Re: [Qemu-devel] [PATCH v5 15/21] vhost user: add rarp sending after live migration for legacy guest

[Michael S. Tsirkin]

On Thu, Sep 24, 2015 at 05:53:05PM -0400, Marc-André Lureau wrote:
> Hi
> 
> ----- Original Message -----
> > On Thu, Sep 24, 2015 at 6:22 PM,  <address@hidden> wrote:
> > > From: Thibaut Collet <address@hidden>
> > >
> > > A new vhost user message is added to allow QEMU to ask to vhost user
> > > backend to
> > > broadcast a fake RARP after live migration for guest without 
> > > GUEST_ANNOUNCE
> > > capability.
> > >
> > > This new message is sent only if the backend supports the new
> > > VHOST_USER_PROTOCOL_F_RARP protocol feature.
> > > The payload of this new message is the MAC address of the guest (not known
> > > by
> > > the backend). The MAC address is copied in the first 6 bytes of a u64 to
> > > avoid
> > > to create a new payload message type.
> > >
> > > This new message has no equivalent ioctl so a new callback is added in the
> > > userOps structure to send the request.
> > >
> > > Upon reception of this new message the vhost user backend must generate 
> > > and
> > > broadcast a fake RARP request to notify the migration is terminated.
> > >
> > > Signed-off-by: Thibaut Collet <address@hidden>
> > > [Rebased and fixed checkpatch errors - Marc-André]
> > > Signed-off-by: Marc-André Lureau <address@hidden>
> > > ---
> > >  docs/specs/vhost-user.txt         | 15 +++++++++++++++
> > >  hw/net/vhost_net.c                | 17 +++++++++++++++++
> > >  hw/virtio/vhost-user.c            | 30 ++++++++++++++++++++++++++++++
> > >  include/hw/virtio/vhost-backend.h |  3 +++
> > >  include/net/vhost_net.h           |  1 +
> > >  net/vhost-user.c                  | 24 ++++++++++++++++++++++--
> > >  6 files changed, 88 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> > > index e0292a0..e0d71e2 100644
> > > --- a/docs/specs/vhost-user.txt
> > > +++ b/docs/specs/vhost-user.txt
> > > @@ -194,6 +194,7 @@ Protocol features
> > >
> > >  #define VHOST_USER_PROTOCOL_F_MQ             0
> > >  #define VHOST_USER_PROTOCOL_F_LOG_SHMFD      1
> > > +#define VHOST_USER_PROTOCOL_F_RARP           2
> > >
> > >  Message types
> > >  -------------
> > > @@ -381,3 +382,17 @@ Message types
> > >        Master payload: vring state description
> > >
> > >        Signal slave to enable or disable corresponding vring.
> > > +
> > > + * VHOST_USER_SEND_RARP
> > > +
> > > +      Id: 19
> > > +      Equivalent ioctl: N/A
> > > +      Master payload: u64
> > > +
> > > +      Ask vhost user backend to broadcast a fake RARP to notify the
> > > migration
> > > +      is terminated for guest that does not support GUEST_ANNOUNCE.
> > > +      Only legal if feature bit VHOST_USER_F_PROTOCOL_FEATURES is present
> > > in
> > > +      VHOST_USER_GET_FEATURES and protocol feature bit
> > > VHOST_USER_PROTOCOL_F_RARP
> > > +      is present in VHOST_USER_GET_PROTOCOL_FEATURES.
> > > +      The first 6 bytes of the payload contain the mac address of the
> > > guest to
> > > +      allow the vhost user backend to construct and broadcast the fake
> > > RARP.
> > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > > index 840f443..da66b64 100644
> > > --- a/hw/net/vhost_net.c
> > > +++ b/hw/net/vhost_net.c
> > > @@ -388,6 +388,18 @@ void vhost_net_cleanup(struct vhost_net *net)
> > >      g_free(net);
> > >  }
> > >
> > > +int vhost_net_notify_migration_done(struct vhost_net *net, char* 
> > > mac_addr)
> > > +{
> > > +    const VhostOps *vhost_ops = net->dev.vhost_ops;
> > > +    int r = -1;
> > > +
> > > +    if (vhost_ops->vhost_migration_done) {
> > > +        r = vhost_ops->vhost_migration_done(&net->dev, mac_addr);
> > > +    }
> > > +
> > > +    return r;
> > > +}
> > > +
> > >  bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
> > >  {
> > >      return vhost_virtqueue_pending(&net->dev, idx);
> > > @@ -479,6 +491,11 @@ void vhost_net_virtqueue_mask(VHostNetState *net,
> > > VirtIODevice *dev,
> > >  {
> > >  }
> > >
> > > +int vhost_net_notify_migration_done(struct vhost_net *net)
> > > +{
> > > +    return -1;
> > > +}
> > > +
> > >  VHostNetState *get_vhost_net(NetClientState *nc)
> > >  {
> > >      return 0;
> > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > > index 455caba..b7f3699 100644
> > > --- a/hw/virtio/vhost-user.c
> > > +++ b/hw/virtio/vhost-user.c
> > > @@ -10,6 +10,7 @@
> > >
> > >  #include "hw/virtio/vhost.h"
> > >  #include "hw/virtio/vhost-backend.h"
> > > +#include "hw/virtio/virtio-net.h"
> > >  #include "sysemu/char.h"
> > >  #include "sysemu/kvm.h"
> > >  #include "qemu/error-report.h"
> > > @@ -30,6 +31,7 @@
> > >  #define VHOST_USER_PROTOCOL_FEATURE_MASK 0x3ULL
> > >  #define VHOST_USER_PROTOCOL_F_MQ         0
> > >  #define VHOST_USER_PROTOCOL_F_LOG_SHMFD  1
> > > +#define VHOST_USER_PROTOCOL_F_RARP       2
> > 
> > The VHOST_USER_PROTOCOL_FEATURE_MASK  must be changed and set to 0x7ULL
> > 
Better, change VHOST_USER_PROTOCOL_FEATURE_MASK to be
calculated based on other macros.

> 
> Good catch (too many rebases, having a test would help to prevent this kind 
> of mistake)
> 
> thanks

So there will be v6 with a fix?

-- 
MST