Re: [Qemu-devel] [PATCH v10 4/7] vhost-user: add VHOST_USER_GET_QUEUE_NUM message

[Yuanhan Liu]

On Tue, Sep 22, 2015 at 05:56:16PM +0800, Jason Wang wrote:
> 
> 
> On 09/18/2015 10:58 PM, Yuanhan Liu wrote:
> > This is for querying how many queues the backend supports if it has mq
> > support(when VHOST_USER_PROTOCOL_F_MQ flag is set from the quried
> > protocol features).
> >
> > vhost_net_get_max_queues() is the interface to export that value, and
> > to tell if the backend supports # of queues user requested, which is
> > done in the following patch.
> >
> > Signed-off-by: Yuanhan Liu <address@hidden>
> > ---
> >  docs/specs/vhost-user.txt | 11 +++++++++++
> >  hw/net/vhost_net.c        |  7 +++++++
> >  hw/virtio/vhost-user.c    | 15 ++++++++++++++-
> >  include/hw/virtio/vhost.h |  1 +
> >  include/net/vhost_net.h   |  1 +
> >  5 files changed, 34 insertions(+), 1 deletion(-)
> >
> > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> > index ccbbcbb..43db9b4 100644
> > --- a/docs/specs/vhost-user.txt
> > +++ b/docs/specs/vhost-user.txt
> > @@ -301,3 +301,14 @@ Message types
> >        Bits (0-7) of the payload contain the vring index. Bit 8 is the
> >        invalid FD flag. This flag is set when there is no file descriptor
> >        in the ancillary data.
> > +
> > + * VHOST_USER_GET_QUEUE_NUM
> > +
> > +      Id: 17
> > +      Equivalent ioctl: N/A
> > +      Master payload: N/A
> > +      Slave payload: u64
> > +
> > +      Query how many queues the backend supports. This request should be
> > +      sent only when VHOST_USER_PROTOCOL_F_MQ is set in quried protocol
> > +      features by VHOST_USER_GET_PROTOCOL_FEATURES.
> > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > index b7d29b7..bc88006 100644
> > --- a/hw/net/vhost_net.c
> > +++ b/hw/net/vhost_net.c
> > @@ -122,6 +122,11 @@ void vhost_net_ack_features(struct vhost_net *net, 
> > uint64_t features)
> >      vhost_ack_features(&net->dev, vhost_net_get_feature_bits(net), 
> > features);
> >  }
> >  
> > +uint64_t vhost_net_get_max_queues(VHostNetState *net)
> > +{
> > +    return net->dev.max_queues;
> > +}
> 
> Looks like need a dummy function for !CONFIG_VHOST_NET.

Yes, it is. A such build error report has been already reported by some
one.

        --yliu
> 
> > +
> >  static int vhost_net_get_fd(NetClientState *backend)
> >  {
> >      switch (backend->info->type) {
> > @@ -144,6 +149,8 @@ struct vhost_net *vhost_net_init(VhostNetOptions 
> > *options)
> >          goto fail;
> >      }
> >  
> > +    net->dev.max_queues = 1;
> > +
> >      if (backend_kernel) {
> >          r = vhost_net_get_fd(options->net_backend);
> >          if (r < 0) {
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index 9cb2f52..694fde5 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -25,7 +25,9 @@
> >  
> >  #define VHOST_MEMORY_MAX_NREGIONS    8
> >  #define VHOST_USER_F_PROTOCOL_FEATURES 30
> > -#define VHOST_USER_PROTOCOL_FEATURE_MASK 0x0ULL
> > +#define VHOST_USER_PROTOCOL_FEATURE_MASK 0x1ULL
> > +
> > +#define VHOST_USER_PROTOCOL_F_MQ    0
> >  
> >  typedef enum VhostUserRequest {
> >      VHOST_USER_NONE = 0,
> > @@ -45,6 +47,7 @@ typedef enum VhostUserRequest {
> >      VHOST_USER_SET_VRING_ERR = 14,
> >      VHOST_USER_GET_PROTOCOL_FEATURES = 15,
> >      VHOST_USER_SET_PROTOCOL_FEATURES = 16,
> > +    VHOST_USER_GET_QUEUE_NUM = 17,
> >      VHOST_USER_MAX
> >  } VhostUserRequest;
> >  
> > @@ -211,6 +214,7 @@ static int vhost_user_call(struct vhost_dev *dev, 
> > unsigned long int request,
> >      switch (msg_request) {
> >      case VHOST_USER_GET_FEATURES:
> >      case VHOST_USER_GET_PROTOCOL_FEATURES:
> > +    case VHOST_USER_GET_QUEUE_NUM:
> >          need_reply = 1;
> >          break;
> >  
> > @@ -315,6 +319,7 @@ static int vhost_user_call(struct vhost_dev *dev, 
> > unsigned long int request,
> >          switch (msg_request) {
> >          case VHOST_USER_GET_FEATURES:
> >          case VHOST_USER_GET_PROTOCOL_FEATURES:
> > +        case VHOST_USER_GET_QUEUE_NUM:
> >              if (msg.size != sizeof(m.u64)) {
> >                  error_report("Received bad msg size.");
> >                  return -1;
> > @@ -366,6 +371,14 @@ static int vhost_user_init(struct vhost_dev *dev, void 
> > *opaque)
> >          if (err < 0) {
> >              return err;
> >          }
> > +
> > +        /* query the max queues we support if backend supports Multiple 
> > Queue */
> > +        if (dev->protocol_features & (1ULL << VHOST_USER_PROTOCOL_F_MQ)) {
> > +            err = vhost_user_call(dev, VHOST_USER_GET_QUEUE_NUM, 
> > &dev->max_queues);
> > +            if (err < 0) {
> > +                return err;
> > +            }
> > +        }
> >      }
> >  
> >      return 0;
> > diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> > index 6467c73..c3758f3 100644
> > --- a/include/hw/virtio/vhost.h
> > +++ b/include/hw/virtio/vhost.h
> > @@ -48,6 +48,7 @@ struct vhost_dev {
> >      unsigned long long acked_features;
> >      unsigned long long backend_features;
> >      unsigned long long protocol_features;
> > +    unsigned long long max_queues;
> >      bool started;
> >      bool log_enabled;
> >      unsigned long long log_size;
> > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
> > index 840d4b1..8db723e 100644
> > --- a/include/net/vhost_net.h
> > +++ b/include/net/vhost_net.h
> > @@ -13,6 +13,7 @@ typedef struct VhostNetOptions {
> >      void *opaque;
> >  } VhostNetOptions;
> >  
> > +uint64_t vhost_net_get_max_queues(VHostNetState *net);
> >  struct vhost_net *vhost_net_init(VhostNetOptions *options);
> >  
> >  int vhost_net_start(VirtIODevice *dev, NetClientState *ncs, int 
> > total_queues);