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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 C1491C55186 for ; Fri, 24 Apr 2020 20:59:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9EF5D215A4 for ; Fri, 24 Apr 2020 20:59:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Njqlt8b8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726591AbgDXU7x (ORCPT ); Fri, 24 Apr 2020 16:59:53 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:57889 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726554AbgDXU7u (ORCPT ); Fri, 24 Apr 2020 16:59:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587761988; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=U9IoMv2MqMZRTKXdsbx7ye5WORGaUC+vYyvm1coX4f0=; b=Njqlt8b8N6Y6E8ixETPrnzvq9J/z943FNhzb9yS6TNRHeBpZNKThZPzlXp+D7aqVGyLozG wXDJMXw0ZV/sCnS57DtIzKjYrMYwJaYsEbZd22x4l/YxTRX3K2G0qbklx6T8k/RFTLZTHo DJzPjBdPl3FO2aCLJ7MVNkmacy124B0= Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-254-eqojTyfkM_y3vKpfjTi1CA-1; Fri, 24 Apr 2020 16:59:46 -0400 X-MC-Unique: eqojTyfkM_y3vKpfjTi1CA-1 Received: by mail-qt1-f199.google.com with SMTP id y31so12410230qta.16 for ; Fri, 24 Apr 2020 13:59:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=U9IoMv2MqMZRTKXdsbx7ye5WORGaUC+vYyvm1coX4f0=; b=klgr2vWd1MI2zFB0S7nCUeQavutsnzR/0cNAWCviAzmuXMJhSbpmiQNYD+uP1U4Q4A 8Q8scrmaMGVOeex8LyQ21glD03WmQ7VZN7LelH98D8P28XSyT5sG7lGQqP7lTybOmxZ/ HO+fsf9kQZoEnxvnFAOjLtqXzXjkXxbgFNagQoelZd6wHCnXP/vIKhvKz6Wh7qGpQQyJ Knm6Ssbjm0GY/gAGNN8oh9icH1ujz5VrO79mbJ+OSawlug8mDPMDE2wW+SQyQv9qUUkv HQt7mLzIT3djsW7fcINKh280hx2vF47htOCNp15UdFJbEY7B1Lym88W4w9qgQskW6ECf f5YQ== X-Gm-Message-State: AGi0PuaMEWa8UTLbIA529tyk9WpFUhIqvIXgC290TljGchHMgJ2rBZIG aU9IltVB2VOtckQQVc1sk5tqAFr79My5+jO1zloyBH1v6tF5W4OTO22G09glaYWSTTtYmyaqOb0 JZT+vyyWr5Yt6KTBPkga2fdIe X-Received: by 2002:aed:2450:: with SMTP id s16mr11331243qtc.345.1587761986459; Fri, 24 Apr 2020 13:59:46 -0700 (PDT) X-Google-Smtp-Source: APiQypKJZaA2jJePTA2AJiGob94NbVuTTBF4yDeyKSdTk01eGX6a1DAQRmHqIRCrGVJAATKqX19Jbg== X-Received: by 2002:aed:2450:: with SMTP id s16mr11331227qtc.345.1587761986098; Fri, 24 Apr 2020 13:59:46 -0700 (PDT) Received: from xz-x1 ([2607:9880:19c0:32::2]) by smtp.gmail.com with ESMTPSA id c33sm4927700qtb.76.2020.04.24.13.59.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Apr 2020 13:59:45 -0700 (PDT) Date: Fri, 24 Apr 2020 16:59:38 -0400 From: Peter Xu To: Sean Christopherson Cc: Xiaoyao Li , Paolo Bonzini , kvm@vger.kernel.org, Nadav Amit , Vitaly Kuznetsov , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 1/3] kvm: x86: Rename KVM_DEBUGREG_RELOAD to KVM_DEBUGREG_NEED_RELOAD Message-ID: <20200424205938.GB48376@xz-x1> References: <20200416101509.73526-1-xiaoyao.li@intel.com> <20200416101509.73526-2-xiaoyao.li@intel.com> <20200423190941.GN17824@linux.intel.com> <20200424202103.GA48376@xz-x1> <20200424202921.GG30013@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200424202921.GG30013@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 24, 2020 at 01:29:22PM -0700, Sean Christopherson wrote: > On Fri, Apr 24, 2020 at 04:21:03PM -0400, Peter Xu wrote: > > On Thu, Apr 23, 2020 at 12:09:42PM -0700, Sean Christopherson wrote: > > > On Thu, Apr 16, 2020 at 06:15:07PM +0800, Xiaoyao Li wrote: > > > > To make it more clear that the flag means DRn (except DR7) need to be > > > > reloaded before vm entry. > > > > > > > > Signed-off-by: Xiaoyao Li > > > > --- > > > > arch/x86/include/asm/kvm_host.h | 2 +- > > > > arch/x86/kvm/x86.c | 6 +++--- > > > > 2 files changed, 4 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > > > > index c7da23aed79a..f465c76e6e5a 100644 > > > > --- a/arch/x86/include/asm/kvm_host.h > > > > +++ b/arch/x86/include/asm/kvm_host.h > > > > @@ -511,7 +511,7 @@ struct kvm_pmu_ops; > > > > enum { > > > > KVM_DEBUGREG_BP_ENABLED = 1, > > > > KVM_DEBUGREG_WONT_EXIT = 2, > > > > - KVM_DEBUGREG_RELOAD = 4, > > > > + KVM_DEBUGREG_NEED_RELOAD = 4, > > > > > > My vote would be for KVM_DEBUGREG_DIRTY Any bit that is set switch_db_regs > > > triggers a reload, whereas I would expect a RELOAD flag to be set _every_ > > > time a load is needed and thus be the only bit that's checked > > > > But then shouldn't DIRTY be set as long as KVM_DEBUGREG_BP_ENABLED is set every > > time before vmenter? Then it'll somehow go back to switch_db_regs, iiuc... > > > > IIUC RELOAD actually wants to say "reload only for this iteration", that's why > > it's cleared after each reload. So maybe... RELOAD_ONCE? > > Or FORCE_LOAD, or FORCE_RELOAD? Those crossed my mind as well. Yep, FORCE_RELOAD sounds better than DIRTY. > > > (Btw, do we have debug regs tests somewhere no matter inside guest or with > > KVM_SET_GUEST_DEBUG?) > > I don't think so? OK, I'll see whether I can write some up. Thanks, -- Peter Xu