| Message ID | 20180112145658.17121-2-maxime.coquelin@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jan 12, 2018 at 03:56:55PM +0100, Maxime Coquelin wrote: > The number of queues supported by the slave is queried with > message VHOST_USER_GET_QUEUE_NUM, not with message > VHOST_USER_GET_PROTOCOL_FEATURES. > > Also, looking at master and slave implemntations, the payload > returned by the slave is the number of queue pairs supported > by the slave, not the number of queues. virtio doesn't have a concept of queue pairs. virtio net does have a concept of a tx/rx pair for purposes of steering. Would this be a slave bug then? I've applied the 1st chunk for now. > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> > --- > docs/interop/vhost-user.txt | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt > index d49444e037..8a14191a1e 100644 > --- a/docs/interop/vhost-user.txt > +++ b/docs/interop/vhost-user.txt > @@ -214,8 +214,8 @@ Multiple queue is treated as a protocol extension, hence the slave has to > implement protocol features first. The multiple queues feature is supported > only when the protocol feature VHOST_USER_PROTOCOL_F_MQ (bit 0) is set. > > -The max number of queues the slave supports can be queried with message > -VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the number of > +The max number of queue pairs the slave supports can be queried with message > +VHOST_USER_GET_QUEUE_NUM. Master should stop when the number of > requested queues is bigger than that. > > As all queues share one connection, the master uses a unique index for each > @@ -537,7 +537,7 @@ Master message types > Master payload: N/A > Slave payload: u64 > > - Query how many queues the backend supports. This request should be > + Query how many queue pairs the backend supports. This request should be > sent only when VHOST_USER_PROTOCOL_F_MQ is set in queried protocol > features by VHOST_USER_GET_PROTOCOL_FEATURES. > > -- > 2.14.3
On 01/16/2018 04:00 AM, Michael S. Tsirkin wrote: > On Fri, Jan 12, 2018 at 03:56:55PM +0100, Maxime Coquelin wrote: >> The number of queues supported by the slave is queried with >> message VHOST_USER_GET_QUEUE_NUM, not with message >> VHOST_USER_GET_PROTOCOL_FEATURES. >> >> Also, looking at master and slave implemntations, the payload >> returned by the slave is the number of queue pairs supported >> by the slave, not the number of queues. > > virtio doesn't have a concept of queue pairs. virtio net does > have a concept of a tx/rx pair for purposes of steering. Ok, thanks for the clarification. I will have a look at how vhost-user SCSI implements it. > Would this be a slave bug then? If I'm not mistaken, the bug is in QEMU: VHOST_USER_GET_QUEUE_NUM is stored in (struct vhost_dev).max_queues. vhost_net_get_max_queues() returns (struct vhost_dev).max_queues. And vhost_user_start() from net/vhost-user.c calls vhost_net_get_max_queues() to get the max number of tx/rx pairs. If we want to fix QEMU, I think we will need a new flag for compatibility with older/current backends that assume it represent a queue pair. > I've applied the 1st chunk for now. Thanks. >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> >> --- >> docs/interop/vhost-user.txt | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt >> index d49444e037..8a14191a1e 100644 >> --- a/docs/interop/vhost-user.txt >> +++ b/docs/interop/vhost-user.txt >> @@ -214,8 +214,8 @@ Multiple queue is treated as a protocol extension, hence the slave has to >> implement protocol features first. The multiple queues feature is supported >> only when the protocol feature VHOST_USER_PROTOCOL_F_MQ (bit 0) is set. >> >> -The max number of queues the slave supports can be queried with message >> -VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the number of >> +The max number of queue pairs the slave supports can be queried with message >> +VHOST_USER_GET_QUEUE_NUM. Master should stop when the number of >> requested queues is bigger than that. >> >> As all queues share one connection, the master uses a unique index for each >> @@ -537,7 +537,7 @@ Master message types >> Master payload: N/A >> Slave payload: u64 >> >> - Query how many queues the backend supports. This request should be >> + Query how many queue pairs the backend supports. This request should be >> sent only when VHOST_USER_PROTOCOL_F_MQ is set in queried protocol >> features by VHOST_USER_GET_PROTOCOL_FEATURES. >> >> -- >> 2.14.3
diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt index d49444e037..8a14191a1e 100644 --- a/docs/interop/vhost-user.txt +++ b/docs/interop/vhost-user.txt @@ -214,8 +214,8 @@ Multiple queue is treated as a protocol extension, hence the slave has to implement protocol features first. The multiple queues feature is supported only when the protocol feature VHOST_USER_PROTOCOL_F_MQ (bit 0) is set. -The max number of queues the slave supports can be queried with message -VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the number of +The max number of queue pairs the slave supports can be queried with message +VHOST_USER_GET_QUEUE_NUM. Master should stop when the number of requested queues is bigger than that. As all queues share one connection, the master uses a unique index for each @@ -537,7 +537,7 @@ Master message types Master payload: N/A Slave payload: u64 - Query how many queues the backend supports. This request should be + Query how many queue pairs the backend supports. This request should be sent only when VHOST_USER_PROTOCOL_F_MQ is set in queried protocol features by VHOST_USER_GET_PROTOCOL_FEATURES.
The number of queues supported by the slave is queried with message VHOST_USER_GET_QUEUE_NUM, not with message VHOST_USER_GET_PROTOCOL_FEATURES. Also, looking at master and slave implemntations, the payload returned by the slave is the number of queue pairs supported by the slave, not the number of queues. Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> --- docs/interop/vhost-user.txt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)