From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932101AbcF2JRH (ORCPT ); Wed, 29 Jun 2016 05:17:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42422 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751997AbcF2JRA (ORCPT ); Wed, 29 Jun 2016 05:17:00 -0400 From: Vitaly Kuznetsov To: David Vrabel Cc: , , , Stefano Stabellini , Boris Ostrovsky , Juergen Gross , Thomas Gleixner , "Ingo Molnar" , "H. Peter Anvin" , Julien Grall Subject: Re: [PATCH linux 0/8] xen: pvhvm: support bootup on secondary vCPUs References: <1467132449-1030-1-git-send-email-vkuznets@redhat.com> <5772B4C2.4010906@citrix.com> Date: Wed, 29 Jun 2016 11:16:55 +0200 In-Reply-To: <5772B4C2.4010906@citrix.com> (David Vrabel's message of "Tue, 28 Jun 2016 18:32:50 +0100") Message-ID: <871t3gwe0o.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 29 Jun 2016 09:16:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org David Vrabel writes: > On 28/06/16 17:47, Vitaly Kuznetsov wrote: >> It may happen that Xen's and Linux's ideas of vCPU id diverge. In >> particular, when we crash on a secondary vCPU we may want to do kdump >> and unlike plain kexec where we do migrate_to_reboot_cpu() we try booting >> on the vCPU which crashed. This doesn't work very well for PVHVM guests as >> we have a number of hypercalls where we pass vCPU id as a parameter. These >> hypercalls either fail or do something unexpected. To solve the issue we >> need to have a mapping between Linux's and Xen's vCPU ids. > > Could the soft-reboot hypercall (optionally) return on vcpu 0? > In theory, yes, I think we can re-arrange vCPUs inside the hypervisor so Linux will get them in the natural order after soft reset. -- Vitaly