[PATCH v4] vhost: support virtqueue interrupt/notification suppression

[PATCH v4] vhost: support virtqueue interrupt/notification suppression

[junjie.j.chen]

From: Junjie Chen <junjie.j.chen@intel.com>

The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
negotiated. The driver set vring flags to 0, and MAY use used_event in
available ring to advise device interrupt util reach an index specified
by used_event. The device ignore the lower bit of vring flags, and send
an interrupt when index reach used_event.

The device can suppress notification in a manner analogous to the ways
driver suppress interrupt. The device manipulates flags or avail_event in
the used ringin the same way the driver manipulates flags or used_event in
available ring.

This patch is to enable this feature in vhost.

Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
---
 lib/librte_vhost/Makefile     |  1 +
 lib/librte_vhost/vhost.h      |  3 +++
 lib/librte_vhost/virtio_net.c | 56 +++++++++++++++++++++++++++++++------------
 3 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
index be182798a..85695d443 100644
--- a/lib/librte_vhost/Makefile
+++ b/lib/librte_vhost/Makefile
@@ -40,6 +40,7 @@ LIBABIVER := 4
 
 CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
 CFLAGS += -I vhost_user
+CFLAGS += -fno-strict-aliasing
 LDLIBS += -lpthread
 
 ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 1cc81c17c..fc41c205f 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -103,6 +103,8 @@ struct vhost_virtqueue {
 
 	uint16_t		last_avail_idx;
 	uint16_t		last_used_idx;
+	/* Last used index we notify to front end. */
+	uint16_t		signalled_used;
 #define VIRTIO_INVALID_EVENTFD		(-1)
 #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
 
@@ -211,6 +213,7 @@ struct vhost_msg {
 				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
 				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
+				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
 				(1ULL << VIRTIO_NET_F_MTU) | \
 				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
 
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6fee16e55..a3895658f 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -52,6 +52,35 @@
 
 #define MAX_BATCH_LEN 256
 
+#define vhost_used_event(vr)  ((vr)->avail->ring[(vr)->size])
+#define vhost_avail_event(vr) \
+	(*(volatile uint16_t *)&(vr)->used->ring[(vr)->size])
+
+static __rte_always_inline void
+vhost_notify(struct virtio_net *dev,  struct vhost_virtqueue *vq)
+{
+	/* Don't notify guest if we don't reach index specified by guest. */
+	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
+		uint16_t old = vq->signalled_used;
+		uint16_t new = vq->last_used_idx;
+
+		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
+			__func__,
+			vhost_used_event(vq),
+			old, new);
+		if (vring_need_event(vhost_used_event(vq), new, old)
+			&& (vq->callfd >= 0)) {
+			vq->signalled_used = vq->last_used_idx;
+			eventfd_write(vq->callfd, (eventfd_t) 1);
+		}
+	} else {
+		/* Kick the guest if necessary. */
+		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+			&& (vq->callfd >= 0))
+			eventfd_write(vq->callfd, (eventfd_t)1);
+	}
+}
+
 static bool
 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
 {
@@ -410,11 +439,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 
 	/* flush used->idx update before we read avail->flags. */
 	rte_mb();
-
-	/* Kick the guest if necessary. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	vhost_notify(dev, vq);
 out:
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 		vhost_user_iotlb_rd_unlock(vq);
@@ -704,11 +729,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 
 		/* flush used->idx update before we read avail->flags. */
 		rte_mb();
-
-		/* Kick the guest if necessary. */
-		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-				&& (vq->callfd >= 0))
-			eventfd_write(vq->callfd, (eventfd_t)1);
+		vhost_notify(dev, vq);
 	}
 
 out:
@@ -1106,11 +1127,7 @@ update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	vq->used->idx += count;
 	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 			sizeof(vq->used->idx));
-
-	/* Kick guest if required. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	vhost_notify(dev, vq);
 }
 
 static __rte_always_inline struct zcopy_mbuf *
@@ -1352,6 +1369,15 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 		update_used_idx(dev, vq, i);
 	}
 
+	/*
+	 * Update avail event index to last_avail_idx to expect
+	 * front end notify us after next buffer available.
+	 */
+	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
+		vhost_avail_event(vq) = vq->last_avail_idx;
+		rte_mb();
+	}
+
 out:
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 		vhost_user_iotlb_rd_unlock(vq);
-- 
2.15.0

[PATCH v5] vhost: support virtqueue interrupt/notification suppression

[Junjie Chen]

The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
negotiated. The driver set vring flags to 0, and MAY use used_event in
available ring to advise device interrupt util reach an index specified
by used_event. The device ignore the lower bit of vring flags, and send
an interrupt when index reach used_event.

The device can suppress notification in a manner analogous to the ways
driver suppress interrupt. The device manipulates flags or avail_event in
the used ringin the same way the driver manipulates flags or used_event in
available ring.

This patch is to enable this feature in vhost.

Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>

v5:
Remove updating avail event index in backend.

v2-v4:
Use definition of VIRTIO_F_EVENT_IDX from kernel.

---
 lib/librte_vhost/Makefile     |  1 +
 lib/librte_vhost/vhost.h      |  3 +++
 lib/librte_vhost/virtio_net.c | 47 +++++++++++++++++++++++++++++--------------
 3 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
index be18279..85695d4 100644
--- a/lib/librte_vhost/Makefile
+++ b/lib/librte_vhost/Makefile
@@ -40,6 +40,7 @@ LIBABIVER := 4
 
 CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
 CFLAGS += -I vhost_user
+CFLAGS += -fno-strict-aliasing
 LDLIBS += -lpthread
 
 ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 1cc81c1..fc41c20 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -103,6 +103,8 @@ struct vhost_virtqueue {
 
 	uint16_t		last_avail_idx;
 	uint16_t		last_used_idx;
+	/* Last used index we notify to front end. */
+	uint16_t		signalled_used;
 #define VIRTIO_INVALID_EVENTFD		(-1)
 #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
 
@@ -211,6 +213,7 @@ struct vhost_msg {
 				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
 				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
+				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
 				(1ULL << VIRTIO_NET_F_MTU) | \
 				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
 
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6fee16e..2badeda 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -52,6 +52,35 @@
 
 #define MAX_BATCH_LEN 256
 
+#define vhost_used_event(vr)  ((vr)->avail->ring[(vr)->size])
+#define vhost_avail_event(vr) \
+	(*(volatile uint16_t *)&(vr)->used->ring[(vr)->size])
+
+static __rte_always_inline void
+vhost_notify(struct virtio_net *dev,  struct vhost_virtqueue *vq)
+{
+	/* Don't notify guest if we don't reach index specified by guest. */
+	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
+		uint16_t old = vq->signalled_used;
+		uint16_t new = vq->last_used_idx;
+
+		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
+			__func__,
+			vhost_used_event(vq),
+			old, new);
+		if (vring_need_event(vhost_used_event(vq), new, old)
+			&& (vq->callfd >= 0)) {
+			vq->signalled_used = vq->last_used_idx;
+			eventfd_write(vq->callfd, (eventfd_t) 1);
+		}
+	} else {
+		/* Kick the guest if necessary. */
+		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+			&& (vq->callfd >= 0))
+			eventfd_write(vq->callfd, (eventfd_t)1);
+	}
+}
+
 static bool
 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
 {
@@ -410,11 +439,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 
 	/* flush used->idx update before we read avail->flags. */
 	rte_mb();
-
-	/* Kick the guest if necessary. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	vhost_notify(dev, vq);
 out:
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 		vhost_user_iotlb_rd_unlock(vq);
@@ -704,11 +729,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 
 		/* flush used->idx update before we read avail->flags. */
 		rte_mb();
-
-		/* Kick the guest if necessary. */
-		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-				&& (vq->callfd >= 0))
-			eventfd_write(vq->callfd, (eventfd_t)1);
+		vhost_notify(dev, vq);
 	}
 
 out:
@@ -1106,11 +1127,7 @@ update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	vq->used->idx += count;
 	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 			sizeof(vq->used->idx));
-
-	/* Kick guest if required. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	vhost_notify(dev, vq);
 }
 
 static __rte_always_inline struct zcopy_mbuf *
-- 
2.0.1

Re: [PATCH v5] vhost: support virtqueue interrupt/notification suppression

[Wang, Xiao W]

Hi,

> -----Original Message-----
> From: Chen, Junjie J
> Sent: Sunday, December 24, 2017 12:56 AM
> To: yliu@fridaylinux.org; maxime.coquelin@redhat.com; Bie, Tiwei
> <tiwei.bie@intel.com>; Wang, Xiao W <xiao.w.wang@intel.com>
> Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> Subject: [PATCH v5] vhost: support virtqueue interrupt/notification
> suppression
> 
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
> 
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ringin the same way the driver manipulates flags or used_event in
> available ring.
> 
> This patch is to enable this feature in vhost.
> 
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> 
[...]
> +	/* Last used index we notify to front end. */
> +	uint16_t		signalled_used;
>  #define VIRTIO_INVALID_EVENTFD		(-1)
>  #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
> 
> @@ -211,6 +213,7 @@ struct vhost_msg {
>  				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
>  				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
>  				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
> +				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
>  				(1ULL << VIRTIO_NET_F_MTU) | \
>  				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
> 
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 6fee16e..2badeda 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -52,6 +52,35 @@
> 
>  #define MAX_BATCH_LEN 256
> 
> +#define vhost_used_event(vr)  ((vr)->avail->ring[(vr)->size])
> +#define vhost_avail_event(vr) \
> +	(*(volatile uint16_t *)&(vr)->used->ring[(vr)->size])
> +

>From vhost side, vhost_used_event(vr) is volatile.

BRs,
Xiao

[PATCH v6] vhost: support virtqueue interrupt/notification suppression

[Junjie Chen]

The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
negotiated. The driver set vring flags to 0, and MAY use used_event in
available ring to advise device interrupt util reach an index specified
by used_event. The device ignore the lower bit of vring flags, and send
an interrupt when index reach used_event.

The device can suppress notification in a manner analogous to the ways
driver suppress interrupt. The device manipulates flags or avail_event in
the used ring in the same way the driver manipulates flags or used_event in
available ring.

This patch is to enable this feature in vhost.

Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>

v6: 
Use volatile qualifier to access avail event idx.

v5:
Remove updating avail event index in backend.

v2-v4:
Use definition of VIRTIO_F_EVENT_IDX from kernel.

---
 lib/librte_vhost/vhost.h      |  3 +++
 lib/librte_vhost/virtio_net.c | 46 +++++++++++++++++++++++++++++--------------
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 1cc81c1..fc41c20 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -103,6 +103,8 @@ struct vhost_virtqueue {
 
 	uint16_t		last_avail_idx;
 	uint16_t		last_used_idx;
+	/* Last used index we notify to front end. */
+	uint16_t		signalled_used;
 #define VIRTIO_INVALID_EVENTFD		(-1)
 #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
 
@@ -211,6 +213,7 @@ struct vhost_msg {
 				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
 				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
+				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
 				(1ULL << VIRTIO_NET_F_MTU) | \
 				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
 
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6fee16e..f5777fc 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -52,6 +52,34 @@
 
 #define MAX_BATCH_LEN 256
 
+#define vhost_used_event(vr) \
+	(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
+
+static __rte_always_inline void
+vhost_notify(struct virtio_net *dev,  struct vhost_virtqueue *vq)
+{
+	/* Don't notify guest if we don't reach index specified by guest. */
+	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
+		uint16_t old = vq->signalled_used;
+		uint16_t new = vq->last_used_idx;
+
+		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
+			__func__,
+			vhost_used_event(vq),
+			old, new);
+		if (vring_need_event(vhost_used_event(vq), new, old)
+			&& (vq->callfd >= 0)) {
+			vq->signalled_used = vq->last_used_idx;
+			eventfd_write(vq->callfd, (eventfd_t) 1);
+		}
+	} else {
+		/* Kick the guest if necessary. */
+		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+			&& (vq->callfd >= 0))
+			eventfd_write(vq->callfd, (eventfd_t)1);
+	}
+}
+
 static bool
 is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
 {
@@ -410,11 +438,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 
 	/* flush used->idx update before we read avail->flags. */
 	rte_mb();
-
-	/* Kick the guest if necessary. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	vhost_notify(dev, vq);
 out:
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 		vhost_user_iotlb_rd_unlock(vq);
@@ -704,11 +728,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 
 		/* flush used->idx update before we read avail->flags. */
 		rte_mb();
-
-		/* Kick the guest if necessary. */
-		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-				&& (vq->callfd >= 0))
-			eventfd_write(vq->callfd, (eventfd_t)1);
+		vhost_notify(dev, vq);
 	}
 
 out:
@@ -1106,11 +1126,7 @@ update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	vq->used->idx += count;
 	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 			sizeof(vq->used->idx));
-
-	/* Kick guest if required. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	vhost_notify(dev, vq);
 }
 
 static __rte_always_inline struct zcopy_mbuf *
-- 
2.0.1

Re: [PATCH v6] vhost: support virtqueue interrupt/notification suppression

[Wang, Xiao W]

Hi,

> -----Original Message-----
> From: Chen, Junjie J
> Sent: Wednesday, December 27, 2017 1:43 AM
> To: Wang, Xiao W <xiao.w.wang@intel.com>; yliu@fridaylinux.org;
> maxime.coquelin@redhat.com; Bie, Tiwei <tiwei.bie@intel.com>
> Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> Subject: [PATCH v6] vhost: support virtqueue interrupt/notification
> suppression
> 
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
> 
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
> 
> This patch is to enable this feature in vhost.
> 
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> 
> v6:
> Use volatile qualifier to access avail event idx.
> 
> v5:
> Remove updating avail event index in backend.
> 
> v2-v4:
> Use definition of VIRTIO_F_EVENT_IDX from kernel.
> 
> ---
>  lib/librte_vhost/vhost.h      |  3 +++
>  lib/librte_vhost/virtio_net.c | 46 +++++++++++++++++++++++++++++-------------
> -
>  2 files changed, 34 insertions(+), 15 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 1cc81c1..fc41c20 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -103,6 +103,8 @@ struct vhost_virtqueue {
> 
>  	uint16_t		last_avail_idx;
>  	uint16_t		last_used_idx;
> +	/* Last used index we notify to front end. */
> +	uint16_t		signalled_used;
>  #define VIRTIO_INVALID_EVENTFD		(-1)
>  #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
> 
> @@ -211,6 +213,7 @@ struct vhost_msg {
>  				(1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
>  				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
>  				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
> +				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
>  				(1ULL << VIRTIO_NET_F_MTU) | \
>  				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
> 
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 6fee16e..f5777fc 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -52,6 +52,34 @@
> 
>  #define MAX_BATCH_LEN 256
> 
> +#define vhost_used_event(vr) \
> +	(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> +
> +static __rte_always_inline void
> +vhost_notify(struct virtio_net *dev,  struct vhost_virtqueue *vq)
> +{
> +	/* Don't notify guest if we don't reach index specified by guest. */
> +	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> +		uint16_t old = vq->signalled_used;
> +		uint16_t new = vq->last_used_idx;
> +
> +		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d,
> new=%d\n",
> +			__func__,
> +			vhost_used_event(vq),
> +			old, new);
> +		if (vring_need_event(vhost_used_event(vq), new, old)
> +			&& (vq->callfd >= 0)) {
> +			vq->signalled_used = vq->last_used_idx;
> +			eventfd_write(vq->callfd, (eventfd_t) 1);
> +		}
> +	} else {
> +		/* Kick the guest if necessary. */
> +		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> +			&& (vq->callfd >= 0))
> +			eventfd_write(vq->callfd, (eventfd_t)1);
> +	}
> +}
> +
>  static bool
>  is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
>  {
> @@ -410,11 +438,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t
> queue_id,
> 
>  	/* flush used->idx update before we read avail->flags. */
>  	rte_mb();
> -
> -	/* Kick the guest if necessary. */
> -	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> -			&& (vq->callfd >= 0))
> -		eventfd_write(vq->callfd, (eventfd_t)1);
> +	vhost_notify(dev, vq);
>  out:
>  	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>  		vhost_user_iotlb_rd_unlock(vq);
> @@ -704,11 +728,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t
> queue_id,
> 
>  		/* flush used->idx update before we read avail->flags. */
>  		rte_mb();
> -
> -		/* Kick the guest if necessary. */
> -		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> -				&& (vq->callfd >= 0))
> -			eventfd_write(vq->callfd, (eventfd_t)1);
> +		vhost_notify(dev, vq);
>  	}
> 
>  out:
> @@ -1106,11 +1126,7 @@ update_used_idx(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	vq->used->idx += count;
>  	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
>  			sizeof(vq->used->idx));
> -
> -	/* Kick guest if required. */
> -	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> -			&& (vq->callfd >= 0))
> -		eventfd_write(vq->callfd, (eventfd_t)1);
> +	vhost_notify(dev, vq);
>  }
> 
>  static __rte_always_inline struct zcopy_mbuf *
> --
> 2.0.1

Reviewed-by: Xiao Wang <xiao.w.wang@intel.com>

Re: [PATCH v6] vhost: support virtqueue interrupt/notification suppression

[Yuanhan Liu]

On Tue, Dec 26, 2017 at 12:43:10PM -0500, Junjie Chen wrote:
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
> 
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
> 
> This patch is to enable this feature in vhost.
> 
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>

You need put "---" before the change log. Otherwise, it will be tracked in
the commit log.

> +#define vhost_used_event(vr) \
> +	(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> +
> +static __rte_always_inline void
> +vhost_notify(struct virtio_net *dev,  struct vhost_virtqueue *vq)
> +{
> +	/* Don't notify guest if we don't reach index specified by guest. */
> +	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> +		uint16_t old = vq->signalled_used;
> +		uint16_t new = vq->last_used_idx;
> +
> +		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
> +			__func__,
> +			vhost_used_event(vq),
> +			old, new);
> +		if (vring_need_event(vhost_used_event(vq), new, old)

It's a bit weird that you use one from the standard linux header file
(vring_need_event), while you define you own one (vhost_used_event).
Note that the system header file also has "vring_used_event()" defined.

Besides that, I have few more comments (and some requirements):

- It'd be much better if there is a Tested-by tag. Expeclitly,
  I'm asking a test with Linux kernel virtio-net driver in guest.

- I also hope you could have done a build test on some old distributions.
  AFAIK, the two macros (vring_need_event and vring_used_event) come
  from kernel 3.0 (or above). Any kernel older than that would fail
  the build.

- I'd be great if you could make a new one based on top of my latest
  tree: I have just applied a patchset that should conflict with this
  one.

	--yliu

Re: [PATCH v6] vhost: support virtqueue interrupt/notification suppression

[Chen, Junjie J]

Hi

> -----Original Message-----
> From: Yuanhan Liu [mailto:yliu@fridaylinux.org]
> Sent: Monday, January 8, 2018 10:07 PM
> To: Chen, Junjie J <junjie.j.chen@intel.com>
> Cc: Wang, Xiao W <xiao.w.wang@intel.com>; maxime.coquelin@redhat.com;
> Bie, Tiwei <tiwei.bie@intel.com>; dev@dpdk.org; Yao, Lei A
> <lei.a.yao@intel.com>
> Subject: Re: [PATCH v6] vhost: support virtqueue interrupt/notification
> suppression
> 
> On Tue, Dec 26, 2017 at 12:43:10PM -0500, Junjie Chen wrote:
> > The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit
> > is negotiated. The driver set vring flags to 0, and MAY use used_event
> > in available ring to advise device interrupt util reach an index
> > specified by used_event. The device ignore the lower bit of vring
> > flags, and send an interrupt when index reach used_event.
> >
> > The device can suppress notification in a manner analogous to the ways
> > driver suppress interrupt. The device manipulates flags or avail_event
> > in the used ring in the same way the driver manipulates flags or
> > used_event in available ring.
> >
> > This patch is to enable this feature in vhost.
> >
> > Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> 
> You need put "---" before the change log. Otherwise, it will be tracked in the
> commit log.

Will update this.
> 
> > +#define vhost_used_event(vr) \
> > +	(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> > +
> > +static __rte_always_inline void
> > +vhost_notify(struct virtio_net *dev,  struct vhost_virtqueue *vq) {
> > +	/* Don't notify guest if we don't reach index specified by guest. */
> > +	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> > +		uint16_t old = vq->signalled_used;
> > +		uint16_t new = vq->last_used_idx;
> > +
> > +		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d,
> new=%d\n",
> > +			__func__,
> > +			vhost_used_event(vq),
> > +			old, new);
> > +		if (vring_need_event(vhost_used_event(vq), new, old)
> 
> It's a bit weird that you use one from the standard linux header file
> (vring_need_event), while you define you own one (vhost_used_event).
> Note that the system header file also has "vring_used_event()" defined.
The vring_used_event is defined and used for virtio in kernel, kernel defines a vhost_used_event in vhost.c for vhost, so I just use a separated macro for vhost end.

I'd like to define both vhost_need_event and vhost_used_event in vhost.h to remove potential build issue in old linux distribution and also to keep consistent. Is that OK for you?

> 
> Besides that, I have few more comments (and some requirements):
> 
> - It'd be much better if there is a Tested-by tag. Expeclitly,
>   I'm asking a test with Linux kernel virtio-net driver in guest.
Sure.
> 
> - I also hope you could have done a build test on some old distributions.
>   AFAIK, the two macros (vring_need_event and vring_used_event) come
>   from kernel 3.0 (or above). Any kernel older than that would fail
>   the build.
> 
> - I'd be great if you could make a new one based on top of my latest
>   tree: I have just applied a patchset that should conflict with this
>   one.

Sure, will do this.
> 
> 	--yliu

Re: [PATCH v6] vhost: support virtqueue interrupt/notification suppression

[Yuanhan Liu]

On Tue, Jan 09, 2018 at 02:12:02AM +0000, Chen, Junjie J wrote:
> > > +		if (vring_need_event(vhost_used_event(vq), new, old)
> > 
> > It's a bit weird that you use one from the standard linux header file
> > (vring_need_event), while you define you own one (vhost_used_event).
> > Note that the system header file also has "vring_used_event()" defined.
> The vring_used_event is defined and used for virtio in kernel, kernel defines a vhost_used_event in vhost.c for vhost, so I just use a separated macro for vhost end.
> 
> I'd like to define both vhost_need_event and vhost_used_event in vhost.h to remove potential build issue in old linux distribution and also to keep consistent. Is that OK for you?

Yes.

	--yliu

Re: [PATCH v7] vhost: support virtqueue interrupt/notification suppression

[Yao, Lei A]

> -----Original Message-----
> From: Chen, Junjie J
> Sent: Tuesday, January 9, 2018 7:04 PM
> To: yliu@fridaylinux.org; maxime.coquelin@redhat.com; Wang, Xiao W
> <xiao.w.wang@intel.com>; Bie, Tiwei <tiwei.bie@intel.com>; Yao, Lei A
> <lei.a.yao@intel.com>
> Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> Subject: [PATCH v7] vhost: support virtqueue interrupt/notification
> suppression
> 
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
> 
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
> 
> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
Tested-by: Lei Yao <lei.a.yao@intel.com>
VM2VM Iperf test has been executed with virtio-net driver after apply this patch.
No performance drop. 
CPU: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
Host OS: Ubuntu 16.04
Guest OS: Ubuntu 16.04
Kernel: 4.4.0
> ---
> v7:
> Add vhost_need_event definition and update code for next virtio.
> 
> v6:
> Use volatile qualifier to access avail event idx.
> 
> v5:
> Remove updating avail event index in backend.
> 
> v2-v4:
> Use definition of VIRTIO_F_EVENT_IDX from kernel.
> 
>  lib/librte_vhost/vhost.c      |  2 +-
>  lib/librte_vhost/vhost.h      | 44
> ++++++++++++++++++++++++++++++++++++++-----
>  lib/librte_vhost/virtio_net.c |  6 +++---
>  3 files changed, 43 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index 6f7ef7f..400caa0 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -538,7 +538,7 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
>  	if (!vq)
>  		return -1;
> 
> -	vhost_vring_call(vq);
> +	vhost_vring_call(dev, vq);
>  	return 0;
>  }
> 
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 1d9366e..ec79991 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -103,6 +103,8 @@ struct vhost_virtqueue {
> 
>  	uint16_t		last_avail_idx;
>  	uint16_t		last_used_idx;
> +	/* Last used index we notify to front end. */
> +	uint16_t		signalled_used;
>  #define VIRTIO_INVALID_EVENTFD		(-1)
>  #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
> 
> @@ -214,6 +216,7 @@ struct vhost_msg {
>  				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
>  				(1ULL << VIRTIO_NET_F_GUEST_UFO) | \
>  				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> \
> +				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
>  				(1ULL << VIRTIO_NET_F_MTU) | \
>  				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
> 
> @@ -399,16 +402,47 @@ vhost_iova_to_vva(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	return __vhost_iova_to_vva(dev, vq, iova, size, perm);
>  }
> 
> +#define vhost_used_event(vr) \
> +	(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> +
> +/*
> + * The following is used with VIRTIO_RING_F_EVENT_IDX.
> + * Assuming a given event_idx value from the other size, if we have
> + * just incremented index from old to new_idx, should we trigger an
> + * event?
> + */
> +static __rte_always_inline int
> +vhost_need_event(uint16_t event_idx, uint16_t new_idx, uint16_t old)
> +{
> +	return (uint16_t)(new_idx - event_idx - 1) < (uint16_t)(new_idx -
> old);
> +}
> +
>  static __rte_always_inline void
> -vhost_vring_call(struct vhost_virtqueue *vq)
> +vhost_vring_call(struct virtio_net *dev, struct vhost_virtqueue *vq)
>  {
>  	/* Flush used->idx update before we read avail->flags. */
>  	rte_mb();
> 
> -	/* Kick the guest if necessary. */
> -	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> -			&& (vq->callfd >= 0))
> -		eventfd_write(vq->callfd, (eventfd_t)1);
> +	/* Don't kick guest if we don't reach index specified by guest. */
> +	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> +		uint16_t old = vq->signalled_used;
> +		uint16_t new = vq->last_used_idx;
> +
> +		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d,
> old=%d, new=%d\n",
> +			__func__,
> +			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;
> +			eventfd_write(vq->callfd, (eventfd_t) 1);
> +		}
> +	} else {
> +		/* Kick the guest if necessary. */
> +		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
> +				&& (vq->callfd >= 0))
> +			eventfd_write(vq->callfd, (eventfd_t)1);
> +	}
>  }
> 
>  #endif /* _VHOST_NET_CDEV_H_ */
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index eb496e1..d0f9221 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -413,7 +413,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t
> queue_id,
>  		offsetof(struct vring_used, idx),
>  		sizeof(vq->used->idx));
> 
> -	vhost_vring_call(vq);
> +	vhost_vring_call(dev, vq);
>  out:
>  	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>  		vhost_user_iotlb_rd_unlock(vq);
> @@ -700,7 +700,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t
> queue_id,
> 
>  	if (likely(vq->shadow_used_idx)) {
>  		flush_shadow_used_ring(dev, vq);
> -		vhost_vring_call(vq);
> +		vhost_vring_call(dev, vq);
>  	}
> 
>  out:
> @@ -1104,7 +1104,7 @@ update_used_idx(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	vq->used->idx += count;
>  	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
>  			sizeof(vq->used->idx));
> -	vhost_vring_call(vq);
> +	vhost_vring_call(dev, vq);
>  }
> 
>  static __rte_always_inline struct zcopy_mbuf *
> --
> 2.0.1

Re: [PATCH v7] vhost: support virtqueue interrupt/notification suppression

[Maxime Coquelin]

On 01/09/2018 12:03 PM, Junjie Chen wrote:
> The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> negotiated. The driver set vring flags to 0, and MAY use used_event in
> available ring to advise device interrupt util reach an index specified
> by used_event. The device ignore the lower bit of vring flags, and send
> an interrupt when index reach used_event.
> 
> The device can suppress notification in a manner analogous to the ways
> driver suppress interrupt. The device manipulates flags or avail_event in
> the used ring in the same way the driver manipulates flags or used_event in
> available ring.
> 
> Signed-off-by: Junjie Chen<junjie.j.chen@intel.com>
> ---
> v7:
> Add vhost_need_event definition and update code for next virtio.
> 
> v6:
> Use volatile qualifier to access avail event idx.
> 
> v5:
> Remove updating avail event index in backend.
> 
> v2-v4:
> Use definition of VIRTIO_F_EVENT_IDX from kernel.
> 
>   lib/librte_vhost/vhost.c      |  2 +-
>   lib/librte_vhost/vhost.h      | 44 ++++++++++++++++++++++++++++++++++++++-----
>   lib/librte_vhost/virtio_net.c |  6 +++---
>   3 files changed, 43 insertions(+), 9 deletions(-)

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

[PATCH v7] vhost: support virtqueue interrupt/notification suppression

[Junjie Chen]

The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
negotiated. The driver set vring flags to 0, and MAY use used_event in
available ring to advise device interrupt util reach an index specified
by used_event. The device ignore the lower bit of vring flags, and send
an interrupt when index reach used_event.

The device can suppress notification in a manner analogous to the ways
driver suppress interrupt. The device manipulates flags or avail_event in
the used ring in the same way the driver manipulates flags or used_event in
available ring.

Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
---
v7:
Add vhost_need_event definition and update code for next virtio.

v6: 
Use volatile qualifier to access avail event idx.

v5:
Remove updating avail event index in backend.

v2-v4:
Use definition of VIRTIO_F_EVENT_IDX from kernel.

 lib/librte_vhost/vhost.c      |  2 +-
 lib/librte_vhost/vhost.h      | 44 ++++++++++++++++++++++++++++++++++++++-----
 lib/librte_vhost/virtio_net.c |  6 +++---
 3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 6f7ef7f..400caa0 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -538,7 +538,7 @@ rte_vhost_vring_call(int vid, uint16_t vring_idx)
 	if (!vq)
 		return -1;
 
-	vhost_vring_call(vq);
+	vhost_vring_call(dev, vq);
 	return 0;
 }
 
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 1d9366e..ec79991 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -103,6 +103,8 @@ struct vhost_virtqueue {
 
 	uint16_t		last_avail_idx;
 	uint16_t		last_used_idx;
+	/* Last used index we notify to front end. */
+	uint16_t		signalled_used;
 #define VIRTIO_INVALID_EVENTFD		(-1)
 #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
 
@@ -214,6 +216,7 @@ struct vhost_msg {
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
 				(1ULL << VIRTIO_NET_F_GUEST_UFO) | \
 				(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
+				(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
 				(1ULL << VIRTIO_NET_F_MTU) | \
 				(1ULL << VIRTIO_F_IOMMU_PLATFORM))
 
@@ -399,16 +402,47 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	return __vhost_iova_to_vva(dev, vq, iova, size, perm);
 }
 
+#define vhost_used_event(vr) \
+	(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
+
+/*
+ * The following is used with VIRTIO_RING_F_EVENT_IDX.
+ * Assuming a given event_idx value from the other size, if we have
+ * just incremented index from old to new_idx, should we trigger an
+ * event?
+ */
+static __rte_always_inline int
+vhost_need_event(uint16_t event_idx, uint16_t new_idx, uint16_t old)
+{
+	return (uint16_t)(new_idx - event_idx - 1) < (uint16_t)(new_idx - old);
+}
+
 static __rte_always_inline void
-vhost_vring_call(struct vhost_virtqueue *vq)
+vhost_vring_call(struct virtio_net *dev, struct vhost_virtqueue *vq)
 {
 	/* Flush used->idx update before we read avail->flags. */
 	rte_mb();
 
-	/* Kick the guest if necessary. */
-	if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
-			&& (vq->callfd >= 0))
-		eventfd_write(vq->callfd, (eventfd_t)1);
+	/* Don't kick guest if we don't reach index specified by guest. */
+	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
+		uint16_t old = vq->signalled_used;
+		uint16_t new = vq->last_used_idx;
+
+		LOG_DEBUG(VHOST_DATA, "%s: used_event_idx=%d, old=%d, new=%d\n",
+			__func__,
+			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;
+			eventfd_write(vq->callfd, (eventfd_t) 1);
+		}
+	} else {
+		/* Kick the guest if necessary. */
+		if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+				&& (vq->callfd >= 0))
+			eventfd_write(vq->callfd, (eventfd_t)1);
+	}
 }
 
 #endif /* _VHOST_NET_CDEV_H_ */
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index eb496e1..d0f9221 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -413,7 +413,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 		offsetof(struct vring_used, idx),
 		sizeof(vq->used->idx));
 
-	vhost_vring_call(vq);
+	vhost_vring_call(dev, vq);
 out:
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 		vhost_user_iotlb_rd_unlock(vq);
@@ -700,7 +700,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
 
 	if (likely(vq->shadow_used_idx)) {
 		flush_shadow_used_ring(dev, vq);
-		vhost_vring_call(vq);
+		vhost_vring_call(dev, vq);
 	}
 
 out:
@@ -1104,7 +1104,7 @@ update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	vq->used->idx += count;
 	vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
 			sizeof(vq->used->idx));
-	vhost_vring_call(vq);
+	vhost_vring_call(dev, vq);
 }
 
 static __rte_always_inline struct zcopy_mbuf *
-- 
2.0.1

Re: [PATCH v7] vhost: support virtqueue interrupt/notification suppression

[Yuanhan Liu]

On Tue, Jan 09, 2018 at 07:34:17AM +0000, Yao, Lei A wrote:
> 
> 
> > -----Original Message-----
> > From: Chen, Junjie J
> > Sent: Tuesday, January 9, 2018 7:04 PM
> > To: yliu@fridaylinux.org; maxime.coquelin@redhat.com; Wang, Xiao W
> > <xiao.w.wang@intel.com>; Bie, Tiwei <tiwei.bie@intel.com>; Yao, Lei A
> > <lei.a.yao@intel.com>
> > Cc: dev@dpdk.org; Chen, Junjie J <junjie.j.chen@intel.com>
> > Subject: [PATCH v7] vhost: support virtqueue interrupt/notification
> > suppression
> > 
> > The driver can suppress interrupt when VIRTIO_F_EVENT_IDX feature bit is
> > negotiated. The driver set vring flags to 0, and MAY use used_event in
> > available ring to advise device interrupt util reach an index specified
> > by used_event. The device ignore the lower bit of vring flags, and send
> > an interrupt when index reach used_event.
> > 
> > The device can suppress notification in a manner analogous to the ways
> > driver suppress interrupt. The device manipulates flags or avail_event in
> > the used ring in the same way the driver manipulates flags or used_event in
> > available ring.
> > 
> > Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> Tested-by: Lei Yao <lei.a.yao@intel.com>

Applied to dpdk-next-virtio.

Thanks.

	--yliu

> VM2VM Iperf test has been executed with virtio-net driver after apply this patch.
> No performance drop. 
> CPU: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
> Host OS: Ubuntu 16.04
> Guest OS: Ubuntu 16.04
> Kernel: 4.4.0