From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17305C04AB6 for ; Tue, 28 May 2019 12:53:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2E8C2081C for ; Tue, 28 May 2019 12:53:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727229AbfE1Mxu (ORCPT ); Tue, 28 May 2019 08:53:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726620AbfE1Mxt (ORCPT ); Tue, 28 May 2019 08:53:49 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 84CE8A3B6C; Tue, 28 May 2019 12:53:49 +0000 (UTC) Received: from gondolin (dhcp-192-222.str.redhat.com [10.33.192.222]) by smtp.corp.redhat.com (Postfix) with ESMTP id 85B2B1972C; Tue, 28 May 2019 12:53:47 +0000 (UTC) Date: Tue, 28 May 2019 14:53:44 +0200 From: Cornelia Huck To: Christian Borntraeger Cc: Janosch Frank , Paolo Bonzini , Radim =?UTF-8?B?S3LEjW3DocWZ?= , Thomas Huth , kvm@vger.kernel.org, Shuah Khan , David Hildenbrand , Andrew Jones , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH 8/9] KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID Message-ID: <20190528145344.42fe6bc5.cohuck@redhat.com> In-Reply-To: <1deb73ac-9589-89cb-9a9b-f9957584733e@de.ibm.com> References: <20190523164309.13345-1-thuth@redhat.com> <20190523164309.13345-9-thuth@redhat.com> <1deb73ac-9589-89cb-9a9b-f9957584733e@de.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 28 May 2019 12:53:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 28 May 2019 13:00:30 +0200 Christian Borntraeger wrote: > Paolo, Radim, > > would you consider this patch (or the full series) as 5.2 material or 5.3 material? FWIW, I'd consider this patch 5.2 material, as we're currently relaying wrong values to userspace. > > > On 23.05.19 18:43, Thomas Huth wrote: > > KVM_CAP_MAX_VCPU_ID is currently always reporting KVM_MAX_VCPU_ID on all > > architectures. However, on s390x, the amount of usable CPUs is determined > > during runtime - it is depending on the features of the machine the code > > is running on. Since we are using the vcpu_id as an index into the SCA > > structures that are defined by the hardware (see e.g. the sca_add_vcpu() > > function), it is not only the amount of CPUs that is limited by the hard- > > ware, but also the range of IDs that we can use. > > Thus KVM_CAP_MAX_VCPU_ID must be determined during runtime on s390x, too. > > So the handling of KVM_CAP_MAX_VCPU_ID has to be moved from the common > > code into the architecture specific code, and on s390x we have to return > > the same value here as for KVM_CAP_MAX_VCPUS. > > This problem has been discovered with the kvm_create_max_vcpus selftest. > > With this change applied, the selftest now passes on s390x, too. > > > > Signed-off-by: Thomas Huth > > --- > > arch/mips/kvm/mips.c | 3 +++ > > arch/powerpc/kvm/powerpc.c | 3 +++ > > arch/s390/kvm/kvm-s390.c | 1 + > > arch/x86/kvm/x86.c | 3 +++ > > virt/kvm/arm/arm.c | 3 +++ > > virt/kvm/kvm_main.c | 2 -- > > 6 files changed, 13 insertions(+), 2 deletions(-)