In vhost-switch example, when binding nic to vfio-pci, 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.c...@intel.com> --- doc/guides/sample_app_ug/vhost.rst | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/doc/guides/sample_app_ug/vhost.rst b/doc/guides/sample_app_ug/vhost.rst index a4bdc6a..1591a31 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 vfio-pci driver, 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