From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by dpdk.org (Postfix) with ESMTP id DE1B81B314; Fri, 19 Jan 2018 14:51:46 +0100 (CET) Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 4764220ADA; Fri, 19 Jan 2018 08:51:46 -0500 (EST) Received: from frontend1 ([10.202.2.160]) by compute1.internal (MEProxy); Fri, 19 Jan 2018 08:51:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fridaylinux.org; h=cc:content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to:x-me-sender:x-me-sender:x-sasl-enc; s= fm1; bh=Eba/beRJXALq7vTA8KPYBaeP2sGhbPmJUFdaOfhrVPc=; b=td1DjLzv oQTlVDYnn++KsE+oWRBTseNPIjGMrZttWk8s/qh8Ic/jN0jGy6W9YO9w+v6IVp7N yjUVuPmo6WT2XJztev2qdvgM3O7ofYCmi3Zw7XvgRXNsb68IcezLQ/8wNcmjNL10 REfQaO9I9cz9vKrwo5Qnb+XPZQPsPmMUe7HTa7FZtn8f/Jz5ka9lKdcbTjB0hcAI +5yhry/c5I+F3tEc7b5n/4aJ4IHu7K7MjErIdtks8s4p1Fil63YZx8OUjXKGtEQ2 nSlNmNPb6ajtOEnd3W0nY7uS5DBa75yfDOLZo8JHAz3U7idHOpB4KZ7OGO/z8oou xfVifWvP4qATbQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-sender :x-me-sender:x-sasl-enc; s=fm1; bh=Eba/beRJXALq7vTA8KPYBaeP2sGhb PmJUFdaOfhrVPc=; b=lWuZNyfSXXf7J0yNff/aTkqdGj4ngO02EmVGYYkcxMBOO KAhxfwAA7yaTGG7+J/HLQWTcV0fSegQJPF1/R+QEZ3CEis+GhSBrbdv56dxPAllf zpEuK7WSVEcQDkhEXvIxMmXomhO5LpZz3rPSAMYYqfm3GCv06ZO0QsN81JFXS8Et TsUn0m1hpseaaZ+UO3EATy3+KPIkwA6+AAu7K1UxLS666NYa8O3vOr7Oo8FCEqPp i5yVOWUOW4yuvoY9Qpsnj/ysrBgGnWAnvuR6F+fUeJUJQ0fUyvkVgrroTmnTO2BR G4RF6q1HR71mRPsbuL2eA81vXix/7GuoPGcMGAO2Q== X-ME-Sender: Received: from yliu-mob (unknown [115.148.90.22]) by mail.messagingengine.com (Postfix) with ESMTPA id C4D087E0FA; Fri, 19 Jan 2018 08:51:44 -0500 (EST) Date: Fri, 19 Jan 2018 21:51:40 +0800 From: Yuanhan Liu To: Victor Kaplansky Cc: dev@dpdk.org, stable@dpdk.org, Jens Freimann , Maxime Coquelin , Tiwei Bie , "Tan, Jianfeng" , Stephen Hemminger Message-ID: <20180119135140.GO29540@yliu-mob> References: <20180117154925-mutt-send-email-victork@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180117154925-mutt-send-email-victork@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) Subject: Re: [dpdk-dev] [PATCH v5] vhost_user: protect active rings from async ring changes 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: Fri, 19 Jan 2018 13:51:47 -0000 On Wed, Jan 17, 2018 at 03:49:25PM +0200, Victor Kaplansky wrote: > When performing live migration or memory hot-plugging, > the changes to the device and vrings made by message handler > done independently from vring usage by PMD threads. > > This causes for example segfaults during live-migration > with MQ enable, but in general virtually any request > sent by qemu changing the state of device can cause > problems. Applied to dpdk-next-virtio, with Cc: stable@dpdk.org Thanks. --yliu > > These patches fixes all above issues by adding a spinlock > to every vring and requiring message handler to start operation > only after ensuring that all PMD threads related to the device > are out of critical section accessing the vring data. > > Each vring has its own lock in order to not create contention > between PMD threads of different vrings and to prevent > performance degradation by scaling queue pair number. > > See https://bugzilla.redhat.com/show_bug.cgi?id=1450680 > > Signed-off-by: Victor Kaplansky > --- > v5: > o get rid of spinlock wrapping functions in vhost.h > > v4: > > o moved access_unlock before accessing enable flag and > access_unlock after iommu_unlock consistently. > o cosmetics: removed blank line. > o the access_lock variable moved to be in the same > cache line with enable and access_ok flags. > o dequeue path is now guarded with trylock and returning > zero if unsuccessful. > o GET_VRING_BASE operation is not guarded by access lock > to avoid deadlock with device_destroy. See the comment > in the code. > o Fixed error path exit from enqueue and dequeue carefully > unlocking access and iommu locks as appropriate. > > v3: > o Added locking to enqueue flow. > o Enqueue path guarded as well as dequeue path. > o Changed name of active_lock. > o Added initialization of guarding spinlock. > o Reworked functions skimming over all virt-queues. > o Performance measurements done by Maxime Coquelin shows > no degradation in bandwidth and throughput. > o Spelling. > o Taking lock only on set operations. > o IOMMU messages are not guarded by access lock. > > v2: > o Fixed checkpatch complains. > o Added Signed-off-by. > o Refined placement of guard to exclude IOMMU messages. > o TODO: performance degradation measurement. > > lib/librte_vhost/vhost.h | 6 ++-- > lib/librte_vhost/vhost.c | 1 + > lib/librte_vhost/vhost_user.c | 70 +++++++++++++++++++++++++++++++++++++++++++ > lib/librte_vhost/virtio_net.c | 28 ++++++++++++++--- > 4 files changed, 99 insertions(+), 6 deletions(-) > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > index 1cc81c17..c8f2a817 100644 > --- a/lib/librte_vhost/vhost.h > +++ b/lib/librte_vhost/vhost.h > @@ -108,12 +108,14 @@ struct vhost_virtqueue { > > /* Backend value to determine if device should started/stopped */ > int backend; > + int enabled; > + int access_ok; > + rte_spinlock_t access_lock; > + > /* Used to notify the guest (trigger interrupt) */ > int callfd; > /* Currently unused as polling mode is enabled */ > int kickfd; > - int enabled; > - int access_ok; > > /* Physical address of used ring, for logging */ > uint64_t log_guest_addr; > diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c > index 4f8b73a0..dcc42fc7 100644 > --- a/lib/librte_vhost/vhost.c > +++ b/lib/librte_vhost/vhost.c > @@ -259,6 +259,7 @@ alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx) > > dev->virtqueue[vring_idx] = vq; > init_vring_queue(dev, vring_idx); > + rte_spinlock_init(&vq->access_lock); > > dev->nr_vring += 1; > > diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c > index f4c7ce46..0685d4e7 100644 > --- a/lib/librte_vhost/vhost_user.c > +++ b/lib/librte_vhost/vhost_user.c > @@ -1190,12 +1190,47 @@ vhost_user_check_and_alloc_queue_pair(struct virtio_net *dev, VhostUserMsg *msg) > return alloc_vring_queue(dev, vring_idx); > } > > +static void > +vhost_user_lock_all_queue_pairs(struct virtio_net *dev) > +{ > + unsigned int i = 0; > + unsigned int vq_num = 0; > + > + while (vq_num < dev->nr_vring) { > + struct vhost_virtqueue *vq = dev->virtqueue[i]; > + > + if (vq) { > + rte_spinlock_lock(&vq->access_lock); > + vq_num++; > + } > + i++; > + } > +} > + > +static void > +vhost_user_unlock_all_queue_pairs(struct virtio_net *dev) > +{ > + unsigned int i = 0; > + unsigned int vq_num = 0; > + > + while (vq_num < dev->nr_vring) { > + struct vhost_virtqueue *vq = dev->virtqueue[i]; > + > + if (vq) { > + rte_spinlock_unlock(&vq->access_lock); > + vq_num++; > + } > + i++; > + } > +} > + > int > vhost_user_msg_handler(int vid, int fd) > { > struct virtio_net *dev; > struct VhostUserMsg msg; > int ret; > + int unlock_required = 0; > > dev = get_device(vid); > if (dev == NULL) > @@ -1241,6 +1276,38 @@ vhost_user_msg_handler(int vid, int fd) > return -1; > } > > + /* > + * Note: we don't lock all queues on VHOST_USER_GET_VRING_BASE, > + * since it is sent when virtio stops and device is destroyed. > + * destroy_device waits for queues to be inactive, so it is safe. > + * Otherwise taking the access_lock would cause a dead lock. > + */ > + switch (msg.request.master) { > + case VHOST_USER_SET_FEATURES: > + case VHOST_USER_SET_PROTOCOL_FEATURES: > + case VHOST_USER_SET_OWNER: > + case VHOST_USER_RESET_OWNER: > + case VHOST_USER_SET_MEM_TABLE: > + case VHOST_USER_SET_LOG_BASE: > + case VHOST_USER_SET_LOG_FD: > + case VHOST_USER_SET_VRING_NUM: > + case VHOST_USER_SET_VRING_ADDR: > + case VHOST_USER_SET_VRING_BASE: > + case VHOST_USER_SET_VRING_KICK: > + case VHOST_USER_SET_VRING_CALL: > + case VHOST_USER_SET_VRING_ERR: > + case VHOST_USER_SET_VRING_ENABLE: > + case VHOST_USER_SEND_RARP: > + case VHOST_USER_NET_SET_MTU: > + case VHOST_USER_SET_SLAVE_REQ_FD: > + vhost_user_lock_all_queue_pairs(dev); > + unlock_required = 1; > + break; > + default: > + break; > + > + } > + > switch (msg.request.master) { > case VHOST_USER_GET_FEATURES: > msg.payload.u64 = vhost_user_get_features(dev); > @@ -1342,6 +1409,9 @@ vhost_user_msg_handler(int vid, int fd) > > } > > + if (unlock_required) > + vhost_user_unlock_all_queue_pairs(dev); > + > if (msg.flags & VHOST_USER_NEED_REPLY) { > msg.payload.u64 = !!ret; > msg.size = sizeof(msg.payload.u64); > diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c > index 6fee16e5..e09a927d 100644 > --- a/lib/librte_vhost/virtio_net.c > +++ b/lib/librte_vhost/virtio_net.c > @@ -44,6 +44,7 @@ > #include > #include > #include > +#include > > #include "iotlb.h" > #include "vhost.h" > @@ -326,8 +327,11 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id, > } > > vq = dev->virtqueue[queue_id]; > + > + rte_spinlock_lock(&vq->access_lock); > + > if (unlikely(vq->enabled == 0)) > - return 0; > + goto out_access_unlock; > > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > vhost_user_iotlb_rd_lock(vq); > @@ -419,6 +423,9 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id, > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > vhost_user_iotlb_rd_unlock(vq); > > +out_access_unlock: > + rte_spinlock_unlock(&vq->access_lock); > + > return count; > } > > @@ -651,8 +658,11 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id, > } > > vq = dev->virtqueue[queue_id]; > + > + rte_spinlock_lock(&vq->access_lock); > + > if (unlikely(vq->enabled == 0)) > - return 0; > + goto out_access_unlock; > > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > vhost_user_iotlb_rd_lock(vq); > @@ -715,6 +725,9 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id, > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > vhost_user_iotlb_rd_unlock(vq); > > +out_access_unlock: > + rte_spinlock_unlock(&vq->access_lock); > + > return pkt_idx; > } > > @@ -1180,9 +1193,13 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id, > } > > vq = dev->virtqueue[queue_id]; > - if (unlikely(vq->enabled == 0)) > + > + if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0)) > return 0; > > + if (unlikely(vq->enabled == 0)) > + goto out_access_unlock; > + > vq->batch_copy_nb_elems = 0; > > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > @@ -1240,7 +1257,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id, > if (rarp_mbuf == NULL) { > RTE_LOG(ERR, VHOST_DATA, > "Failed to allocate memory for mbuf.\n"); > - return 0; > + goto out; > } > > if (make_rarp_packet(rarp_mbuf, &dev->mac)) { > @@ -1356,6 +1373,9 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id, > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > vhost_user_iotlb_rd_unlock(vq); > > +out_access_unlock: > + rte_spinlock_unlock(&vq->access_lock); > + > if (unlikely(rarp_mbuf != NULL)) { > /* > * Inject it to the head of "pkts" array, so that switch's mac > -- > Victor