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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 6121DC352AA for ; Tue, 1 Oct 2019 08:39:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 439AD215EA for ; Tue, 1 Oct 2019 08:39:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729407AbfJAIjJ (ORCPT ); Tue, 1 Oct 2019 04:39:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62806 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727274AbfJAIjJ (ORCPT ); Tue, 1 Oct 2019 04:39:09 -0400 Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8FEF188302 for ; Tue, 1 Oct 2019 08:39:08 +0000 (UTC) Received: by mail-wr1-f71.google.com with SMTP id a15so5714503wrq.4 for ; Tue, 01 Oct 2019 01:39:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=V0oWnMG5UzeuD4QEm5neHsBPW9FV4K2Mbr76uGM5/zI=; b=EeSn2yQHuMSccWh+e5ERTIk4TR6CDgAXq5/o9aVt8j1Vbv5vq6qpESqs+01cktyEgA Deg5XbB1TQAuJx62vDQpGStpQiwS44Zm0m//QBORMRI8zTYzNayr0661dnb6nzl734g1 NAMz2MkW/Sd6Hm2g0pcwzLhyWhmcsUcY/ptv5LqyQofcVFTTBBzVDcIudJFeh4DmI5n0 WHWYIMqmpOOdL5rcsot6WRTD/ALmoN4iJeJymyO6O58ZPriXiGkAWnBUZAzzGQS0RsDv 7WH9p0tavn1V9Ih3xEPpG/cdEw+cm7DSIVGerzLMX2kJTNKFtBQ7Q1ds5zfVZjqz+tFt BoHw== X-Gm-Message-State: APjAAAWEhSucRW25CLQCa6Mql0RJsZ7BkpflmGPUnaZ+nEZPTAI4FDcl tCWmda2CVF7x9dc46TGqW0oGCGzba9/C+0aFokF9ky/AxgsSFOigaVYaSKmHpmrfgkMTotIVfxx xGuVTZDdpb3d7EbblgV6qZUfK X-Received: by 2002:adf:94c2:: with SMTP id 60mr1392650wrr.357.1569919146899; Tue, 01 Oct 2019 01:39:06 -0700 (PDT) X-Google-Smtp-Source: APXvYqyQkp8qJFCtpc/jzZ7GBhcO9xjJt5CEQmZ7NIVGjuCO/nB4ek1cLFqBaknBX+bsLTR5KpD9bA== X-Received: by 2002:adf:94c2:: with SMTP id 60mr1392632wrr.357.1569919146650; Tue, 01 Oct 2019 01:39:06 -0700 (PDT) Received: from vitty.brq.redhat.com (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id w12sm24653712wrg.47.2019.10.01.01.39.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Oct 2019 01:39:05 -0700 (PDT) From: Vitaly Kuznetsov To: Zhenzhong Duan , linux-kernel@vger.kernel.org Cc: Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Paolo Bonzini , Radim Krcmar , Sean Christopherson , Wanpeng Li , Jim Mattson , Joerg Roedel , Peter Zijlstra , Will Deacon Subject: Re: [PATCH 1/3] KVM: X86: Add "nopvspin" parameter to disable PV spinlocks In-Reply-To: References: <1569759666-26904-1-git-send-email-zhenzhong.duan@oracle.com> <1569759666-26904-2-git-send-email-zhenzhong.duan@oracle.com> <87pnjh3i6i.fsf@vitty.brq.redhat.com> Date: Tue, 01 Oct 2019 10:39:05 +0200 Message-ID: <87eezw3lna.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Zhenzhong Duan writes: > On 2019/9/30 23:41, Vitaly Kuznetsov wrote: >> Zhenzhong Duan writes: >> >>> There are cases where a guest tries to switch spinlocks to bare metal >>> behavior (e.g. by setting "xen_nopvspin" on XEN platform and >>> "hv_nopvspin" on HYPER_V). >>> >>> That feature is missed on KVM, add a new parameter "nopvspin" to disable >>> PV spinlocks for KVM guest. >>> >>> This new parameter is also intended to replace "xen_nopvspin" and >>> "hv_nopvspin" in the future. >> Any reason to not do it right now? We will probably need to have compat >> code to support xen_nopvspin/hv_nopvspin too but emit a 'is deprecated' >> warning. > > Sorry the description isn't clear, I'll fix it. > > I did the compat work in the other two patches. > [PATCH 2/3] xen: Mark "xen_nopvspin" parameter obsolete and map it to "nopvspin" > [PATCH 3/3] x86/hyperv: Mark "hv_nopvspin" parameter obsolete and map it to "nopvspin" > For some reason I got CCed only on the first one and moreover, I don't see e.g PATCH3 on 'linux-hyperv' mailing list. >> >>> The global variable pvspin isn't defined as __initdata as it's used at >>> runtime by XEN guest. >>> >>> Refactor the print stuff with pr_* which is preferred. >> Please do it in a separate patch. > > Ok, I'll do that in v2. Thanks for review. Thanks! -- Vitaly