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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 2AB85C433DB for ; Mon, 15 Mar 2021 09:41:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAAC864DFD for ; Mon, 15 Mar 2021 09:41:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229699AbhCOJkf (ORCPT ); Mon, 15 Mar 2021 05:40:35 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:24171 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbhCOJk3 (ORCPT ); Mon, 15 Mar 2021 05:40:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615801228; h=from:from:reply-to: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=WIA9uAdrAsc0WNE5pHXgO80SUEbsiEpbQtctUapRlUU=; b=NFnIoPSHCJqB6nGFxA4BlPzi6uNdToLLZhE87/1KUjCtYvjE4BeM7ybtZgN8G9HraaDrHN juxbgCSM7X1gwVmi3qx7Il92jfyCuqGYPKKNDx/ptaO/pK0wiDkOYdN5Z95YIQoTzidZBW NzwzMBasIP/PBE7BJ/bZ0loMY7zwV1E= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-9-npB8E8JqPrW9mu9ad9xpXA-1; Mon, 15 Mar 2021 05:40:24 -0400 X-MC-Unique: npB8E8JqPrW9mu9ad9xpXA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 682228710F1; Mon, 15 Mar 2021 09:40:22 +0000 (UTC) Received: from [10.64.54.175] (vpn2-54-175.bne.redhat.com [10.64.54.175]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B66F6627DD; Mon, 15 Mar 2021 09:40:19 +0000 (UTC) Reply-To: Gavin Shan Subject: Re: [PATCH 2/4] KVM: arm64: Use find_vma_intersection() To: Marc Zyngier Cc: kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, will@kernel.org, alexandru.elisei@arm.com, shan.gavin@gmail.com References: <20210315041844.64915-1-gshan@redhat.com> <20210315041844.64915-3-gshan@redhat.com> <87eeggg5nt.wl-maz@kernel.org> From: Gavin Shan Message-ID: <86cd410a-d62c-9023-7371-a9d178bfafc1@redhat.com> Date: Mon, 15 Mar 2021 20:40:16 +1100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <87eeggg5nt.wl-maz@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marc, On 3/15/21 7:52 PM, Marc Zyngier wrote: > On Mon, 15 Mar 2021 04:18:42 +0000, > Gavin Shan wrote: >> >> find_vma_intersection() has been existing to search the intersected >> vma. This uses the function where it's applicable, to simplify the >> code. >> >> Signed-off-by: Gavin Shan >> --- >> arch/arm64/kvm/mmu.c | 10 ++++++---- >> 1 file changed, 6 insertions(+), 4 deletions(-) >> >> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c >> index 84e70f953de6..286b603ed0d3 100644 >> --- a/arch/arm64/kvm/mmu.c >> +++ b/arch/arm64/kvm/mmu.c >> @@ -421,10 +421,11 @@ static void stage2_unmap_memslot(struct kvm *kvm, >> * +--------------------------------------------+ >> */ >> do { >> - struct vm_area_struct *vma = find_vma(current->mm, hva); >> + struct vm_area_struct *vma; >> hva_t vm_start, vm_end; >> >> - if (!vma || vma->vm_start >= reg_end) >> + vma = find_vma_intersection(current->mm, hva, reg_end); > > For context, here's the definition of find_vma_intersection(): > > > static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr) > { > struct vm_area_struct * vma = find_vma(mm,start_addr); > > if (vma && end_addr <= vma->vm_start) > vma = NULL; > return vma; > } > > > It seems that there is a boundary issue in either the old code or the > new one in the case where (reg_end == vma->start). > > Which one is which? > The old and new code is interchangeable, meaning "reg_end == vma->start" is invalid in both cases. So if there is a boundary issue, the old and new code should have same issue. According to the code, "reg_end == vma->start" is invalid. So I don't see there is a boundary issue. Hopefully, I don't miss anything :) Thanks, Gavin