Re: [PATCH net-next v1 3/3] af_vsock: Assign the vsock transport considering the vsock address flag

[Paraschiv, Andra-Irina]

On 01/12/2020 18:23, Stefano Garzarella wrote:
> On Tue, Dec 01, 2020 at 05:25:05PM +0200, Andra Paraschiv wrote:
> > The vsock flag has been set in the connect and (listen) receive paths.
> >
> > When the vsock transport is assigned, the remote CID is used to
> > distinguish between types of connection.
> >
> > Use the vsock flag (in addition to the CID) from the remote address to
> > decide which vsock transport to assign. For the sibling VMs use case,
> > all the vsock packets need to be forwarded to the host, so always assign
> > the guest->host transport if the vsock flag is set. For the other use
> > cases, the vsock transport assignment logic is not changed.
> >
> > Signed-off-by: Andra Paraschiv <andraprs@xxxxxxxxxx>
> > ---
> > net/vmw_vsock/af_vsock.c | 15 +++++++++++----
> > 1 file changed, 11 insertions(+), 4 deletions(-)
> >
> > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> > index d10916ab45267..bafc1cb20abd4 100644
> > --- a/net/vmw_vsock/af_vsock.c
> > +++ b/net/vmw_vsock/af_vsock.c
> > @@ -419,16 +419,21 @@ static void vsock_deassign_transport(struct 
> > vsock_sock *vsk)
> >  * (e.g. during the connect() or when a connection request on a listener
> >  * socket is received).
> >  * The vsk->remote_addr is used to decide which transport to use:
> > - *  - remote CID == VMADDR_CID_LOCAL or g2h->local_cid or 
> > VMADDR_CID_HOST if
> > - *    g2h is not loaded, will use local transport;
> > - *  - remote CID <= VMADDR_CID_HOST will use guest->host transport;
> > - *  - remote CID > VMADDR_CID_HOST will use host->guest transport;
> > + *  - remote flag == VMADDR_FLAG_SIBLING_VMS_COMMUNICATION, will always
> > + *    forward the vsock packets to the host and use guest->host 
> > transport;
> > + *  - otherwise, going forward with the remote flag default value:
> > + *    - remote CID == VMADDR_CID_LOCAL or g2h->local_cid or 
> > VMADDR_CID_HOST
> > + *      if g2h is not loaded, will use local transport;
> > + *    - remote CID <= VMADDR_CID_HOST or h2g is not loaded, will use
> > + *      guest->host transport;
> > + *    - remote CID > VMADDR_CID_HOST will use host->guest transport;
> >  */
> > int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock 
> > *psk)
> > {
> >       const struct vsock_transport *new_transport;
> >       struct sock *sk = sk_vsock(vsk);
> >       unsigned int remote_cid = vsk->remote_addr.svm_cid;
> > +      unsigned short remote_flag = vsk->remote_addr.svm_flag;
> >       int ret;
> >
> >       switch (sk->sk_type) {
> > @@ -438,6 +443,8 @@ int vsock_assign_transport(struct vsock_sock 
> > *vsk, struct vsock_sock *psk)
> >       case SOCK_STREAM:
> >               if (vsock_use_local_transport(remote_cid))
> >                       new_transport = transport_local;
> > +              else if (remote_flag == 
> > VMADDR_FLAG_SIBLING_VMS_COMMUNICATION)
>
> Others flags can be added, so here we should use the bitwise AND
> operator to check if this flag is set.
>
> And what about merging with the next if clause?

Indeed, I'll update the codebase to use the bitwise operator. Then I can 
also merge all the checks corresponding to the g2h transport in a single 
if block.

Thanks,
Andra

> > +                      new_transport = transport_g2h;
> >               else if (remote_cid <= VMADDR_CID_HOST ||
> >               !transport_h2g)
> >                       new_transport = transport_g2h;
> >               else
> > --
> > 2.20.1 (Apple Git-117)




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