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Tsirkin" , Cornelia Huck , qemu-devel@nongnu.org Cc: "Hao Xiang" , "Liu, Yuan1" , "Shivam Kumar" , "Ho-Ren (Jack) Chuang" , "Yichen Wang" , Bryan Zhang Subject: [PATCH v6 07/12] util/dsa: Implement DSA task asynchronous submission and wait for completion. Date: Wed, 9 Oct 2024 16:46:05 -0700 Message-Id: <20241009234610.27039-8-yichen.wang@bytedance.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20241009234610.27039-1-yichen.wang@bytedance.com> References: <20241009234610.27039-1-yichen.wang@bytedance.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::830; envelope-from=yichen.wang@bytedance.com; helo=mail-qt1-x830.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Hao Xiang * 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 Signed-off-by: Bryan Zhang Signed-off-by: Yichen Wang --- include/qemu/dsa.h | 14 +++++ util/dsa.c | 125 +++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 135 insertions(+), 4 deletions(-) diff --git a/include/qemu/dsa.h b/include/qemu/dsa.h index 89841a6ffa..a3b502ee41 100644 --- a/include/qemu/dsa.h +++ b/include/qemu/dsa.h @@ -123,6 +123,20 @@ buffer_zero_batch_task_init(int batch_size); */ void buffer_zero_batch_task_destroy(QemuDsaBatchTask *task); +/** + * @brief Performs buffer zero comparison on a DSA batch task synchronously. + * + * @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_sync(QemuDsaBatchTask *batch_task, + const void **buf, size_t count, size_t len); + #else typedef struct QemuDsaBatchTask {} QemuDsaBatchTask; diff --git a/util/dsa.c b/util/dsa.c index d9c066ff00..cbaa47c360 100644 --- a/util/dsa.c +++ b/util/dsa.c @@ -435,6 +435,42 @@ poll_completion(struct dsa_completion_record *completion, return 0; } +/** + * @brief Helper function to use CPU to complete a single + * zero page checking task. + * + * @param completion A pointer to a DSA task completion record. + * @param descriptor A pointer to a DSA task descriptor. + * @param result A pointer to the result of a zero page checking. + */ +static void +task_cpu_fallback_int(struct dsa_completion_record *completion, + struct dsa_hw_desc *descriptor, bool *result) +{ + 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) { + *result = false; + return; + } + + /* Let's fallback to use CPU to complete it. */ + buf = (const uint8_t *)descriptor->src_addr; + len = descriptor->xfer_size; + *result = buffer_is_zero(buf + completion->bytes_completed, + len - completion->bytes_completed); +} + /** * @brief Complete a single DSA task in the batch task. * @@ -563,7 +599,7 @@ dsa_completion_loop(void *opaque) (QemuDsaCompletionThread *)opaque; QemuDsaBatchTask *batch_task; QemuDsaDeviceGroup *group = thread_context->group; - int ret; + int ret = 0; rcu_register_thread(); @@ -831,7 +867,6 @@ buffer_zero_batch_task_set(QemuDsaBatchTask *batch_task, * * @return int Zero if successful, otherwise an appropriate error code. */ -__attribute__((unused)) static int buffer_zero_dsa_async(QemuDsaBatchTask *task, const void *buf, size_t len) @@ -850,7 +885,6 @@ buffer_zero_dsa_async(QemuDsaBatchTask *task, * @param count The number of buffers. * @param len The buffer length. */ -__attribute__((unused)) static int buffer_zero_dsa_batch_async(QemuDsaBatchTask *batch_task, const void **buf, size_t count, size_t len) @@ -881,13 +915,61 @@ 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(QemuDsaBatchTask *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(QemuDsaBatchTask *batch_task) +{ + if (batch_task->task_type == QEMU_DSA_TASK) { + if (batch_task->completions[0].status == DSA_COMP_SUCCESS) { + return; + } + task_cpu_fallback_int(&batch_task->completions[0], + &batch_task->descriptors[0], + &batch_task->results[0]); + } else if (batch_task->task_type == QEMU_DSA_BATCH_TASK) { + struct dsa_completion_record *batch_completion = + &batch_task->batch_completion; + struct dsa_completion_record *completion; + uint8_t status; + 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; + + assert(status == DSA_COMP_SUCCESS || + status == DSA_COMP_PAGE_FAULT_NOBOF); + + task_cpu_fallback_int(completion, + &batch_task->descriptors[i], + &results[i]); + } + } +} + /** * @brief Initializes a buffer zero comparison DSA task. * @@ -964,3 +1046,38 @@ buffer_zero_batch_task_destroy(QemuDsaBatchTask *task) qemu_sem_destroy(&task->sem_task_complete); qemu_vfree(task); } + +/** + * @brief Performs buffer zero comparison on a DSA batch task synchronously. + * + * @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_sync(QemuDsaBatchTask *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; +}