From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752611AbcGYJRn (ORCPT ); Mon, 25 Jul 2016 05:17:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44947 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751805AbcGYJRe (ORCPT ); Mon, 25 Jul 2016 05:17:34 -0400 From: Vitaly Kuznetsov To: David Vrabel , Boris Ostrovsky Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Stefano Stabellini , xen-devel@lists.xenproject.org, Juergen Gross , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Jan Beulich" , Andrew Cooper Subject: Re: [PATCH linux v2 0/9] xen: pvhvm: support bootup on secondary vCPUs References: <1467302203-22399-1-git-send-email-vkuznets@redhat.com> Date: Mon, 25 Jul 2016 11:17:30 +0200 In-Reply-To: <1467302203-22399-1-git-send-email-vkuznets@redhat.com> (Vitaly Kuznetsov's message of "Thu, 30 Jun 2016 17:56:34 +0200") Message-ID: <87vazuvzyt.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.95 (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 [10.5.110.32]); Mon, 25 Jul 2016 09:17:34 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vitaly Kuznetsov writes: > 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. > > This series solves the issue for x86 PVHVM guests. PV guests don't (and > probably won't) support kdump so I always assume Xen's vCPU id == Linux's > vCPU id. ARM guests will probably need to get proper mapping once we start > supporting kexec/kdump there. > > Changes since v1: > - "x86/acpi: store ACPI ids from MADT for future usage" patch added. > - Use ACPI ids instead of vLAPIC ids/2 [Andrew Cooper, Jan Beulich] > - Introduce xen_vcpu_nr() helper [David Vrabel]. > - Modify all callers of HYPERVISOR_vcpu_op() instead of modifying > HYPERVISOR_vcpu_op() [David Vrabel] David, Boris, I didn't get any feedback for the v2 of this patchset, is it ready to go in for 4.8 or is there anything else I need to do to make this happen? BTW, the patch describing the de facto "ACPI id == Xen's VCPU id" policy is in xen.git: commit ea210c52abb6458e39f5365f7f2c3abb9c191c47 Author: Vitaly Kuznetsov Date: Tue Jul 12 13:44:42 2016 +0200 x86, hvm: document the de facto policy for vCPU ids Thanks, -- Vitaly