[dpdk-stable] patch 'vhost: fix interrupt suppression for the split ring' has been queued to LTS release 18.11.2

[Kevin Traynor]

Hi,

FYI, your patch has been queued to LTS release 18.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 04/24/19. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Kevin Traynor

---
>From 771777c9191f025077b60ee93d5d747f7e63d571 Mon Sep 17 00:00:00 2001
From: Jiayu Hu <jiayu.hu at intel.com>
Date: Sun, 17 Mar 2019 14:38:32 +0800
Subject: [PATCH] vhost: fix interrupt suppression for the split ring

[ upstream commit 2f706027c8ee1bfcf4895cc35a42f0d2270dc819 ]

The VIRTIO_RING_F_EVENT_IDX feature of split ring might
be broken, as the value of signalled_used is invalid
after live migration, start up and virtio driver reload.
This patch fixes it by using signalled_used_valid.

In addition, this patch makes the VIRTIO_RING_F_EVENT_IDX
implementation of split ring match kernel backend to suppress
more interrupts.

Fixes: e37ff954405a ("vhost: support virtqueue interrupt/notification suppression")

Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
Tested-by: Yinan Wang <yinan.wang at intel.com>
Reviewed-by: Tiwei Bie <tiwei.bie at intel.com>
---
 lib/librte_vhost/vhost.h      | 12 ++++++++----
 lib/librte_vhost/vhost_user.c |  2 ++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 0f9fc9edd..bb9cff9f7 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -687,4 +687,8 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
 		uint16_t old = vq->signalled_used;
 		uint16_t new = vq->last_used_idx;
+		bool signalled_used_valid = vq->signalled_used_valid;
+
+		vq->signalled_used = new;
+		vq->signalled_used_valid = true;
 
 		VHOST_LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
@@ -692,9 +696,9 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
 			vhost_used_event(vq),
 			old, new);
-		if (vhost_need_event(vhost_used_event(vq), new, old)
-			&& (vq->callfd >= 0)) {
-			vq->signalled_used = vq->last_used_idx;
+
+		if ((vhost_need_event(vhost_used_event(vq), new, old) &&
+					(vq->callfd >= 0)) ||
+				unlikely(!signalled_used_valid))
 			eventfd_write(vq->callfd, (eventfd_t) 1);
-		}
 	} else {
 		/* Kick the guest if necessary. */
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 2d1123e60..7952ef700 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1299,4 +1299,6 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
 	vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
 
+	vq->signalled_used_valid = false;
+
 	if (dev->dequeue_zero_copy)
 		free_zmbufs(vq);
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2019-04-16 15:34:26.574932928 +0100
+++ 0031-vhost-fix-interrupt-suppression-for-the-split-ring.patch	2019-04-16 15:34:25.177180016 +0100
@@ -1,8 +1,10 @@
-From 2f706027c8ee1bfcf4895cc35a42f0d2270dc819 Mon Sep 17 00:00:00 2001
+From 771777c9191f025077b60ee93d5d747f7e63d571 Mon Sep 17 00:00:00 2001
 From: Jiayu Hu <jiayu.hu at intel.com>
 Date: Sun, 17 Mar 2019 14:38:32 +0800
 Subject: [PATCH] vhost: fix interrupt suppression for the split ring
 
+[ upstream commit 2f706027c8ee1bfcf4895cc35a42f0d2270dc819 ]
+
 The VIRTIO_RING_F_EVENT_IDX feature of split ring might
 be broken, as the value of signalled_used is invalid
 after live migration, start up and virtio driver reload.
@@ -13,7 +15,6 @@
 more interrupts.
 
 Fixes: e37ff954405a ("vhost: support virtqueue interrupt/notification suppression")
-Cc: stable at dpdk.org
 
 Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
 Tested-by: Yinan Wang <yinan.wang at intel.com>
@@ -24,10 +25,10 @@
  2 files changed, 10 insertions(+), 4 deletions(-)
 
 diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
-index f008ec43b..e9138dfab 100644
+index 0f9fc9edd..bb9cff9f7 100644
 --- a/lib/librte_vhost/vhost.h
 +++ b/lib/librte_vhost/vhost.h
-@@ -634,4 +634,8 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
+@@ -687,4 +687,8 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
  		uint16_t old = vq->signalled_used;
  		uint16_t new = vq->last_used_idx;
 +		bool signalled_used_valid = vq->signalled_used_valid;
@@ -36,7 +37,7 @@
 +		vq->signalled_used_valid = true;
  
  		VHOST_LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
-@@ -639,9 +643,9 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
+@@ -692,9 +696,9 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
  			vhost_used_event(vq),
  			old, new);
 -		if (vhost_need_event(vhost_used_event(vq), new, old)
@@ -51,7 +52,7 @@
  	} else {
  		/* Kick the guest if necessary. */
 diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
-index 555d09ad9..4f215769f 100644
+index 2d1123e60..7952ef700 100644
 --- a/lib/librte_vhost/vhost_user.c
 +++ b/lib/librte_vhost/vhost_user.c
 @@ -1299,4 +1299,6 @@ vhost_user_get_vring_base(struct virtio_net **pdev,