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=-8.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E2229C433E6 for ; Wed, 3 Feb 2021 12:41:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91CD664F9A for ; Wed, 3 Feb 2021 12:41:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230355AbhBCMlg (ORCPT ); Wed, 3 Feb 2021 07:41:36 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58524 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229691AbhBCMl1 (ORCPT ); Wed, 3 Feb 2021 07:41:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612355998; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mXIEHt/+ZImaha+lRwXZShNsH0YZB0lQG8cbY1aYCEA=; b=Vr3Z+StNSdVpa0QwRpYwVrY3MNdhqpxmTjV8/AcAye3pXcH7z4jMWuEVjebDR1PRtoVSu9 7JzogTFRShOSNsTN7BNpHiRMQAiRt6Ocge17/ClPT0BBYwiAWYxlB/vxS4oF15E2zF7Sgm 8UoBF/iHfDkn7Gy3KZCZYUKo3Qa+sHw= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-491-h9ppxdDGOIycs1qeStd9wQ-1; Wed, 03 Feb 2021 07:39:56 -0500 X-MC-Unique: h9ppxdDGOIycs1qeStd9wQ-1 Received: by mail-ej1-f70.google.com with SMTP id k3so11878876ejr.16 for ; Wed, 03 Feb 2021 04:39:56 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=mXIEHt/+ZImaha+lRwXZShNsH0YZB0lQG8cbY1aYCEA=; b=TYUWhWDVMpmUI9frkXpJnDMRZOxIj/aMVpshWGaaJk5IYcxZ6o8bQSppbmTcHqa3JE Sws/yb12+eyIuFxYCHWqBl9MQt6615fatx/rYArSZmkee2sVpfmTM988/6BCXMNGNsIw nLgGgR84974Tb4rMdgT0eB9+vEbB08TfWMi9lme7nvl4Ot9ybbLNnBkEmjVrHsaiNP5C Vb2Red4t1aiSwwx5voy4BThw8bJVVN4wXTK87MMrUruS6lSLXi9GHG5E6jpY6rtMNwKe I+pT6q0Fnir4BcQG9Y/Qh7cNWviNzRVo/HvRp7JyYZYiaBRsk4vFiTKpG7RNn4104FWq Si6w== X-Gm-Message-State: AOAM533AzZz8iVCKe7JhMQfAFaO/Wvfa0CAx8DDaUIza3v5xlEiwlT5e nSrd6Btkdmn7VyKzpF43Sd9I4mTq79KR1umY9ALXj2kmzJ1L22bCPsPsUlINOpoRkUegr6P1NN/ nlCgL1qSzqvTH8E22td3IpiTJ X-Received: by 2002:a17:906:2993:: with SMTP id x19mr2816798eje.409.1612355995524; Wed, 03 Feb 2021 04:39:55 -0800 (PST) X-Google-Smtp-Source: ABdhPJyTXgGps9Cf5vzp942FAOVNGcW5hyMGurVlJU/3ZT8IdK2S9BrQGLYHWjZgagUazvZZuD63Lw== X-Received: by 2002:a17:906:2993:: with SMTP id x19mr2816786eje.409.1612355995361; Wed, 03 Feb 2021 04:39:55 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id gt18sm952486ejb.104.2021.02.03.04.39.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Feb 2021 04:39:54 -0800 (PST) To: Ben Gardon , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Peter Xu , Sean Christopherson , Peter Shier , Peter Feiner , Junaid Shahid , Jim Mattson , Yulei Zhang , Wanpeng Li , Vitaly Kuznetsov , Xiao Guangrong References: <20210202185734.1680553-1-bgardon@google.com> <20210202185734.1680553-24-bgardon@google.com> From: Paolo Bonzini Subject: Re: [PATCH v2 23/28] KVM: x86/mmu: Allow parallel page faults for the TDP MMU Message-ID: Date: Wed, 3 Feb 2021 13:39:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210202185734.1680553-24-bgardon@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/02/21 19:57, Ben Gardon wrote: > > - write_lock(&vcpu->kvm->mmu_lock); > + > + if (is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)) > + read_lock(&vcpu->kvm->mmu_lock); > + else > + write_lock(&vcpu->kvm->mmu_lock); > + I'd like to make this into two helper functions, but I'm not sure about the naming: - kvm_mmu_read_lock_for_root/kvm_mmu_read_unlock_for_root: not precise because it's really write-locked for shadow MMU roots - kvm_mmu_lock_for_root/kvm_mmu_unlock_for_root: not clear that TDP MMU operations will need to operate in shared-lock mode I prefer the first because at least it's the conservative option, but I'm open to other opinions and suggestions. Paolo