[PATCH v3 1/2] vhost: introduce DMA vchannel unconfiguration

[xuan.ding@intel.com]

From: Xuan Ding <xuan.ding@intel.com>

This patch adds a new API rte_vhost_async_dma_unconfigure() to unconfigure
DMA vchannels in vhost async data path.

Lock protection are also added to protect DMA vchannels configuration and
unconfiguration from concurrent calls.

Signed-off-by: Xuan Ding <xuan.ding@intel.com>
---
 doc/guides/prog_guide/vhost_lib.rst    |  6 +++
 doc/guides/rel_notes/release_22_11.rst |  3 ++
 lib/vhost/rte_vhost_async.h            | 18 +++++++
 lib/vhost/version.map                  |  3 ++
 lib/vhost/vhost.c                      | 69 ++++++++++++++++++++++++--
 5 files changed, 94 insertions(+), 5 deletions(-)

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index bad4d819e1..d3cef978d0 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -323,6 +323,12 @@ The following is an overview of some key Vhost API functions:
   Get device type of vDPA device, such as VDPA_DEVICE_TYPE_NET,
   VDPA_DEVICE_TYPE_BLK.
 
+* ``rte_vhost_async_dma_unconfigure(dma_id, vchan_id)``
+
+  Clean DMA vChannels finished to use. This function needs to
+  be called after the deregistration of async DMA vchannel
+  has been finished.
+
 Vhost-user Implementations
 --------------------------
 
diff --git a/doc/guides/rel_notes/release_22_11.rst b/doc/guides/rel_notes/release_22_11.rst
index 684bf74596..a641d8a6b8 100644
--- a/doc/guides/rel_notes/release_22_11.rst
+++ b/doc/guides/rel_notes/release_22_11.rst
@@ -67,6 +67,9 @@ New Features
 
   * Added support to set device link down/up.
 
+* **Added DMA vChannel unconfiguration for async vhost.**
+
+  * Added support to unconfigure DMA vChannels that have been unregistered.
 
 Removed Items
 -------------
diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
index 1db2a10124..6ee4f7258d 100644
--- a/lib/vhost/rte_vhost_async.h
+++ b/lib/vhost/rte_vhost_async.h
@@ -266,6 +266,24 @@ rte_vhost_async_try_dequeue_burst(int vid, uint16_t queue_id,
 	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count,
 	int *nr_inflight, int16_t dma_id, uint16_t vchan_id);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice.
+ *
+ * Unconfigure DMA vChannels in asynchronous data path.
+ * This function should be called after the DMA vChannel has been unregistered.
+ *
+ * @param dma_id
+ *  the identifier of DMA device
+ * @param vchan_id
+ *  the identifier of virtual DMA channel
+ * @return
+ *  0 on success, and -1 on failure
+ */
+__rte_experimental
+int
+rte_vhost_async_dma_unconfigure(int16_t dma_id, uint16_t vchan_id);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/vhost/version.map b/lib/vhost/version.map
index 18574346d5..013a6bcc42 100644
--- a/lib/vhost/version.map
+++ b/lib/vhost/version.map
@@ -96,6 +96,9 @@ EXPERIMENTAL {
 	rte_vhost_async_try_dequeue_burst;
 	rte_vhost_driver_get_vdpa_dev_type;
 	rte_vhost_clear_queue;
+
+	# added in 22.11
+	rte_vhost_async_dma_unconfigure;
 };
 
 INTERNAL {
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index aa671f47a3..f0f337bf5b 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -23,6 +23,7 @@
 
 struct virtio_net *vhost_devices[RTE_MAX_VHOST_DEVICE];
 pthread_mutex_t vhost_dev_lock = PTHREAD_MUTEX_INITIALIZER;
+static rte_spinlock_t vhost_dma_lock = RTE_SPINLOCK_INITIALIZER;
 
 struct vhost_vq_stats_name_off {
 	char name[RTE_VHOST_STATS_NAME_SIZE];
@@ -1850,19 +1851,20 @@ rte_vhost_async_dma_configure(int16_t dma_id, uint16_t vchan_id)
 	void *pkts_cmpl_flag_addr;
 	uint16_t max_desc;
 
+	rte_spinlock_lock(&vhost_dma_lock);
 	if (!rte_dma_is_valid(dma_id)) {
 		VHOST_LOG_CONFIG("dma", ERR, "DMA %d is not found.\n", dma_id);
-		return -1;
+		goto error;
 	}
 
 	if (rte_dma_info_get(dma_id, &info) != 0) {
 		VHOST_LOG_CONFIG("dma", ERR, "Fail to get DMA %d information.\n", dma_id);
-		return -1;
+		goto error;
 	}
 
 	if (vchan_id >= info.max_vchans) {
 		VHOST_LOG_CONFIG("dma", ERR, "Invalid DMA %d vChannel %u.\n", dma_id, vchan_id);
-		return -1;
+		goto error;
 	}
 
 	if (!dma_copy_track[dma_id].vchans) {
@@ -1874,7 +1876,7 @@ rte_vhost_async_dma_configure(int16_t dma_id, uint16_t vchan_id)
 			VHOST_LOG_CONFIG("dma", ERR,
 				"Failed to allocate vchans for DMA %d vChannel %u.\n",
 				dma_id, vchan_id);
-			return -1;
+			goto error;
 		}
 
 		dma_copy_track[dma_id].vchans = vchans;
@@ -1883,6 +1885,7 @@ rte_vhost_async_dma_configure(int16_t dma_id, uint16_t vchan_id)
 	if (dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr) {
 		VHOST_LOG_CONFIG("dma", INFO, "DMA %d vChannel %u already registered.\n",
 			dma_id, vchan_id);
+		rte_spinlock_unlock(&vhost_dma_lock);
 		return 0;
 	}
 
@@ -1900,7 +1903,7 @@ rte_vhost_async_dma_configure(int16_t dma_id, uint16_t vchan_id)
 			rte_free(dma_copy_track[dma_id].vchans);
 			dma_copy_track[dma_id].vchans = NULL;
 		}
-		return -1;
+		goto error;
 	}
 
 	dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr = pkts_cmpl_flag_addr;
@@ -1908,7 +1911,12 @@ rte_vhost_async_dma_configure(int16_t dma_id, uint16_t vchan_id)
 	dma_copy_track[dma_id].vchans[vchan_id].ring_mask = max_desc - 1;
 	dma_copy_track[dma_id].nr_vchans++;
 
+	rte_spinlock_unlock(&vhost_dma_lock);
 	return 0;
+
+error:
+	rte_spinlock_unlock(&vhost_dma_lock);
+	return -1;
 }
 
 int
@@ -2097,5 +2105,56 @@ int rte_vhost_vring_stats_reset(int vid, uint16_t queue_id)
 	return 0;
 }
 
+int
+rte_vhost_async_dma_unconfigure(int16_t dma_id, uint16_t vchan_id)
+{
+	struct rte_dma_info info;
+	uint16_t max_desc;
+	int i;
+
+	rte_spinlock_lock(&vhost_dma_lock);
+	if (!rte_dma_is_valid(dma_id)) {
+		VHOST_LOG_CONFIG("dma", ERR, "DMA %d is not found.\n", dma_id);
+		goto error;
+	}
+
+	if (rte_dma_info_get(dma_id, &info) != 0) {
+		VHOST_LOG_CONFIG("dma", ERR, "Fail to get DMA %d information.\n", dma_id);
+		goto error;
+	}
+
+	if (vchan_id >= info.max_vchans) {
+		VHOST_LOG_CONFIG("dma", ERR, "Invalid DMA %d vChannel %u.\n", dma_id, vchan_id);
+		goto error;
+	}
+
+	max_desc = info.max_desc;
+	for (i = 0; i < max_desc; i++) {
+		if (dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr[i] != NULL) {
+			rte_free(dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr[i]);
+			dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr[i] = NULL;
+		}
+	}
+
+	if (dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr != NULL) {
+		rte_free(dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr);
+		dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr = NULL;
+	}
+
+	if (dma_copy_track[dma_id].vchans != NULL) {
+		rte_free(dma_copy_track[dma_id].vchans);
+		dma_copy_track[dma_id].vchans = NULL;
+	}
+
+	dma_copy_track[dma_id].nr_vchans--;
+
+	rte_spinlock_unlock(&vhost_dma_lock);
+	return 0;
+
+error:
+	rte_spinlock_unlock(&vhost_dma_lock);
+	return -1;
+}
+
 RTE_LOG_REGISTER_SUFFIX(vhost_config_log_level, config, INFO);
 RTE_LOG_REGISTER_SUFFIX(vhost_data_log_level, data, WARNING);
-- 
2.17.1