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Re: [Qemu-devel] [RFC PATCH] configure: remove --enable-replication/--di
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC PATCH] configure: remove --enable-replication/--disable-replication |
Date: |
Mon, 6 Feb 2017 11:57:00 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
* Paolo Bonzini (address@hidden) wrote:
>
>
> On 03/02/2017 07:00, Stefan Hajnoczi wrote:
> > On Thu, Feb 02, 2017 at 07:05:30AM -0800, Paolo Bonzini wrote:
> >> The replication feature is a small amount of code, does not
> >> require any external library and unless used does not add
> >> anything to the guest's attack surface. Since any extra
> >> configure option affects maintainability on the other hand
> >> and is subject to bit rot, I think there is no need to
> >> make it configurable.
> >
> > I think the current state is good: replication is enabled by default but
> > can be compiled out if desired.
> >
> > Downstreams may not be comfortable supporting this feature yet since
> > it's incomplete. It's fair to offer an option to disable it, otherwise
> > downstreams will have to patch this themselves.
>
> I understand---I just am not sure where to draw the line because there's
> plenty of other incomplete features, hence the RFC. For example,
> record/replay cannot be enabled or disabled on the configure command
> line. That was the case even in the beginning, where it didn't support
> either block or character device replay.
The line is certainly fuzzy, but I think it's worth making the following
type of things configurable:
Features that have a large chunk of code
- dont lets try and configure tiny things on and off
That can be trivially configured
- lets not put big chunks of code around making them configurable
and that are incomplete
or are unused by large chunks of the users
Dave
> --enable-coroutine-pool is a relic of when Windows builds needed it, but
> all other --enable-* options require an external library or at least a
> specific operating system. See for example this patch:
>
> commit 52b53c04faab9f7a9879c8dc014930649a3e698d
> Author: Fam Zheng <address@hidden>
> Date: Wed Sep 10 14:17:51 2014 +0800
>
> block: Always compile virtio-blk dataplane
>
> Dataplane doesn't depend on linux-aio any more, so we don't need the
> compiling condition now.
>
> Configure options are kept but just print a message.
>
> Signed-off-by: Fam Zheng <address@hidden>
> Reviewed-by: Paolo Bonzini <address@hidden>
> Message-id: address@hidden
> Signed-off-by: Stefan Hajnoczi <address@hidden>
>
>
> I would actually prefer to remove many of the latter
> (--enable-vhost-net, --enable-vhost-scsi, --enable-vhost-socket) and
> just use default-configs. We are already doing it for ivshmem for example:
>
> CONFIG_IVSHMEM=$(CONFIG_EVENTFD)
>
> Paolo
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK