* Add a DSA task completion callback. * DSA completion thread will call the tasks's completion callback on every task/batch task completion. * DSA submission path to wait for completion. * Implement CPU fallback if DSA is not able to complete the task.
Signed-off-by: Hao Xiang <hao.xi...@bytedance.com> Signed-off-by: Bryan Zhang <bryan.zh...@bytedance.com> --- include/qemu/dsa.h | 14 +++++ util/dsa.c | 153 ++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 164 insertions(+), 3 deletions(-) diff --git a/include/qemu/dsa.h b/include/qemu/dsa.h index b10e7b8fb7..3f8ee07004 100644 --- a/include/qemu/dsa.h +++ b/include/qemu/dsa.h @@ -65,6 +65,20 @@ void buffer_zero_batch_task_init(struct buffer_zero_batch_task *task, */ void buffer_zero_batch_task_destroy(struct buffer_zero_batch_task *task); +/** + * @brief Performs buffer zero comparison on a DSA batch task asynchronously. + * + * @param batch_task A pointer to the batch task. + * @param buf An array of memory buffers. + * @param count The number of buffers in the array. + * @param len The buffer length. + * + * @return Zero if successful, otherwise non-zero. + */ +int +buffer_is_zero_dsa_batch_async(struct buffer_zero_batch_task *batch_task, + const void **buf, size_t count, size_t len); + /** * @brief Initializes DSA devices. * diff --git a/util/dsa.c b/util/dsa.c index 3cc017b8a0..06c6fbf2ca 100644 --- a/util/dsa.c +++ b/util/dsa.c @@ -470,6 +470,41 @@ poll_completion(struct dsa_completion_record *completion, return 0; } +/** + * @brief Use CPU to complete a single zero page checking task. + * + * @param task A pointer to the task. + */ +static void +task_cpu_fallback(struct buffer_zero_batch_task *task) +{ + assert(task->task_type == DSA_TASK); + + struct dsa_completion_record *completion = &task->completions[0]; + const uint8_t *buf; + size_t len; + + if (completion->status == DSA_COMP_SUCCESS) { + return; + } + + /* + * DSA was able to partially complete the operation. Check the + * result. If we already know this is not a zero page, we can + * return now. + */ + if (completion->bytes_completed != 0 && completion->result != 0) { + task->results[0] = false; + return; + } + + /* Let's fallback to use CPU to complete it. */ + buf = (const uint8_t *)task->descriptors[0].src_addr; + len = task->descriptors[0].xfer_size; + task->results[0] = buffer_is_zero(buf + completion->bytes_completed, + len - completion->bytes_completed); +} + /** * @brief Complete a single DSA task in the batch task. * @@ -548,6 +583,62 @@ poll_batch_task_completion(struct buffer_zero_batch_task *batch_task) } } +/** + * @brief Use CPU to complete the zero page checking batch task. + * + * @param batch_task A pointer to the batch task. + */ +static void +batch_task_cpu_fallback(struct buffer_zero_batch_task *batch_task) +{ + assert(batch_task->task_type == DSA_BATCH_TASK); + + struct dsa_completion_record *batch_completion = + &batch_task->batch_completion; + struct dsa_completion_record *completion; + uint8_t status; + const uint8_t *buf; + size_t len; + bool *results = batch_task->results; + uint32_t count = batch_task->batch_descriptor.desc_count; + + // DSA is able to complete the entire batch task. + if (batch_completion->status == DSA_COMP_SUCCESS) { + assert(count == batch_completion->bytes_completed); + return; + } + + /* + * DSA encounters some error and is not able to complete + * the entire batch task. Use CPU fallback. + */ + for (int i = 0; i < count; i++) { + completion = &batch_task->completions[i]; + status = completion->status; + if (status == DSA_COMP_SUCCESS) { + continue; + } + assert(status == DSA_COMP_PAGE_FAULT_NOBOF); + + /* + * DSA was able to partially complete the operation. Check the + * result. If we already know this is not a zero page, we can + * return now. + */ + if (completion->bytes_completed != 0 && completion->result != 0) { + results[i] = false; + continue; + } + + /* Let's fallback to use CPU to complete it. */ + buf = (uint8_t *)batch_task->descriptors[i].src_addr; + len = batch_task->descriptors[i].xfer_size; + results[i] = + buffer_is_zero(buf + completion->bytes_completed, + len - completion->bytes_completed); + } +} + /** * @brief Handles an asynchronous DSA batch task completion. * @@ -825,7 +916,6 @@ buffer_zero_batch_task_set(struct buffer_zero_batch_task *batch_task, * * @return int Zero if successful, otherwise an appropriate error code. */ -__attribute__((unused)) static int buffer_zero_dsa_async(struct buffer_zero_batch_task *task, const void *buf, size_t len) @@ -844,7 +934,6 @@ buffer_zero_dsa_async(struct buffer_zero_batch_task *task, * @param count The number of buffers. * @param len The buffer length. */ -__attribute__((unused)) static int buffer_zero_dsa_batch_async(struct buffer_zero_batch_task *batch_task, const void **buf, size_t count, size_t len) @@ -876,13 +965,29 @@ buffer_zero_dsa_completion(void *context) * * @param batch_task A pointer to the buffer zero comparison batch task. */ -__attribute__((unused)) static void buffer_zero_dsa_wait(struct buffer_zero_batch_task *batch_task) { qemu_sem_wait(&batch_task->sem_task_complete); } +/** + * @brief Use CPU to complete the zero page checking task if DSA + * is not able to complete it. + * + * @param batch_task A pointer to the batch task. + */ +static void +buffer_zero_cpu_fallback(struct buffer_zero_batch_task *batch_task) +{ + if (batch_task->task_type == DSA_TASK) { + task_cpu_fallback(batch_task); + } else { + assert(batch_task->task_type == DSA_BATCH_TASK); + batch_task_cpu_fallback(batch_task); + } +} + /** * @brief Check if DSA is running. * @@ -956,6 +1061,41 @@ void dsa_cleanup(void) dsa_device_group_cleanup(&dsa_group); } +/** + * @brief Performs buffer zero comparison on a DSA batch task asynchronously. + * + * @param batch_task A pointer to the batch task. + * @param buf An array of memory buffers. + * @param count The number of buffers in the array. + * @param len The buffer length. + * + * @return Zero if successful, otherwise non-zero. + */ +int +buffer_is_zero_dsa_batch_async(struct buffer_zero_batch_task *batch_task, + const void **buf, size_t count, size_t len) +{ + if (count <= 0 || count > batch_task->batch_size) { + return -1; + } + + assert(batch_task != NULL); + assert(len != 0); + assert(buf != NULL); + + if (count == 1) { + // DSA doesn't take batch operation with only 1 task. + buffer_zero_dsa_async(batch_task, buf[0], len); + } else { + buffer_zero_dsa_batch_async(batch_task, buf, count, len); + } + + buffer_zero_dsa_wait(batch_task); + buffer_zero_cpu_fallback(batch_task); + + return 0; +} + #else void buffer_zero_batch_task_init(struct buffer_zero_batch_task *task, @@ -981,5 +1121,12 @@ void dsa_stop(void) {} void dsa_cleanup(void) {} +int +buffer_is_zero_dsa_batch_async(struct buffer_zero_batch_task *batch_task, + const void **buf, size_t count, size_t len) +{ + exit(1); +} + #endif -- 2.30.2