Re: [PATCH] maintainers: claim responsability for xen

From: Thomas Monjalon <thomas@monjalon.net>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>
Cc: dev@dpdk.org, Joao Martins <joao.m.martins@oracle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Konrad Rzeszutek Wilk <konrad@kernel.org>,
	Xen-devel <xen-devel@lists.xenproject.org>,
	techboard@dpdk.org
Subject: Re: [PATCH] maintainers: claim responsability for xen
Date: Mon, 19 Jun 2017 15:22:26 +0200	[thread overview]
Message-ID: <3259340.9y2bTrEvHo@xps> (raw)
In-Reply-To: <ED26CBA2FAD1BF48A8719AEF02201E36511C7F5A@SHSMSX103.ccr.corp.intel.com>

Thanks Jianfeng for giving new ideas.

There is not much activity on Xen side.
Is there someone working on DPDK+Xen? Any news?

The technical board requested to re-consider Xen support in DPDK.
It will be discussed in the next techboard meeting:
	https://annuel.framapad.org/p/r.0c3cc4d1e011214183872a98f6b5c7db

11/05/2017 13:41, Tan, Jianfeng:
> Hi  Thomas and all,
> 
> Apologize for being an unqualified maintainer.
> 
> > -----Original Message-----
> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> 
> > Ping
> > 
> > The Xen dom0 support in DPDK seems dead.
> > 
> > Reminder:
> > Last time we talked about, it was because of a severe bug which is not
> > fixed yet:
> >         http://dpdk.org/ml/archives/dev/2016-July/044207.html
> 
> For this bug, we removed the userspace memset(0) and suppose it has been done by kernel, however, xen0 uses __get_free_pages() kernel API to map hugepages and reseve memseg, I think it makes sense to zero the hugepage for xen0 in rte_dom0_mm kernel module (instead of some special code for xen0 in userspace) to keep aligned behavior.
> 
> >         http://dpdk.org/ml/archives/dev/2016-July/044376.html
> 
> It does not make any sense to upstream a netfront PMD before we have a netback PMD, as the legacy netback driver would be the bottleneck. Anyone has plan on this? And a question mark keeps in my mind that is it a must to implement netback in dom0?
> 
> From another perspective, instead of using netfront/netback, we can also use virtio/vhost as the device model; however, xl tool in xen only supports vhost-kernel backend instead of vhost-user backend. So anyone has plan to enhance xl tool so that we can accelerate dom0 just using vswitch like OVS-DPDK?
> 
> A third solution is to use xenvirtio as the frontend, and vhost_xen as the backend. This solution is to use virtio ring on grant table mechanism of xen. Honestly, I don't even know if it still work now. And to make it more usable, better to upstream vhost_xen inside popular vswitch like OVS-DPDK.
> 
> > The request (9 months ago) was to give more time for feedbacks:
> >         http://dpdk.org/ml/archives/dev/2016-July/044847.html
> 
> Apologize again that I volunteer to maintain these files, but spend very few time on this.
> 
> Thanks,
> Jianfeng