfence();
+
+    while (true) {
+        if (_enqcmd(wq, descriptor) == 0) {
+            break;
+        }
+        retry++;
+        if (retry > max_retry_count) {
+            fprintf(stderr, "Submit work retry %lu times.\n", retry);
+            exit(1);
+        }
+    }
+
+    return 0;
+}
+
+/**
+ * @brief Synchronously submits a DSA work item to the
+ *        device work queue.
+ *
+ * @param wq A pointer to the DSA worjk queue's device memory.
+ * @param descriptor A pointer to the DSA work item descriptor.
+ *
+ * @return int Zero if successful, non-zero otherwise.
+ */
+__attribute__((unused))
+static int
+submit_wi(void *wq, struct dsa_hw_desc *descriptor)
+{
+    return submit_wi_int(wq, descriptor);
+}
+
+/**
+ * @brief Asynchronously submits a DSA work item to the
+ *        device work queue.
+ *
+ * @param task A pointer to the buffer zero task.
+ *
+ * @return int Zero if successful, non-zero otherwise.
+ */
+__attribute__((unused))
+static int
+submit_wi_async(struct buffer_zero_batch_task *task)
+{
+    struct dsa_device_group *device_group = task->group;
+    struct dsa_device *device_instance = task->device;
+    int ret;
+
+    assert(task->task_type == DSA_TASK);
+
+    task->status = DSA_TASK_PROCESSING;
+
+    ret = submit_wi_int(device_instance->work_queue,
+                        &task->descriptors[0]);
+    if (ret != 0)
+        return ret;
+
+    return dsa_task_enqueue(device_group, task);
+}
+
+/**
+ * @brief Asynchronously submits a DSA batch work item to the
+ *        device work queue.
+ *
+ * @param batch_task A pointer to the batch buffer zero task.
+ *
+ * @return int Zero if successful, non-zero otherwise.
+ */
+__attribute__((unused))
+static int
+submit_batch_wi_async(struct buffer_zero_batch_task *batch_task)
+{
+    struct dsa_device_group *device_group = batch_task->group;
+    struct dsa_device *device_instance = batch_task->device;
+    int ret;
+
+    assert(batch_task->task_type == DSA_BATCH_TASK);
+    assert(batch_task->batch_descriptor.desc_count <= batch_task->batch_size);
+    assert(batch_task->status == DSA_TASK_READY);
+
+    batch_task->status = DSA_TASK_PROCESSING;
+
+    ret = submit_wi_int(device_instance->work_queue,
+                        &batch_task->batch_descriptor);
+    if (ret != 0)
+        return ret;
+
+    return dsa_task_enqueue(device_group, batch_task);
+}
+
 /**
  * @brief Check if DSA is running.
  *
@@ -301,6 +495,8 @@ void dsa_stop(void)
     if (!group->running) {
         return;
     }
+
+    dsa_empty_task_queue(group);
 }
 
 /**
-- 
2.30.2