From: Changpeng Liu <changpeng.liu@intel.com>
To: dev@dpdk.org
Cc: Changpeng Liu <changpeng.liu@intel.com>,
Maxime Coquelin <maxime.coquelin@redhat.com>,
Chenbo Xia <chenbo.xia@intel.com>,
David Marchand <david.marchand@redhat.com>
Subject: [PATCH v4] vhost: add new `rte_vhost_vring_call_nonblock` API
Date: Mon, 17 Oct 2022 15:48:17 +0800 [thread overview]
Message-ID: <20221017074817.28889-1-changpeng.liu@intel.com> (raw)
In-Reply-To: <20221017071457.28589-1-changpeng.liu@intel.com>
Vhost-user library locks all VQ's access lock when processing
vring based messages, such as SET_VRING_KICK and SET_VRING_CALL,
and the data processing thread may already be started, e.g: SPDK
vhost-blk and vhost-scsi will start the data processing thread
when one vring is ready, then deadlock may happen when SPDK is
posting interrupts to VM. Here, we add a new API which allows
caller to try again later for this case.
Bugzilla ID: 1015
Fixes: c5736998305d ("vhost: fix missing virtqueue lock protection")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
---
doc/guides/prog_guide/vhost_lib.rst | 6 ++++++
doc/guides/rel_notes/release_22_11.rst | 6 ++++++
lib/vhost/rte_vhost.h | 15 +++++++++++++
lib/vhost/version.map | 3 +++
lib/vhost/vhost.c | 30 ++++++++++++++++++++++++++
5 files changed, 60 insertions(+)
diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index bad4d819e1..52f0589f51 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -297,6 +297,12 @@ The following is an overview of some key Vhost API functions:
Clear in-flight packets which are submitted to async channel in vhost async data
path. Completed packets are returned to applications through ``pkts``.
+* ``rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx)``
+
+ Notify the guest that used descriptors have been added to the vring. This function
+ will return -EAGAIN when vq's access lock is held by other thread, user should try
+ again later.
+
* ``rte_vhost_vring_stats_get_names(int vid, uint16_t queue_id, struct rte_vhost_stat_name *names, unsigned int size)``
This function returns the names of the queue statistics. It requires
diff --git a/doc/guides/rel_notes/release_22_11.rst b/doc/guides/rel_notes/release_22_11.rst
index 2da8bc9661..b3d1ba043c 100644
--- a/doc/guides/rel_notes/release_22_11.rst
+++ b/doc/guides/rel_notes/release_22_11.rst
@@ -225,6 +225,12 @@ New Features
sysfs entries to adjust the minimum and maximum uncore frequency values,
which works on Linux with Intel hardware only.
+* **Added non-blocking notify API to the vhost library.**
+
+ Added ``rte_vhost_vring_call_nonblock`` API to notify the guest that
+ used descriptors have been added to the vring in non-blocking way. User
+ should check the return value of this API and try again if needed.
+
* **Rewritten pmdinfo script.**
The ``dpdk-pmdinfo.py`` script was rewritten to produce valid JSON only.
diff --git a/lib/vhost/rte_vhost.h b/lib/vhost/rte_vhost.h
index bb7d86a432..d22b25cd4e 100644
--- a/lib/vhost/rte_vhost.h
+++ b/lib/vhost/rte_vhost.h
@@ -909,6 +909,21 @@ rte_vhost_clr_inflight_desc_packed(int vid, uint16_t vring_idx,
*/
int rte_vhost_vring_call(int vid, uint16_t vring_idx);
+/**
+ * Notify the guest that used descriptors have been added to the vring. This
+ * function acts as a memory barrier. This function will return -EAGAIN when
+ * vq's access lock is held by other thread, user should try again later.
+ *
+ * @param vid
+ * vhost device ID
+ * @param vring_idx
+ * vring index
+ * @return
+ * 0 on success, -1 on failure, -EAGAIN for another retry
+ */
+__rte_experimental
+int rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx);
+
/**
* Get vhost RX queue avail count.
*
diff --git a/lib/vhost/version.map b/lib/vhost/version.map
index 7a00b65740..c8c44b8326 100644
--- a/lib/vhost/version.map
+++ b/lib/vhost/version.map
@@ -94,6 +94,9 @@ EXPERIMENTAL {
rte_vhost_async_try_dequeue_burst;
rte_vhost_driver_get_vdpa_dev_type;
rte_vhost_clear_queue;
+
+ # added in 22.11
+ rte_vhost_vring_call_nonblock;
};
INTERNAL {
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 8740aa2788..ed6efb003f 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1317,6 +1317,36 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
return 0;
}
+int
+rte_vhost_vring_call_nonblock(int vid, uint16_t vring_idx)
+{
+ struct virtio_net *dev;
+ struct vhost_virtqueue *vq;
+
+ dev = get_device(vid);
+ if (!dev)
+ return -1;
+
+ if (vring_idx >= VHOST_MAX_VRING)
+ return -1;
+
+ vq = dev->virtqueue[vring_idx];
+ if (!vq)
+ return -1;
+
+ if (!rte_spinlock_trylock(&vq->access_lock))
+ return -EAGAIN;
+
+ if (vq_is_packed(dev))
+ vhost_vring_call_packed(dev, vq);
+ else
+ vhost_vring_call_split(dev, vq);
+
+ rte_spinlock_unlock(&vq->access_lock);
+
+ return 0;
+}
+
uint16_t
rte_vhost_avail_entries(int vid, uint16_t queue_id)
{
--
2.21.3
next prev parent reply other threads:[~2022-10-17 7:48 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 2:22 [PATCH] vhost: use try_lock in rte_vhost_vring_call Changpeng Liu
2022-09-06 21:15 ` Stephen Hemminger
2022-09-07 0:40 ` Liu, Changpeng
2022-09-20 7:12 ` Maxime Coquelin
2022-09-20 2:24 ` Xia, Chenbo
2022-09-20 2:34 ` Liu, Changpeng
2022-09-20 2:53 ` Xia, Chenbo
2022-09-20 3:00 ` Liu, Changpeng
2022-09-20 7:23 ` Maxime Coquelin
2022-09-20 7:30 ` Maxime Coquelin
2022-09-20 7:19 ` Maxime Coquelin
2022-09-20 7:29 ` Liu, Changpeng
2022-09-20 7:34 ` Maxime Coquelin
2022-09-20 7:45 ` Liu, Changpeng
2022-09-20 8:12 ` Maxime Coquelin
2022-09-20 8:43 ` Liu, Changpeng
2022-09-21 9:41 ` Maxime Coquelin
2022-09-21 9:52 ` Liu, Changpeng
2022-10-11 11:56 ` Maxime Coquelin
2022-10-12 6:40 ` [PATCH v2] vhost: add new `rte_vhost_vring_call_nonblock` API Changpeng Liu
2022-10-13 7:56 ` Maxime Coquelin
2022-10-17 6:46 ` Xia, Chenbo
2022-10-17 7:17 ` Liu, Changpeng
2022-10-17 7:14 ` [PATCH v3] " Changpeng Liu
2022-10-17 7:39 ` Xia, Chenbo
2022-10-17 7:50 ` Liu, Changpeng
2022-10-17 7:48 ` Changpeng Liu [this message]
2022-10-19 5:27 ` [PATCH v4] " Xia, Chenbo
2022-10-26 9:24 ` Xia, Chenbo
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