Re: [PATCH-for-9.1 v2 2/3] migration: Remove RDMA protocol handling

From: "Zhijian Li (Fujitsu)" via <qemu-devel@nongnu.org>
To: Peter Xu <peterx@redhat.com>, Jinpu Wang <jinpu.wang@ionos.com>
Cc: "Yu Zhang" <yu.zhang@ionos.com>,
	"Elmar Gerdes" <elmar.gerdes@ionos.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"Yuval Shaia" <yuval.shaia.ml@gmail.com>,
	"Kevin Wolf" <kwolf@redhat.com>,
	"Prasanna Kumar Kalever" <prasanna.kalever@redhat.com>,
	"Cornelia Huck" <cohuck@redhat.com>,
	"Michael Roth" <michael.roth@amd.com>,
	"Prasanna Kumar Kalever" <prasanna4324@gmail.com>,
	"integration@gluster.org" <integration@gluster.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"qemu-block@nongnu.org" <qemu-block@nongnu.org>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"devel@lists.libvirt.org" <devel@lists.libvirt.org>,
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	"Song Gao" <gaosong@loongson.cn>,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Wainer dos Santos Moschetta" <wainersm@redhat.com>,
	"Beraldo Leal" <bleal@redhat.com>,
	"arei.gonglei@huawei.com" <arei.gonglei@huawei.com>,
	"pannengyuan@huawei.com" <pannengyuan@huawei.com>
Subject: Re: [PATCH-for-9.1 v2 2/3] migration: Remove RDMA protocol handling
Date: Wed, 10 Apr 2024 02:28:59 +0000	[thread overview]
Message-ID: <082a21b0-d4d1-9f6c-24b5-bee56263008e@fujitsu.com> (raw)
In-Reply-To: <ZhWa0YeAb9ySVKD1@x1n>

on 4/10/2024 3:46 AM, Peter Xu wrote:

>> Is there document/link about the unittest/CI for migration tests, Why
>> are those tests missing?
>> Is it hard or very special to set up an environment for that? maybe we
>> can help in this regards.
> See tests/qtest/migration-test.c.  We put most of our migration tests
> there and that's covered in CI.
>
> I think one major issue is CI systems don't normally have rdma devices.
> Can rdma migration test be carried out without a real hardware?

Yeah,  RXE aka. SOFT-RoCE is able to emulate the RDMA, for example
$ sudo rdma link add rxe_eth0 type rxe netdev eth0  # on host
then we can get a new RDMA interface "rxe_eth0".
This new RDMA interface is able to do the QEMU RDMA migration.

Also, the loopback(lo) device is able to emulate the RDMA interface 
"rxe_lo", however when
I tried(years ago) to do RDMA migration over this 
interface(rdma:127.0.0.1:3333) , it got something wrong.
So i gave up enabling the RDMA migration qtest at that time.

Thanks
Zhijian

>
>>> It seems there can still be people joining this discussion.  I'll hold off
>>> a bit on merging this patch to provide enough window for anyone to chim in.
>> Thx for discussion and understanding.
> Thanks for all these inputs so far.  These can help us make a wiser and
> clearer step no matter which way we choose.