X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fsample_app_ug%2Fvhost.rst;h=a71ada6549fa94388205455f17c2785ad0e99719;hb=44158b523b049b7c8ab16c70544bb601bd29f0d1;hp=da161a9a91ae93d020761fa38f9cc94f95f58d89;hpb=768274ebbd5e532134420146cc26b1ff4b607740;p=dpdk.git

diff --git a/doc/guides/sample_app_ug/vhost.rst b/doc/guides/sample_app_ug/vhost.rst
index da161a9a91..a71ada6549 100644
--- a/doc/guides/sample_app_ug/vhost.rst
+++ b/doc/guides/sample_app_ug/vhost.rst
@@ -78,7 +78,7 @@ could be done by:
 .. code-block:: console
 
    modprobe uio_pci_generic
-   $RTE_SDK/usertools/dpdk-devbind.py -b=uio_pci_generic 0000:00:04.0
+   $RTE_SDK/usertools/dpdk-devbind.py -b uio_pci_generic 0000:00:04.0
 
 Then start testpmd for packet forwarding testing.
 
@@ -116,7 +116,7 @@ will create it. Put simply, it's the server to create the socket file.
 The vm2vm parameter sets the mode of packet switching between guests in
 the host.
 
-- 0 disables vm2vm, impling that VM's packets will always go to the NIC port.
+- 0 disables vm2vm, implying that VM's packets will always go to the NIC port.
 - 1 means a normal mac lookup packet routing.
 - 2 means hardware mode packet forwarding between guests, it allows packets
   go to the NIC port, hardware L2 switch will determine which guest the
@@ -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 bound 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
@@ -155,6 +158,10 @@ when disabling VLAN strip. Such feature, which heavily depends on hardware,
 should be removed from this example to reduce confusion. Now, VLAN strip is
 enabled and cannot be disabled.
 
+**--builtin-net-driver**
+A very simple vhost-user net driver which demonstrates how to use the generic
+vhost APIs will be used when this option is given. It is disabled by default.
+
 Common Issues
 -------------
 
@@ -178,3 +185,19 @@ Common Issues
 * Failed to build DPDK in VM
 
   Make sure "-cpu host" QEMU option is given.
+
+* Device start fails if NIC's max queues > the default number of 128
+
+  mbuf pool size is dependent on the MAX_QUEUES configuration, if NIC's
+  max queue number is larger than 128, device start will fail due to
+  insufficient mbuf.
+
+  Change the default number to make it work as below, just set the number
+  according to the NIC's property. ::
+
+      make EXTRA_CFLAGS="-DMAX_QUEUES=320"
+
+* Option "builtin-net-driver" is incompatible with QEMU
+
+  QEMU vhost net device start will fail if protocol feature is not negotiated.
+  DPDK virtio-user pmd can be the replacement of QEMU.