From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by dpdk.org (Postfix) with ESMTP id 140041041; Mon, 10 Sep 2018 09:37:38 +0200 (CEST) X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Sep 2018 00:37:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,355,1531810800"; d="scan'208";a="82228037" Received: from btwcube1.sh.intel.com (HELO debian) ([10.67.104.194]) by orsmga003.jf.intel.com with ESMTP; 10 Sep 2018 00:37:36 -0700 Date: Mon, 10 Sep 2018 15:36:37 +0800 From: Tiwei Bie To: Maxime Coquelin Cc: zhihong.wang@intel.com, dev@dpdk.org, stable@dpdk.org Message-ID: <20180910073637.GA25254@debian> References: <20180904235555.31839-1-tiwei.bie@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [dpdk-dev] [PATCH] vhost: fix vhost interrupt support 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: Mon, 10 Sep 2018 07:37:40 -0000 Hi Maxime, On Mon, Sep 10, 2018 at 09:22:00AM +0200, Maxime Coquelin wrote: > Hi Tiwei, > > On 09/05/2018 01:55 AM, Tiwei Bie wrote: > > When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to > > update the avail event to enable the notification. > > > > Fixes: 3f8ff12821e4 ("vhost: support interrupt mode") > > Cc: stable@dpdk.org > > > > Signed-off-by: Tiwei Bie > > --- > > lib/librte_vhost/Makefile | 1 + > > lib/librte_vhost/vhost.c | 18 ++++++++++++------ > > lib/librte_vhost/vhost.h | 2 ++ > > 3 files changed, 15 insertions(+), 6 deletions(-) > > > > diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile > > index de431fbb7..531cf4832 100644 > > --- a/lib/librte_vhost/Makefile > > +++ b/lib/librte_vhost/Makefile > > @@ -13,6 +13,7 @@ LIBABIVER := 4 > > CFLAGS += -DALLOW_EXPERIMENTAL_API > > CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64 > > CFLAGS += -I vhost_user > > +CFLAGS += -fno-strict-aliasing > > I'm not clear why this is needed looking at the code below, > could you please explain? Without this, we will get below build error: lib/librte_vhost/vhost.c: In function ‘vhost_enable_notify_split’: lib/librte_vhost/vhost.h:656:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size]) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/librte_vhost/vhost.c:659:4: note: in expansion of macro ‘vhost_avail_event’ vhost_avail_event(vq) = vq->last_avail_idx; ^~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors > > > LDLIBS += -lpthread > > ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y) > > diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c > > index 3c9be10a0..88b1781d5 100644 > > --- a/lib/librte_vhost/vhost.c > > +++ b/lib/librte_vhost/vhost.c > > @@ -646,12 +646,18 @@ rte_vhost_avail_entries(int vid, uint16_t queue_id) > > } > > static inline void > > -vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable) > > +vhost_enable_notify_split(struct virtio_net *dev, > > + struct vhost_virtqueue *vq, int enable) > > { > > - if (enable) > > - vq->used->flags &= ~VRING_USED_F_NO_NOTIFY; > > - else > > - vq->used->flags |= VRING_USED_F_NO_NOTIFY; > > + if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) { > > + if (enable) > > + vq->used->flags &= ~VRING_USED_F_NO_NOTIFY; > > + else > > + vq->used->flags |= VRING_USED_F_NO_NOTIFY; > > + } else { > > + if (enable) > > + vhost_avail_event(vq) = vq->last_avail_idx; > > + } > > } > > static inline void > > @@ -689,7 +695,7 @@ rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable) > > if (vq_is_packed(dev)) > > vhost_enable_notify_packed(dev, vq, enable); > > else > > - vhost_enable_notify_split(vq, enable); > > + vhost_enable_notify_split(dev, vq, enable); > > return 0; > > } > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > > index 760a09c0d..25ffd7614 100644 > > --- a/lib/librte_vhost/vhost.h > > +++ b/lib/librte_vhost/vhost.h > > @@ -648,6 +648,8 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq, > > return __vhost_iova_to_vva(dev, vq, iova, len, perm); > > } > > +#define vhost_avail_event(vr) \ > > + (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size]) > > #define vhost_used_event(vr) \ > > (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size]) > >