From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: Xen 4.2 and PCI hotplug. Date: Wed, 19 Dec 2012 14:36:24 +0000 Message-ID: <50D1D0E8.7050203@citrix.com> References: <20121218224606.GA6918@phenom.dumpdata.com> <50D18D4E02000078000B15B3@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 19/12/2012 09:14, Zhang, Xiantao wrote: >> -----Original Message----- >> From: Jan Beulich [mailto:JBeulich@suse.com] >> Sent: Wednesday, December 19, 2012 4:48 PM >> To: Zhang, Xiantao >> Cc: Konrad Rzeszutek Wilk; xen-devel >> Subject: Re: [Xen-devel] Xen 4.2 and PCI hotplug. >> >>>>> On 19.12.12 at 09:13, "Zhang, Xiantao" >> wrote: >>> Are you playing with Xen ? so far, Xen doesn't support PCIe device >>> hot-plug feature yet. >> When saying Xen, I assume you mean the pv-ops kernel instead? So far I was >> under the impression that this worked even with the very old 2.6.18 tree (as >> much or as little as hotplug there worked in the native case). And given that >> there are no special requirements on the hypervisor to make this work, it's >> not even obvious to me what would be missing in the pv-ops kernel to make >> it work. > Oh, my fault! Perhaps we don't need to do anything for pv-ops kernel to support device hot-plug if native system has it supported. Actually, we didn't do such testings before, since it is a native feature, not a Xen-specific one. > Xiantao My current understanding is that on boot, Xen scans the PCI bus, then dom0 rescans it later. If a hotplug event gets serviced by dom0, does there not need to be some hypercall informing Xen that a new device has appeared? I expect PCIPassthrough would not work correctly on a hotplugged device which Xen is unaware of. (But if I have got the wrong end of the stick, or this mechanism already exist, please ignore me. It just strikes me as a little xen-specific, even if the bulk of it is native) ~Andrew > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel