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=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 358F7C43387 for ; Mon, 7 Jan 2019 16:26:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED5D92183F for ; Mon, 7 Jan 2019 16:26:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SweO434i" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730376AbfAGQ0o (ORCPT ); Mon, 7 Jan 2019 11:26:44 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:42115 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727483AbfAGQ0o (ORCPT ); Mon, 7 Jan 2019 11:26:44 -0500 Received: by mail-wr1-f67.google.com with SMTP id q18so1029557wrx.9; Mon, 07 Jan 2019 08:26:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:openpgp:autocrypt:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=/U70qfKIXZfDtiR8L8OsjRjbuUkYcPLUD/fleteotXk=; b=SweO434iWDy1IdSqUunohVYNhyzYgiE2pEiHkiqxgo7qhyAtL0Eiu23Gx6vr4pdFuW sNscKecGB1c9z3VebNG+aC+0hxuHorwhJmPrT6EhjWrmjp82XsZ6lDopdKlZBzjHJqsS 906fJCHUocNRq2/jg5m0WxI+tS53UdBRhufo8nwa4J8JOrr3AfaZf7IXzPenzAGtceiz 3TDYrmSo2oDAcytg0LFTQcYFmR6ZCrvngXL8ttaxRZhEnNVCSbcrsR510lG8Cy502jPL N3DCPIbuc+8SfPLGXF1RzZd1nIQtdk0I3QRzZGjHKpZrMZfqBEXm8cDx0FjqopsTwXQh T6lg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:openpgp :autocrypt:message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=/U70qfKIXZfDtiR8L8OsjRjbuUkYcPLUD/fleteotXk=; b=ZJgT5Jyks6xpCDJJfQ37vDHjTq5vhW1ZqpzL3vWgJLhr1gbzcMn/gykNT0KyAMk5Qq B2nm6v2lVNLjE/rErZOB38iM6+SBfLd4v2+BDFsPAhBLONnyw/xlFY700omkv3ae6MhD YMKMcsJaA4BqsofFxpQEz+AgcNDudKB1cS4aaPgotbuAx15UEZAqsRnGDrPcmRfAXLzV ed3pvbyH2leTWLtC9SXusc1Ukx77/uqekccOke8h9UzpFzQDOwvxmV4U6EcOE0JPrBYC zbWHtnqzAB7cx1i6Uo2YPJRB3+q6rN/INY6fybosnVZc6SUUPKNJASxadzIepGrtG4e+ y/RA== X-Gm-Message-State: AJcUukcmfO49M6R17geXI3pb0MwJYRPhUm6MSdAb2Uag8msWGzzBtYU/ XxC5oXwQZOHVcGOQw8FPvk8= X-Google-Smtp-Source: ALg8bN53Ae/LWk8R4oNfWY8JaVuQFl1l5dBEGbQBZ1oQw+MohX5T5j7ACyzpZfip9SWSnWHDOfTYEg== X-Received: by 2002:a05:6000:120a:: with SMTP id e10mr52902210wrx.85.1546878401435; Mon, 07 Jan 2019 08:26:41 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:3473:41cf:8b30:f2e1? ([2001:b07:6468:f312:3473:41cf:8b30:f2e1]) by smtp.googlemail.com with ESMTPSA id n127sm8479381wmd.20.2019.01.07.08.26.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Jan 2019 08:26:40 -0800 (PST) Subject: Re: [PATCH 9/11] KVM/MMU: Flush tlb in the kvm_mmu_write_protect_pt_masked() To: lantianyu1986@gmail.com Cc: Lan Tianyu , christoffer.dall@arm.com, marc.zyngier@arm.com, linux@armlinux.org.uk, catalin.marinas@arm.com, will.deacon@arm.com, jhogan@kernel.org, ralf@linux-mips.org, paul.burton@mips.com, paulus@ozlabs.org, benh@kernel.crashing.org, mpe@ellerman.id.au, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, michael.h.kelley@microsoft.com, kys@microsoft.com, vkuznets@redhat.com References: <20190104085405.40356-1-Tianyu.Lan@microsoft.com> <20190104085405.40356-10-Tianyu.Lan@microsoft.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20190104085405.40356-10-Tianyu.Lan@microsoft.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/01/19 09:54, lantianyu1986@gmail.com wrote: > rmap_head = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask), > PT_PAGE_TABLE_LEVEL, slot); > - __rmap_write_protect(kvm, rmap_head, false); > + flush |= __rmap_write_protect(kvm, rmap_head, false); > > /* clear the first set bit */ > mask &= mask - 1; > } > + > + if (flush && kvm_available_flush_tlb_with_range()) { > + kvm_flush_remote_tlbs_with_address(kvm, > + slot->base_gfn + gfn_offset, > + hweight_long(mask)); Mask is zero here, so this probably won't work. In addition, I suspect calling the hypercall once for every 64 pages is not very efficient. Passing a flush list into kvm_mmu_write_protect_pt_masked, and flushing in kvm_arch_mmu_enable_log_dirty_pt_masked, isn't efficient either because kvm_arch_mmu_enable_log_dirty_pt_masked is also called once per word. I don't have any good ideas, except for moving the whole kvm_clear_dirty_log_protect loop into architecture-specific code (which is not the direction we want---architectures should share more code, not less). Paolo > + flush = false; > + } > +