From patchwork Tue Mar 5 10:30:00 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Borntraeger X-Patchwork-Id: 10839243 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 19D8E1575 for ; Tue, 5 Mar 2019 10:30:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 050102B9E3 for ; Tue, 5 Mar 2019 10:30:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EC9432BAA4; Tue, 5 Mar 2019 10:30:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9819A2B9C8 for ; Tue, 5 Mar 2019 10:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727159AbfCEKaL (ORCPT ); Tue, 5 Mar 2019 05:30:11 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:58478 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726190AbfCEKaK (ORCPT ); Tue, 5 Mar 2019 05:30:10 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x25APOlK086703 for ; Tue, 5 Mar 2019 05:30:09 -0500 Received: from e12.ny.us.ibm.com (e12.ny.us.ibm.com [129.33.205.202]) by mx0a-001b2d01.pphosted.com with ESMTP id 2r1pjwagd9-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 05 Mar 2019 05:30:09 -0500 Received: from localhost by e12.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 5 Mar 2019 10:30:03 -0000 Received: from b01ledav002.gho.pok.ibm.com (b01ledav002.gho.pok.ibm.com [9.57.199.107]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x25AU27320971560 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 5 Mar 2019 10:30:02 GMT Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A607312405E; Tue, 5 Mar 2019 10:30:02 +0000 (GMT) Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 892F2124055; Tue, 5 Mar 2019 10:30:02 +0000 (GMT) Received: from localhost.localdomain (unknown [9.114.17.106]) by b01ledav002.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 5 Mar 2019 10:30:02 +0000 (GMT) From: Christian Borntraeger To: Janosch Frank Cc: KVM , Cornelia Huck , Christian Borntraeger , David Hildenbrand , Joerg Roedel , Christoffer Dall , Marc Zyngier , James Hogan , Paul Mackerras , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Subject: [PATCH 0/2] disabling halt polling for nested virtualization Date: Tue, 5 Mar 2019 05:30:00 -0500 X-Mailer: git-send-email 2.17.1 X-TM-AS-GCONF: 00 x-cbid: 19030510-0060-0000-0000-00000316EF5C X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010708; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000281; SDB=6.01169909; UDB=6.00611388; IPR=6.00950543; MB=3.00025838; MTD=3.00000008; XFM=3.00000015; UTC=2019-03-05 10:30:06 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19030510-0061-0000-0000-000048825293 Message-Id: <20190305103002.5801-1-borntraeger@de.ibm.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-05_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=379 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903050074 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Folks, this is a very simple variant to disable halt polling when the KVM host is already running virtualized. We could imagine more complex variants (like tuning down the halt polling value) but this seems to do the trick for some kvm deployment scenarios on s390x. (e.g. having multiple LPARS with KVMs that are in itself already overcommitted). This still needs tuning and the right default value, but I want to start the discussion. Christian Borntraeger (2): KVM: polling: add architecture backend to disable polling KVM: s390: provide kvm_arch_no_poll function arch/s390/include/asm/kvm_host.h | 6 ++++++ arch/s390/kvm/Kconfig | 1 + include/linux/kvm_host.h | 10 ++++++++++ virt/kvm/Kconfig | 3 +++ virt/kvm/kvm_main.c | 2 +- 5 files changed, 21 insertions(+), 1 deletion(-) Acked-by: Paolo Bonzini