Re: [PATCH net-next v2 4/4] af_vsock: Assign the vsock transport considering the vsock address flags

[Paraschiv, Andra-Irina]

On 07/12/2020 12:00, Stefano Garzarella wrote:
> On Fri, Dec 04, 2020 at 07:02:35PM +0200, Andra Paraschiv wrote:
> > The vsock flags field can be 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 flags value (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 VMADDR_FLAG_TO_HOST flag
> > is set. For the other use cases, the vsock transport assignment logic is
> > not changed.
> >
> > Changelog
> >
> > v1 -> v2
> >
> > * Use bitwise operator to check the vsock flag.
> > * Use the updated "VMADDR_FLAG_TO_HOST" flag naming.
> > * Merge the checks for the g2h transport assignment in one "if" block.
> >
> > Signed-off-by: Andra Paraschiv <andraprs@xxxxxxxxxx>
> > ---
> > net/vmw_vsock/af_vsock.c | 9 +++++++--
> > 1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> > index 83d035eab0b05..66e643c3b5f85 100644
> > --- a/net/vmw_vsock/af_vsock.c
> > +++ b/net/vmw_vsock/af_vsock.c
> > @@ -421,7 +421,8 @@ static void vsock_deassign_transport(struct 
> > vsock_sock *vsk)
> >  * 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 or h2g is not loaded or remote 
> > flags field
> > + *    includes VMADDR_FLAG_TO_HOST flag value, 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)
> > @@ -429,6 +430,7 @@ 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_flags;
> >       int ret;
> >
> >       /* If the packet is coming with the source and destination CIDs 
> > higher
> > @@ -443,6 +445,8 @@ int vsock_assign_transport(struct vsock_sock 
> > *vsk, struct vsock_sock *psk)
> >           vsk->remote_addr.svm_cid > VMADDR_CID_HOST)
> >               vsk->remote_addr.svm_flags |= VMADDR_FLAG_TO_HOST;
> >
> > +      remote_flags = vsk->remote_addr.svm_flags;
> > +
> >       switch (sk->sk_type) {
> >       case SOCK_DGRAM:
> >               new_transport = transport_dgram;
> > @@ -450,7 +454,8 @@ 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_cid <= VMADDR_CID_HOST || !transport_h2g)
> > +              else if (remote_cid <= VMADDR_CID_HOST || 
> > !transport_h2g ||
> > +                       (remote_flags & VMADDR_FLAG_TO_HOST) == 
> > VMADDR_FLAG_TO_HOST)
>
> Maybe "remote_flags & VMADDR_FLAG_TO_HOST" should be enough, but the
> patch is okay:
>
> Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>

Done, updated to have only the bitwise logic, without the comparison.

Thanks,
Andra

> >                       new_transport = transport_g2h;
> >               else
> >                       new_transport = transport_h2g;
> > --
> > 2.20.1 (Apple Git-117)
> >
> >
> >
> >
> > Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. 
> > Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. 
> > Registered in Romania. Registration number J22/2621/2005.




Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in Romania. Registration number J22/2621/2005.