From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
To: Stefano Garzarella <sgarzare@redhat.com>
Cc: mtk.manpages@gmail.com, Jorgen Hansen <jhansen@vmware.com>,
netdev@vger.kernel.org, linux-man@vger.kernel.org,
Stefan Hajnoczi <stefanha@redhat.com>,
Dexuan Cui <decui@microsoft.com>
Subject: Re: [PATCH v4] vsock.7: add VMADDR_CID_LOCAL description
Date: Sat, 14 Mar 2020 23:02:19 +0100 [thread overview]
Message-ID: <b3289245-ba42-24d4-b96c-267d09b2e37a@gmail.com> (raw)
In-Reply-To: <20200218155435.172860-1-sgarzare@redhat.com>
Hello Stefano,
On 2/18/20 4:54 PM, Stefano Garzarella wrote:
> 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.
>
> Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
> v4:
> * removed "The" in the "Local communication" section [Stefan]
> v3:
> * rephrased "Previous versions" part [Jorgen]
> v2:
> * rephrased "Local communication" description [Stefan]
> * added a mention of previous versions that supported
> loopback only in the guest [Stefan]
Thanks. Patch applied.
Cheers,
Michael
> ---
> man7/vsock.7 | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/man7/vsock.7 b/man7/vsock.7
> index c5ffcf07d..fa2c6e17e 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 +164,15 @@ 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
> +.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 +231,11 @@ 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 only supported local communication within a guest
> +(not on the host), and only with some transports (VMCI and virtio).
> .SH SEE ALSO
> .BR bind (2),
> .BR connect (2),
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
prev parent reply other threads:[~2020-03-15 2:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 15:54 [PATCH v4] vsock.7: add VMADDR_CID_LOCAL description Stefano Garzarella
2020-02-19 11:21 ` Stefan Hajnoczi
2020-03-14 22:02 ` Michael Kerrisk (man-pages) [this message]
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