RE: [PATCH v2 1/2] vhost: introduce DMA vchannel unconfiguration

["Ding, Xuan" <xuan.ding@intel.com>]

Hi Chenbo,

Thanks for your comments, please see replies inline.

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia@intel.com>
> Sent: Monday, September 26, 2022 2:07 PM
> To: Ding, Xuan <xuan.ding@intel.com>; maxime.coquelin@redhat.com
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; He, Xingguang
> <xingguang.he@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>;
> Jiang, Cheng1 <cheng1.jiang@intel.com>; Wang, YuanX
> <yuanx.wang@intel.com>; Ma, WenwuX <wenwux.ma@intel.com>
> Subject: RE: [PATCH v2 1/2] vhost: introduce DMA vchannel unconfiguration
> 
> > -----Original Message-----
> > From: Ding, Xuan <xuan.ding@intel.com>
> > Sent: Tuesday, September 6, 2022 1:22 PM
> > To: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
> > Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; He, Xingguang
> > <xingguang.he@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>;
> > Jiang,
> > Cheng1 <cheng1.jiang@intel.com>; Wang, YuanX <yuanx.wang@intel.com>;
> > Ma, WenwuX <wenwux.ma@intel.com>; Ding, Xuan <xuan.ding@intel.com>
> > Subject: [PATCH v2 1/2] vhost: introduce DMA vchannel unconfiguration
> >
> > 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    |  5 ++
> >  doc/guides/rel_notes/release_22_11.rst |  2 +
> >  lib/vhost/rte_vhost_async.h            | 17 +++++++
> >  lib/vhost/version.map                  |  3 ++
> >  lib/vhost/vhost.c                      | 69 ++++++++++++++++++++++++--
> >  5 files changed, 91 insertions(+), 5 deletions(-)
> >
> > diff --git a/doc/guides/prog_guide/vhost_lib.rst
> > b/doc/guides/prog_guide/vhost_lib.rst
> > index bad4d819e1..22764cbeaa 100644
> > --- a/doc/guides/prog_guide/vhost_lib.rst
> > +++ b/doc/guides/prog_guide/vhost_lib.rst
> > @@ -323,6 +323,11 @@ 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)``
> > +
> > +  Clear DMA vChannels finished to use. This function needs to  be
> > + called after the deregisterration of async path has been finished.
> 
> Deregistration

Thanks for your catch.

> 
> > +
> >  Vhost-user Implementations
> >  --------------------------
> >
> > diff --git a/doc/guides/rel_notes/release_22_11.rst
> > b/doc/guides/rel_notes/release_22_11.rst
> > index 8c021cf050..e94c006e39 100644
> > --- a/doc/guides/rel_notes/release_22_11.rst
> > +++ b/doc/guides/rel_notes/release_22_11.rst
> > @@ -55,6 +55,8 @@ New Features
> >       Also, make sure to start the actual text at the margin.
> >       =======================================================
> >
> > +* **Added vhost API to unconfigure DMA vchannels.**
> > +  Added an API which helps to unconfigure DMA vchannels.
> 
> Added XXX for async vhost

Good idea.

> 
> Overall LGTM. It seems it needs some rebasing too.

I'm preparing v3 patch series, please see next version.

Regards,
Xuan

> 
> Thanks,
> Chenbo
> 
> >
> >  Removed Items
> >  -------------
> > diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
> > index 1db2a10124..0442e027fd 100644
> > --- a/lib/vhost/rte_vhost_async.h
> > +++ b/lib/vhost/rte_vhost_async.h
> > @@ -266,6 +266,23 @@ 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.
> > + *
> > + * @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
> > 60cb05a0ff..273616da11 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]; @@ -1870,19 +1871,20
> @@
> > 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) { @@ -1894,7 +1896,7 @@
> > 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; @@ -1903,6
> +1905,7 @@
> > 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;
> >  	}
> >
> > @@ -1920,7 +1923,7 @@ 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; @@ -1928,7 +1931,12 @@
> > 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
> > @@ -2117,5 +2125,56 @@ 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