From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Zhiyong Yang <zhiyong.yang@intel.com>
Cc: dev@dpdk.org, maxime.coquelin@redhat.com, ciara.loftus@intel.com
Subject: Re: [dpdk-dev] [PATCH] vhost: fix MQ fails to startup
Date: Thu, 27 Apr 2017 16:12:03 +0800 [thread overview]
Message-ID: <20170427081203.GK11512@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <1493274893-40764-1-git-send-email-zhiyong.yang@intel.com>
On Thu, Apr 27, 2017 at 02:34:53PM +0800, Zhiyong Yang wrote:
> vhost since dpdk17.02 + qemu2.7 and above will cause failures of
> new connection when negotiating to set MQ. (one queue pair works
> well).Because there exist some bugs in qemu code when introducing
> VHOST_USER_PROTOCOL_F_REPLY_ACK to qemu. when dealing with the vhost
> message VHOST_USER_SET_MEM_TABLE for the second time, qemu indeed
> doesn't send the messge (The message needs to be sent only once)but
> still will be waiting for dpdk's reply ack, then, qemu is always
> freezing. DPDK code works in the right way. But the feature
> VHOST_USER_PROTOCOL_F_REPLY_ACK has to be disabled by default at the
> dpdk side in order to avoid the feature support of DPDK + qemu at
> the same time. if doing like that, MQ can works well.
...
> Once Qemu bugs
> have been fixed and upstreamed, we can enable it.
As I have said, we should not enable it again, because there are already
few buggy QEMU releases out. We should make sure DPDK also works well with
them.
> Fixes: 73c8f9f69c6c("vhost: introduce reply ack feature")
That commit does nothing wrong. It's QEMU being buggy. That said, I will
not add such fixline. I will also use "workaround" instead of "fix" in
the title.
Also, this patch should be backported to stable release. So, you should
add:
Cc: stable@dpdk.org
Besides, please reformat you commit log a bit. For example, add space
after punctuation, use paragraph as possible, etc.
>
> Reported-by: Loftus, Ciara <ciara.loftus@intel.com>
No "," is allowed.
> Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
> ---
> lib/librte_vhost/vhost_user.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
> index 2ba22db..a3d2900 100644
> --- a/lib/librte_vhost/vhost_user.h
> +++ b/lib/librte_vhost/vhost_user.h
> @@ -52,7 +52,7 @@
> #define VHOST_USER_PROTOCOL_FEATURES ((1ULL << VHOST_USER_PROTOCOL_F_MQ) | \
> (1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD) |\
> (1ULL << VHOST_USER_PROTOCOL_F_RARP) | \
> - (1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK) | \
> + (0ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK) | \
> (1ULL << VHOST_USER_PROTOCOL_F_NET_MTU))
I think you might want to add a simple comment here, something like
/*
* disable REPLY_ACK feature to workaround the buggy QEMU implementation.
* Proved buggy QEMU includes v2.7 - v2.9.
*/
So, please send v2?
--yliu
next prev parent reply other threads:[~2017-04-27 8:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-27 6:34 Zhiyong Yang
2017-04-27 7:41 ` Loftus, Ciara
2017-04-27 7:56 ` Maxime Coquelin
2017-04-27 8:05 ` Maxime Coquelin
2017-04-27 8:24 ` Yang, Zhiyong
2017-04-27 8:32 ` Maxime Coquelin
2017-04-27 8:20 ` Yuanhan Liu
2017-04-27 8:52 ` Maxime Coquelin
2017-04-28 2:25 ` Yuanhan Liu
2017-04-28 7:23 ` Maxime Coquelin
2017-04-28 7:35 ` Yuanhan Liu
2017-04-28 7:39 ` Yuanhan Liu
2017-04-28 7:57 ` Maxime Coquelin
2017-04-28 8:00 ` Yuanhan Liu
2017-04-27 8:12 ` Yuanhan Liu [this message]
2017-04-27 8:32 ` Yang, Zhiyong
2017-04-27 9:41 ` [dpdk-dev] [PATCH v2] vhost: workaround " Zhiyong Yang
2017-04-27 10:00 ` Maxime Coquelin
2017-04-28 4:29 ` Yuanhan Liu
2017-05-10 2:07 ` Yang, Zhiyong
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