From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 43F5C5F2F for ; Tue, 13 Mar 2018 10:19:58 +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 fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Mar 2018 02:19:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,464,1515484800"; d="scan'208";a="24752856" Received: from fmsmsx106.amr.corp.intel.com ([10.18.124.204]) by orsmga008.jf.intel.com with ESMTP; 13 Mar 2018 02:19:56 -0700 Received: from fmsmsx112.amr.corp.intel.com (10.18.116.6) by FMSMSX106.amr.corp.intel.com (10.18.124.204) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 13 Mar 2018 02:19:56 -0700 Received: from shsmsx103.ccr.corp.intel.com (10.239.4.69) by FMSMSX112.amr.corp.intel.com (10.18.116.6) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 13 Mar 2018 02:19:56 -0700 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.166]) by SHSMSX103.ccr.corp.intel.com ([169.254.4.235]) with mapi id 14.03.0319.002; Tue, 13 Mar 2018 17:19:53 +0800 From: "Chen, Junjie J" To: "Tan, Jianfeng" , "yliu@fridaylinux.org" , "maxime.coquein@redhat.com" CC: "dev@dpdk.org" Thread-Topic: [PATCH v3] doc: add driver limitation for vhost dequeue zero copy Thread-Index: AQHTt05qZg+udadHtku1r0jWAlxii6PLa/CAgAJ+FIA= Date: Tue, 13 Mar 2018 09:19:51 +0000 Message-ID: References: <1519723268-28723-1-git-send-email-junjie.j.chen@intel.com> <1520590048-151284-1-git-send-email-junjie.j.chen@intel.com> <3d82fe68-5f76-7f38-ffb7-08cc4021da53@intel.com> In-Reply-To: <3d82fe68-5f76-7f38-ffb7-08cc4021da53@intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-ctpclassification: CTP_NT x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNDVmZWQ0NmUtNTQyZS00ZWUyLWEwOWMtYzFmOGFjYzJlNDdkIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjIuNS4xOCIsIlRydXN0ZWRMYWJlbEhhc2giOiIrTHdqcGNBRVNFR1Z0NERzdXZON1ZqWlFsRmJkUitINExDd3ZPbGlYaUVUUFhZXC83OElsWGhhRUlvYnVqTHJLcyJ9 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 v3] 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: Tue, 13 Mar 2018 09:19:58 -0000 Hi Jianfeng. > -----Original Message----- > From: Tan, Jianfeng > Sent: Monday, March 12, 2018 11:15 AM > To: Chen, Junjie J ; yliu@fridaylinux.org; > maxime.coquein@redhat.com > Cc: dev@dpdk.org > Subject: Re: [PATCH v3] doc: add driver limitation for vhost dequeue zero= copy >=20 >=20 >=20 > On 3/9/2018 6:07 PM, Junjie Chen wrote: > > 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. > > > > Signed-off-by: Junjie Chen > > --- > > 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(-) > > > > diff --git a/doc/guides/prog_guide/vhost_lib.rst > > b/doc/guides/prog_guide/vhost_lib.rst > > index 18227b6..06d214f 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 = will > get > > the mapping. NOTE: we may speed it by using tree searching in > future. > > > > + * zero copy does not work when using driver with iommu mode > > + currently, this >=20 > Considering FreeBSD driver nic_uio does not support iommu, we can make > "driver" more explicitly. For example, >=20 > "driver with iommu mode" -> "vfio-pci with iommu mode" Will update. >=20 > > + is because we don't setup iommu dma mapping for guest memory. >=20 > > For example, when you bind device to vfio-pci driver, you need to set d= river to > work in noiommu mode. >=20 > Reword the above sentence a little bit: > "If vfio-pci is a must in your case, insert vfio-pci kernel module in noi= ommu > mode." Will update, thanks. > > + > > - ``RTE_VHOST_USER_IOMMU_SUPPORT`` > > > > 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. > > > > **--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 copy cannot work at VM2NIC mode (vm2vm=3D0) due to > > +currently we don't setup iommu dma mapping for guest memory. > > > > **--vlan-strip 0|1** > > VLAN strip option is removed, because different NICs have different > > behaviors