From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: how to properly reset event channel in PVonHVM after kexec boot Date: Wed, 14 Mar 2012 12:05:24 +0100 Message-ID: <20120314110524.GA25099@aepfle.de> References: <20120314105254.GA21259@aepfle.de> <1331722619.23971.397.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1331722619.23971.397.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On Wed, Mar 14, Ian Campbell wrote: > On Wed, 2012-03-14 at 10:52 +0000, Olaf Hering wrote: > > What is the best way to reset all registered event channels after an > > kexec boot in a PVonHVM guest? Right now repeated kexec boots will fail > > after 1300 iterations because no more event channels can be registered. > > > > EVTCHNOP_reset can not be used because it expects the domid, which the guest > > does not know. > > It appears that it accepts DOMID_SELF. It calls > rcu_lock_target_domain_by_id which handles it explicitly. Oh, I will see how it works then. It was not obvious to me that DOMID_SELF is handled. >>From reading the code it appears that it could also reset EVTCHNSTAT_interdomain, which would hang the guest. Thats why my patch skips this state. Olaf