From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 751CD1B025 for ; Tue, 9 Jan 2018 04:23:24 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jan 2018 19:23:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,334,1511856000"; d="scan'208";a="22494361" Received: from dpdk-dev.sh.intel.com ([10.67.111.147]) by orsmga001.jf.intel.com with ESMTP; 08 Jan 2018 19:23:21 -0800 From: Junjie Chen To: yliu@fridaylinux.org, maxime.coquelin@redhat.com, xiao.w.wang@intel.com, tiwei.bie@intel.com, lei.a.yao@intel.com Cc: dev@dpdk.org, Junjie Chen Date: Tue, 9 Jan 2018 06:03:48 -0500 Message-Id: <1515495828-190409-1-git-send-email-junjie.j.chen@intel.com> X-Mailer: git-send-email 2.0.1 In-Reply-To: <1514310190-140916-1-git-send-email-junjie.j.chen@intel.com> References: <1514310190-140916-1-git-send-email-junjie.j.chen@intel.com> Subject: [dpdk-dev] [PATCH v7] vhost: support virtqueue interrupt/notification suppression X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Jan 2018 03:23:25 -0000 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 --- 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