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* [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description
@ 2020-02-14 13:07 Stefano Garzarella
  2020-02-14 19:35 ` Stefan Hajnoczi
  2020-02-17 13:55 ` Jorgen Hansen
  0 siblings, 2 replies; 4+ messages in thread
From: Stefano Garzarella @ 2020-02-14 13:07 UTC (permalink / raw)
  To: mtk.manpages
  Cc: Jorgen Hansen, linux-man, Stefan Hajnoczi, Dexuan Cui, netdev

Linux 5.6 added the new well-known VMADDR_CID_LOCAL for
local communication.

This patch explains how to use it and remove the legacy
VMADDR_CID_RESERVED no longer available.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
v2:
    * rephrased "Local communication" description [Stefan]
    * added a mention of previous versions that supported
      loopback only in the guest [Stefan]
---
 man7/vsock.7 | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/man7/vsock.7 b/man7/vsock.7
index c5ffcf07d..78ac22b1e 100644
--- a/man7/vsock.7
+++ b/man7/vsock.7
@@ -127,8 +127,8 @@ There are several special addresses:
 means any address for binding;
 .B VMADDR_CID_HYPERVISOR
 (0) is reserved for services built into the hypervisor;
-.B VMADDR_CID_RESERVED
-(1) must not be used;
+.B VMADDR_CID_LOCAL
+(1) is the well-known address for local communication (loopback);
 .B VMADDR_CID_HOST
 (2)
 is the well-known address of the host.
@@ -164,6 +164,16 @@ Consider using
 .B VMADDR_CID_ANY
 when binding instead of getting the local CID with
 .BR IOCTL_VM_SOCKETS_GET_LOCAL_CID .
+.SS Local communication
+The
+.B VMADDR_CID_LOCAL
+(1) directs packets to the same host that generated them. This is useful
+for testing applications on a single host and for debugging.
+.PP
+The local CID obtained with
+.BR IOCTL_VM_SOCKETS_GET_LOCAL_CID
+can be used for the same purpose, but it is preferable to use
+.B VMADDR_CID_LOCAL .
 .SH ERRORS
 .TP
 .B EACCES
@@ -222,6 +232,11 @@ are valid.
 Support for VMware (VMCI) has been available since Linux 3.9.
 KVM (virtio) is supported since Linux 4.8.
 Hyper-V is supported since Linux 4.14.
+.PP
+VMADDR_CID_LOCAL is supported since Linux 5.6.
+Local communication in the guest and on the host is available since Linux 5.6.
+Previous versions partially supported it only in the guest and only with some
+transports (VMCI and virtio).
 .SH SEE ALSO
 .BR bind (2),
 .BR connect (2),
-- 
2.24.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description
  2020-02-14 13:07 [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description Stefano Garzarella
@ 2020-02-14 19:35 ` Stefan Hajnoczi
  2020-02-17 13:55 ` Jorgen Hansen
  1 sibling, 0 replies; 4+ messages in thread
From: Stefan Hajnoczi @ 2020-02-14 19:35 UTC (permalink / raw)
  To: Stefano Garzarella
  Cc: mtk.manpages, Jorgen Hansen, linux-man, Dexuan Cui, netdev

[-- Attachment #1: Type: text/plain, Size: 398 bytes --]

On Fri, Feb 14, 2020 at 02:07:49PM +0100, Stefano Garzarella wrote:
> @@ -164,6 +164,16 @@ Consider using
>  .B VMADDR_CID_ANY
>  when binding instead of getting the local CID with
>  .BR IOCTL_VM_SOCKETS_GET_LOCAL_CID .
> +.SS Local communication
> +The

"The" is unnatural here, I don't think native speakers would use it.
Simply saying "VMADDR_CID_LOCAL (1) directs packets ..." is more common.

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* RE: [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description
  2020-02-14 13:07 [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description Stefano Garzarella
  2020-02-14 19:35 ` Stefan Hajnoczi
@ 2020-02-17 13:55 ` Jorgen Hansen
  2020-02-17 17:27   ` Stefano Garzarella
  1 sibling, 1 reply; 4+ messages in thread
From: Jorgen Hansen @ 2020-02-17 13:55 UTC (permalink / raw)
  To: Stefano Garzarella, mtk.manpages
  Cc: linux-man, Stefan Hajnoczi, Dexuan Cui, netdev

> From: Stefano Garzarella [mailto:sgarzare@redhat.com]
> Sent: Friday, February 14, 2020 2:08 PM
> To: mtk.manpages@gmail.com
> Cc: Jorgen Hansen <jhansen@vmware.com>; linux-man@vger.kernel.org;
> Stefan Hajnoczi <stefanha@redhat.com>; Dexuan Cui
> <decui@microsoft.com>; netdev@vger.kernel.org
> Subject: [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description
> 
> Linux 5.6 added the new well-known VMADDR_CID_LOCAL for local
> communication.
> 
> This patch explains how to use it and remove the legacy
> VMADDR_CID_RESERVED no longer available.
> 
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
> v2:
>     * rephrased "Local communication" description [Stefan]
>     * added a mention of previous versions that supported
>       loopback only in the guest [Stefan]
> ---


> @@ -222,6 +232,11 @@ are valid.
>  Support for VMware (VMCI) has been available since Linux 3.9.
>  KVM (virtio) is supported since Linux 4.8.
>  Hyper-V is supported since Linux 4.14.
> +.PP
> +VMADDR_CID_LOCAL is supported since Linux 5.6.
> +Local communication in the guest and on the host is available since Linux
> 5.6.
> +Previous versions partially supported it only in the guest and only
> +with some transports (VMCI and virtio).

Maybe rephrase the last part slightly to something like:

Previous versions only supported local communication within a guest (not on the host),
and only with some transports (VMCI and virtio).

Otherwise, looks good to me. Thanks for making this update.

Reviewed-by: Jorgen Hansen <jhansen@vmware.com>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description
  2020-02-17 13:55 ` Jorgen Hansen
@ 2020-02-17 17:27   ` Stefano Garzarella
  0 siblings, 0 replies; 4+ messages in thread
From: Stefano Garzarella @ 2020-02-17 17:27 UTC (permalink / raw)
  To: Jorgen Hansen
  Cc: mtk.manpages, linux-man, Stefan Hajnoczi, Dexuan Cui, netdev

On Mon, Feb 17, 2020 at 01:55:58PM +0000, Jorgen Hansen wrote:
> > From: Stefano Garzarella [mailto:sgarzare@redhat.com]
> > Sent: Friday, February 14, 2020 2:08 PM
> > To: mtk.manpages@gmail.com
> > Cc: Jorgen Hansen <jhansen@vmware.com>; linux-man@vger.kernel.org;
> > Stefan Hajnoczi <stefanha@redhat.com>; Dexuan Cui
> > <decui@microsoft.com>; netdev@vger.kernel.org
> > Subject: [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description
> > 
> > Linux 5.6 added the new well-known VMADDR_CID_LOCAL for local
> > communication.
> > 
> > This patch explains how to use it and remove the legacy
> > VMADDR_CID_RESERVED no longer available.
> > 
> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > ---
> > v2:
> >     * rephrased "Local communication" description [Stefan]
> >     * added a mention of previous versions that supported
> >       loopback only in the guest [Stefan]
> > ---
> 
> 
> > @@ -222,6 +232,11 @@ are valid.
> >  Support for VMware (VMCI) has been available since Linux 3.9.
> >  KVM (virtio) is supported since Linux 4.8.
> >  Hyper-V is supported since Linux 4.14.
> > +.PP
> > +VMADDR_CID_LOCAL is supported since Linux 5.6.
> > +Local communication in the guest and on the host is available since Linux
> > 5.6.
> > +Previous versions partially supported it only in the guest and only
> > +with some transports (VMCI and virtio).
> 
> Maybe rephrase the last part slightly to something like:
> 
> Previous versions only supported local communication within a guest (not on the host),
> and only with some transports (VMCI and virtio).

I think it is better, I'll send a v3 with this part changed :-)

> 
> Otherwise, looks good to me. Thanks for making this update.
> 
> Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
> 

Thanks,
Stefano


^ permalink raw reply	[flat|nested] 4+ messages in thread

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2020-02-14 13:07 [PATCH v2] vsock.7: add VMADDR_CID_LOCAL description Stefano Garzarella
2020-02-14 19:35 ` Stefan Hajnoczi
2020-02-17 13:55 ` Jorgen Hansen
2020-02-17 17:27   ` Stefano Garzarella

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