From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id A86434C73 for ; Mon, 19 Mar 2018 07:56:59 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Mar 2018 23:56:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,329,1517904000"; d="scan'208";a="26440249" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by orsmga008.jf.intel.com with ESMTP; 18 Mar 2018 23:56:54 -0700 Received: from fmsmsx158.amr.corp.intel.com (10.18.116.75) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.319.2; Sun, 18 Mar 2018 23:56:54 -0700 Received: from shsmsx151.ccr.corp.intel.com (10.239.6.50) by fmsmsx158.amr.corp.intel.com (10.18.116.75) with Microsoft SMTP Server (TLS) id 14.3.319.2; Sun, 18 Mar 2018 23:56:53 -0700 Received: from shsmsx103.ccr.corp.intel.com ([169.254.4.235]) by SHSMSX151.ccr.corp.intel.com ([169.254.3.108]) with mapi id 14.03.0319.002; Mon, 19 Mar 2018 14:56:51 +0800 From: "Tan, Jianfeng" To: "Chen, Junjie J" , "maxime.coquelin@redhat.com" , "yliu@fridaylinux.org" CC: "dev@dpdk.org" Thread-Topic: [PATCH v4] doc: add driver limitation for vhost dequeue zero copy Thread-Index: AQHTu3Dvnn6qrGjju0aDvYjB8r38uqPXJ+uw Date: Mon, 19 Mar 2018 06:56:51 +0000 Message-ID: References: <1520590048-151284-1-git-send-email-junjie.j.chen@intel.com> <1521044656-105962-1-git-send-email-junjie.j.chen@intel.com> In-Reply-To: <1521044656-105962-1-git-send-email-junjie.j.chen@intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v4] doc: add driver limitation for vhost dequeue zero copy 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, 19 Mar 2018 06:57:00 -0000 > -----Original Message----- > From: Chen, Junjie J > Sent: Thursday, March 15, 2018 12:24 AM > To: Tan, Jianfeng; maxime.coquelin@redhat.com; yliu@fridaylinux.org > Cc: dev@dpdk.org; Chen, Junjie J > Subject: [PATCH v4] doc: add driver limitation for vhost dequeue zero cop= y >=20 > In vhost-switch example, when binding nic to vfio-pci with iommu enabled, > dequeue zero copy cannot work in VM2NIC mode due to no iommu dma > mapping > is setup for guest memory currently. >=20 > Signed-off-by: Junjie Chen Reviewed-by: Jianfeng Tan Thanks! > --- > Changes in V4: > - make words more accurate > Changes in V3: > - update limitation to iommu > Changes in V2: > - add doc in vhost lib > doc/guides/prog_guide/vhost_lib.rst | 5 +++++ > doc/guides/sample_app_ug/vhost.rst | 5 ++++- > 2 files changed, 9 insertions(+), 1 deletion(-) >=20 > diff --git a/doc/guides/prog_guide/vhost_lib.rst > b/doc/guides/prog_guide/vhost_lib.rst > index 18227b6..b49e36e 100644 > --- a/doc/guides/prog_guide/vhost_lib.rst > +++ b/doc/guides/prog_guide/vhost_lib.rst > @@ -83,6 +83,11 @@ The following is an overview of some key Vhost API > functions: > of those segments, thus the fewer the segments, the quicker we wil= l get > the mapping. NOTE: we may speed it by using tree searching in futu= re. >=20 > + * zero copy can not work when using vfio-pci with iommu mode current= ly, > this > + is because we don't setup iommu dma mapping for guest memory. If > you have > + to use vfio-pci driver, please insert vfio-pci kernel module in no= iommu > + mode. > + > - ``RTE_VHOST_USER_IOMMU_SUPPORT`` >=20 > IOMMU support will be enabled when this flag is set. It is disabled = by > diff --git a/doc/guides/sample_app_ug/vhost.rst > b/doc/guides/sample_app_ug/vhost.rst > index a4bdc6a..f0bb169 100644 > --- a/doc/guides/sample_app_ug/vhost.rst > +++ b/doc/guides/sample_app_ug/vhost.rst > @@ -147,7 +147,10 @@ retries on an RX burst, it takes effect only when rx > retry is enabled. The > default value is 15. >=20 > **--dequeue-zero-copy** > -Dequeue zero copy will be enabled when this option is given. > +Dequeue zero copy will be enabled when this option is given. it is worth= to > +note that if NIC is binded to driver with iommu enabled, dequeue zero co= py > +cannot work at VM2NIC mode (vm2vm=3D0) due to currently we don't setup > iommu > +dma mapping for guest memory. >=20 > **--vlan-strip 0|1** > VLAN strip option is removed, because different NICs have different > behaviors > -- > 2.0.1