Re: [PATCH v2 3/7] multifd: adding multi-interface support for multifd on destination side

[Daniel P . Berrangé]

On Thu, Jul 21, 2022 at 07:56:16PM +0000, Het Gala wrote:
> i) Modified the format of qemu monitor command: 'migrate-incoming' by adding
>    a list, each element in the list to open socket listeners with a given
>    number of multifd channels.
> 
> ii) Qemu starts with -incoming flag defer and -multi-fd-incoming defer to
>     allow the modified 'migrate-incoming' command to be used.
> 
> iii) Format for -multi-fd-incoming flag as a comma separated string has been
>      added with each substring containing listener socket address and number
>      of sockets to open.
> 
> Suggested-by: Manish Mishra <manish.mishra@nutanix.com>
> Signed-off-by: Het Gala <het.gala@nutanix.com>


> diff --git a/qemu-options.hx b/qemu-options.hx
> index 79e00916a1..5555f0d2fd 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4479,6 +4479,24 @@ SRST
>      to issuing the migrate\_incoming to allow the migration to begin.
>  ERST
>  
> +DEF("multi-fd-incoming", HAS_ARG, QEMU_OPTION_multi_fd_incoming, \
> +    "-multi-fd-incoming 
> tcp:[host]:port[:channel][,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \
> +    "-multi-fd-incoming defer\n" \
> +    "                wait for the URI to be specified via\n" \
> +    "                multi_fd_migrate_incoming\n",
> +    QEMU_ARCH_ALL)
> +SRST
> +``-multi-fd-incoming 
> tcp:[host]:port[:channel][,to=maxport][,ipv4=on|off][,ipv6=on|off]``
> +    Prepare for multi-fd incoming migration, with multi-fd listening sockets
> +    on that connection. Default number of multi-fd channels is 2.
> +
> +``-multi-fd-incoming defer``
> +    Wait for the URI to be specified via multi_fd_migrate\_incoming. The
> +    monitor can be used to change settings (such as migration parameters)
> +    prior to issuing the multi_fd_migrate\_incoming to allow the migration
> +    to begin.
> +ERST

We should not be adding any new -multi-fd-incoming CLI parameter at all.
The CLI is so unsuitable for any complex configuration param and this
is a prime example. 

If anything we should fully deprecate anything that is not '-incoming defer'
such that we become 100% QMP/QAPI based for incoming migration config.


With regards,
Daniel
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