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 6D23AC433B4 for ; Fri, 7 May 2021 08:28:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3351D61456 for ; Fri, 7 May 2021 08:28:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234827AbhEGI32 (ORCPT ); Fri, 7 May 2021 04:29:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:42554 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236232AbhEGI3Q (ORCPT ); Fri, 7 May 2021 04:29:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620376096; 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=Sfld2vV917cyiL2EAlelGukfSqp0YsFFbFT8fUGg2a0=; b=L+47zos/AElokN9Ftr7XK1HhTPyycpEYZPKQr26LaLLkBtt8boquSySrmNBRO48iRkx1yc czB7hItAPhoopX9QHAZ0puER5BxGVpf2BUBI4dlA3QqgF5wDV0GDqmhx5rp/LUgXCUeQDW fs0uf6BsKfSRf3VxbUExHTpzCv1SgEo= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-187-rdchX2D-O_uAfWxQbo7Bgw-1; Fri, 07 May 2021 04:28:15 -0400 X-MC-Unique: rdchX2D-O_uAfWxQbo7Bgw-1 Received: by mail-wm1-f69.google.com with SMTP id g17-20020a05600c0011b029014399f816a3so1974432wmc.7 for ; Fri, 07 May 2021 01:28:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Sfld2vV917cyiL2EAlelGukfSqp0YsFFbFT8fUGg2a0=; b=ASj/gmtGYOAQOo2epHg1JabMocS9u2El7VbrLMltdioZO0DwdW6UFoL70KWvU/U7em Q7jeEokMYlpFBqHor5yjuYh/OPGOwpnU508KH1orewdLOy4ywRGXRCRWpNGDexEOzBAy YthpSoM1+5ud3353hguPj11L5vLzub65HaDSVCPB8ocsfJG6IoMccQEmhmDJgT2Xpk+L iNMDpLutwk0l3niScpiwlEd4NF99jlWXvBqSwT0B8Q4PqfD4QMDMloPsmT3XlgEPMur2 DkAU3bjDRPrI5dIvVVakF+COMrxmVRTNKzsQ5UUs3lVk3EWRwQmxZqPc4JoRpxz24uRD NlOA== X-Gm-Message-State: AOAM531XPORjlluQ1BKvygW8mjrqSnj6nJmj5siUtJ6O9WaHyJl5zRjV gtFVnyknkJIHuHCwMZw34o25Wt604OSV/DkZdfP6sXBSAnUlxWiFHkardEYySBRgvWlsKuSHfDC 39z7jr3Ay2uZWRBhgYbohSvcb X-Received: by 2002:a7b:c041:: with SMTP id u1mr8462319wmc.95.1620376093992; Fri, 07 May 2021 01:28:13 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyFMKYgRXib25C3Lc2510yNv1ITx4PyXpJJlV7RmQiTCU87SAb5qiOV0noF60PFofX3S2ne0A== X-Received: by 2002:a7b:c041:: with SMTP id u1mr8462299wmc.95.1620376093797; Fri, 07 May 2021 01:28:13 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e? ([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id m7sm8031229wrv.35.2021.05.07.01.28.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 07 May 2021 01:28:13 -0700 (PDT) Subject: Re: [PATCH v3 8/8] KVM: x86/mmu: Lazily allocate memslot rmaps To: Ben Gardon , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Peter Xu , Sean Christopherson , Peter Shier , Yulei Zhang , Wanpeng Li , Xiao Guangrong , Kai Huang , Keqian Zhu References: <20210506184241.618958-1-bgardon@google.com> <20210506184241.618958-9-bgardon@google.com> From: Paolo Bonzini Message-ID: Date: Fri, 7 May 2021 10:28:11 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210506184241.618958-9-bgardon@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/05/21 20:42, Ben Gardon wrote: > + /* > + * memslots_have_rmaps is set and read in different lock contexts, > + * so protect it with smp_load/store. > + */ > + smp_store_release(&kvm->arch.memslots_have_rmaps, true); Shorter and better: /* write rmap pointers before memslots_have_rmaps */ > + mutex_unlock(&kvm->slots_arch_lock); > + return 0; > +} > + > bool kvm_memslots_have_rmaps(struct kvm *kvm) > { > - return kvm->arch.memslots_have_rmaps; > + /* > + * memslots_have_rmaps is set and read in different lock contexts, > + * so protect it with smp_load/store. > + */ > + return smp_load_acquire(&kvm->arch.memslots_have_rmaps); > } > Likewise, /* read memslots_have_rmaps before the rmaps themselves */ Paolo