* Re: [dpdk-dev] [PATCH v2] vhost: support virtqueue interrupt/notification suppression
2017-11-28 9:48 [dpdk-dev] [PATCH v2] vhost: support virtqueue interrupt/notification suppression junjie.j.chen
@ 2017-11-28 2:46 ` Tiwei Bie
0 siblings, 0 replies; 2+ messages in thread
From: Tiwei Bie @ 2017-11-28 2:46 UTC (permalink / raw)
To: junjie.j.chen; +Cc: yliu, maxime.coquelin, jianfeng.tan, dev
Hi,
On Tue, Nov 28, 2017 at 04:48:26AM -0500, junjie.j.chen@intel.com wrote:
[...]
> @@ -195,6 +197,10 @@ struct vhost_msg {
>
> #define VHOST_USER_F_PROTOCOL_FEATURES 30
>
> +#ifndef VIRTIO_F_EVENT_IDX
> + #define VIRTIO_F_EVENT_IDX 29
> +#endif
> +
> /* Features supported by this builtin vhost-user net driver. */
> #define VIRTIO_NET_SUPPORTED_FEATURES ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | \
> (1ULL << VIRTIO_NET_F_CTRL_VQ) | \
> @@ -212,7 +218,8 @@ struct vhost_msg {
> (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
> (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
> (1ULL << VIRTIO_NET_F_MTU) | \
> - (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> + (1ULL << VIRTIO_F_IOMMU_PLATFORM) | \
> + (1ULL << VIRTIO_F_EVENT_IDX))
>
You can use VIRTIO_RING_F_EVENT_IDX directly. It has already
been defined by Linux. And you can add this new feature bit
after VIRTIO_RING_F_INDIRECT_DESC:
diff --git i/lib/librte_vhost/vhost.h w/lib/librte_vhost/vhost.h
index 2f36a034e..350ac3acc 100644
--- i/lib/librte_vhost/vhost.h
+++ w/lib/librte_vhost/vhost.h
@@ -211,6 +211,7 @@ 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))
Best regards,
Tiwei
^ permalink raw reply [flat|nested] 2+ messages in thread
* [dpdk-dev] [PATCH v2] vhost: support virtqueue interrupt/notification suppression
@ 2017-11-28 9:48 junjie.j.chen
2017-11-28 2:46 ` Tiwei Bie
0 siblings, 1 reply; 2+ messages in thread
From: junjie.j.chen @ 2017-11-28 9:48 UTC (permalink / raw)
To: yliu, maxime.coquelin, tiwei.bie, jianfeng.tan, dev; +Cc: Junjie 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 | 9 ++++++-
lib/librte_vhost/virtio_net.c | 56 +++++++++++++++++++++++++++++++------------
3 files changed, 50 insertions(+), 16 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..b0a955f64 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)
@@ -195,6 +197,10 @@ struct vhost_msg {
#define VHOST_USER_F_PROTOCOL_FEATURES 30
+#ifndef VIRTIO_F_EVENT_IDX
+ #define VIRTIO_F_EVENT_IDX 29
+#endif
+
/* Features supported by this builtin vhost-user net driver. */
#define VIRTIO_NET_SUPPORTED_FEATURES ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | \
(1ULL << VIRTIO_NET_F_CTRL_VQ) | \
@@ -212,7 +218,8 @@ struct vhost_msg {
(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
(1ULL << VIRTIO_NET_F_MTU) | \
- (1ULL << VIRTIO_F_IOMMU_PLATFORM))
+ (1ULL << VIRTIO_F_IOMMU_PLATFORM) | \
+ (1ULL << VIRTIO_F_EVENT_IDX))
struct guest_page {
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6fee16e55..0c1d66d7c 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_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_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
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-11-28 9:48 [dpdk-dev] [PATCH v2] vhost: support virtqueue interrupt/notification suppression junjie.j.chen
2017-11-28 2:46 ` Tiwei Bie
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