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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01A0EC433F5 for ; Sat, 7 May 2022 07:46:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1446022AbiEGHuQ (ORCPT ); Sat, 7 May 2022 03:50:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1442082AbiEGHuL (ORCPT ); Sat, 7 May 2022 03:50:11 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04EAD54BC9; Sat, 7 May 2022 00:46:26 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id x12so7889637pgj.7; Sat, 07 May 2022 00:46:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=HoNZSyMsFh0YGr6XMn2S1QvK2RQy1yb4yDnc0NWz6oc=; b=Ebb7mWsRqf/tGM07zO/HW9zZ5uDpqZ7FmKRVWRwJ5I9vjjFF1+vYkK6F4/1cru8rq7 OjRLKU4N3l9l6c5pTvoUEbItc/bQc6dGsj8uGOJAqCKhQ8KstUnZU55m0c20a7JRFn9y Y15yeYCujfL7rKv0Dpckke6FJzfSrhst7NiQpAKOsAD1rHQhvCGYgItqP9r+iKtnCzbC EHSOS18gj2ZZwOxGC2LR2VcyNibP3U8o8yYdyN+uPA0o9UfdXr+zLOcUPzVstYe1BBXZ zmk7NtWev27+5si9mgOUUMT/1xO1XsYg5DVZHVUSZ2pNAqTNHSOeMttvKZv4e9UzP3eX 4ssg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=HoNZSyMsFh0YGr6XMn2S1QvK2RQy1yb4yDnc0NWz6oc=; b=2kz5fuaS3dVhXQ4/Q9IGRP0mW6s9vimaASb4sQ/a66+zy+IzbT0PtlY6PdmmMTsnzq nt5JcAyxiEkUPp9zcOoKMgfJhKq33SCg7qAEQDrgMvIw5taRZd4ihWdcTCnYzeOzEH7m xbX8mKffmjrUhVMETmRKB2vCuIZ7Va5y3akHjYHnASU6zVz7AdnpVskc1dvadPT7LNi0 c2QnBAGgWrrnB69pITXKlcCvy/6DC9MswtctAicI8xlCY3v8W6/0d4YzRIYmnDNOVidh tI5ODtFA+g0cQbuN7NkGP/wBF0hUwo4bNZHo7G8I5zwHQZJXlVYdzqKi5CV0qR5RP3wu hU/g== X-Gm-Message-State: AOAM533yG4k+J/nf+2qtJ+sRVTsClF8hkDPkHC86hXpB03wBMsLCBITq QAwnp0gTpAukg0LsH38ySao= X-Google-Smtp-Source: ABdhPJxjguZ9DDrPz4gDnb9yHPkMUMCF3GCbvbp/S7EovieX143wCGT1AeBuk0StNs+kplE5MiMg0Q== X-Received: by 2002:a05:6a00:130e:b0:4cc:3c7d:4dec with SMTP id j14-20020a056a00130e00b004cc3c7d4decmr7398006pfu.32.1651909585489; Sat, 07 May 2022 00:46:25 -0700 (PDT) Received: from [30.22.112.212] ([205.204.117.91]) by smtp.gmail.com with ESMTPSA id u18-20020a170902e21200b0015e8d4eb283sm2990078plb.205.2022.05.07.00.46.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 07 May 2022 00:46:25 -0700 (PDT) Message-ID: Date: Sat, 7 May 2022 15:46:19 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v4 01/20] KVM: x86/mmu: Optimize MMU page cache lookup for all direct SPs Content-Language: en-US To: David Matlack , Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner References: <20220422210546.458943-1-dmatlack@google.com> <20220422210546.458943-2-dmatlack@google.com> From: Lai Jiangshan In-Reply-To: <20220422210546.458943-2-dmatlack@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On 2022/4/23 05:05, David Matlack wrote: > Commit fb58a9c345f6 ("KVM: x86/mmu: Optimize MMU page cache lookup for > fully direct MMUs") skipped the unsync checks and write flood clearing > for full direct MMUs. We can extend this further to skip the checks for > all direct shadow pages. Direct shadow pages in indirect MMUs (i.e. > shadow paging) are used when shadowing a guest huge page with smaller > pages. Such direct shadow pages, like their counterparts in fully direct > MMUs, are never marked unsynced or have a non-zero write-flooding count. > > Checking sp->role.direct also generates better code than checking > direct_map because, due to register pressure, direct_map has to get > shoved onto the stack and then pulled back off. > > No functional change intended. > > Reviewed-by: Sean Christopherson > Reviewed-by: Peter Xu > Signed-off-by: David Matlack Reviewed-by: Lai Jiangshan