From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vitaly Kuznetsov Subject: Re: support for more than 32 VCPUs when migrating PVHVM guest Date: Mon, 02 Feb 2015 12:03:28 +0100 Message-ID: <8761bkwp6n.fsf@vitty.brq.redhat.com> References: <87k300wpwj.fsf@vitty.brq.redhat.com> <54CF5838.5020007@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1YIEn9-0002fJ-Ad for xen-devel@lists.xenproject.org; Mon, 02 Feb 2015 11:03:43 +0000 In-Reply-To: <54CF5838.5020007@citrix.com> (Andrew Cooper's message of "Mon, 2 Feb 2015 10:58:00 +0000") List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andrew Cooper Cc: xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org Andrew Cooper writes: > On 02/02/15 10:47, Vitaly Kuznetsov wrote: >> Hi Konrad, >> >> I just hit an issue with PVHVM guests after save/restore (or migration), >> if a PVHVM guest has > 32 VCPUs it hangs. Turns out, you saw it almost a >> year ago and even wrote patches to call VCPUOP_register_vcpu_info after >> resume. Unfortunately these patches never made it to xen/kernel. Do you >> have a plan to pick this up? What were the arguments against your >> suggestion? > > 32 VCPUs is the legacy limit for HVM guests, but should not have any > remaining artefacts these days. > > Do you know why the hang occurs? I can't spot anything in the legacy > migration code which would enforce such a limit. > > What is the subject of the thread you reference so I can search for it? > Sorry, I should have send the link: http://lists.xen.org/archives/html/xen-devel/2014-04/msg00794.html Konrad's patches: http://lists.xen.org/archives/html/xen-devel/2014-04/msg01199.html The issue is that we don't call VCPUOP_register_vcpu_info after suspend/resume (or migration) and it is mandatory. -- Vitaly