| Message ID | 1521044656-105962-1-git-send-email-junjie.j.chen@intel.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Maxime Coquelin |
| Headers | show |
| Context | Check | Description |
|---|---|---|
| ci/checkpatch | success | coding style OK |
| ci/Intel-compilation | success | Compilation OK |
> -----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 copy > > 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 <junjie.j.chen@intel.com> Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com> 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(-) > > 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 will get > the mapping. NOTE: we may speed it by using tree searching in future. > > + * zero copy can not work when using vfio-pci with iommu mode currently, > 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 noiommu > + mode. > + > - ``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=0) 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 > -- > 2.0.1
On 03/14/2018 05:24 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 <junjie.j.chen@intel.com> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com> John, as this is a doc patch for Vhost, does it go through the doc tree or through Virtio one? Thanks, Maxime > --- > 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(-) > > 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 will get > the mapping. NOTE: we may speed it by using tree searching in future. > > + * zero copy can not work when using vfio-pci with iommu mode currently, 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 noiommu > + mode. > + > - ``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=0) 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 >
On 03/29/2018 02:14 PM, Maxime Coquelin wrote: > > > On 03/14/2018 05:24 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 <junjie.j.chen@intel.com> > > Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com> > > John, as this is a doc patch for Vhost, does it go through the doc tree > or through Virtio one? Applied to dpdk-next-virtio/master Thanks, Maxime > Thanks, > Maxime >> --- >> 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(-) >> >> 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 >> will get >> the mapping. NOTE: we may speed it by using tree searching in >> future. >> + * zero copy can not work when using vfio-pci with iommu mode >> currently, 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 >> noiommu >> + mode. >> + >> - ``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=0) 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 >>
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 will get the mapping. NOTE: we may speed it by using tree searching in future. + * zero copy can not work when using vfio-pci with iommu mode currently, 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 noiommu + mode. + - ``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=0) 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
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 <junjie.j.chen@intel.com> --- 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(-)