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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 E5C02C43381 for ; Wed, 20 Mar 2019 10:23:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEC952146E for ; Wed, 20 Mar 2019 10:23:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727245AbfCTKXr (ORCPT ); Wed, 20 Mar 2019 06:23:47 -0400 Received: from foss.arm.com ([217.140.101.70]:37654 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726006AbfCTKXr (ORCPT ); Wed, 20 Mar 2019 06:23:47 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 38DF680D; Wed, 20 Mar 2019 03:23:46 -0700 (PDT) Received: from [10.1.196.93] (en101.cambridge.arm.com [10.1.196.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 621FE3F71A; Wed, 20 Mar 2019 03:23:43 -0700 (PDT) Subject: Re: [PATCH] kvm: arm: Fix handling of stage2 huge mappings To: marc.zyngier@arm.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, will.deacon@arm.com, catalin.marinas@arm.com, james.morse@arm.com, julien.thierry@arm.com, wanghaibin.wang@huawei.com, lious.lilei@hisilicon.com, lishuo1@hisilicon.com, zhengxiang9@huawei.com, yuzenghui@huawei.com, christoffer.dall@arm.com References: <25971fd5-3774-3389-a82a-04707480c1e0@huawei.com> <1553004668-23296-1-git-send-email-suzuki.poulose@arm.com> <86d0mmynaz.wl-marc.zyngier@arm.com> <5e7e40b4-7983-4440-179a-6f107cee5994@arm.com> <20190320101126.11ff63af@why.wild-wind.fr.eu.org> From: Suzuki K Poulose Message-ID: <4daf0783-fc50-3346-0732-1e3f53c8ccbc@arm.com> Date: Wed, 20 Mar 2019 10:23:39 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190320101126.11ff63af@why.wild-wind.fr.eu.org> Content-Type: text/plain; charset=utf-8; format=flowed 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 Marc, On 20/03/2019 10:11, Marc Zyngier wrote: > On Wed, 20 Mar 2019 09:44:38 +0000 > Suzuki K Poulose wrote: > >> Hi Marc, >> >> On 20/03/2019 08:15, Marc Zyngier wrote: >>> Hi Suzuki, >>> >>> On Tue, 19 Mar 2019 14:11:08 +0000, >>> Suzuki K Poulose wrote: >>>> >>>> We rely on the mmu_notifier call backs to handle the split/merge >>>> of huge pages and thus we are guaranteed that, while creating a >>>> block mapping, either the entire block is unmapped at stage2 or it >>>> is missing permission. >>>> >>>> However, we miss a case where the block mapping is split for dirty >>>> logging case and then could later be made block mapping, if we cancel the >>>> dirty logging. This not only creates inconsistent TLB entries for >>>> the pages in the the block, but also leakes the table pages for >>>> PMD level. >>>> >>>> Handle this corner case for the huge mappings at stage2 by >>>> unmapping the non-huge mapping for the block. This could potentially >>>> release the upper level table. So we need to restart the table walk >>>> once we unmap the range. >>>> >>>> Fixes : ad361f093c1e31d ("KVM: ARM: Support hugetlbfs backed huge pages") >>>> Reported-by: Zheng Xiang >>>> Cc: Zheng Xiang >>>> Cc: Zhengui Yu >>>> Cc: Marc Zyngier >>>> Cc: Christoffer Dall >>>> Signed-off-by: Suzuki K Poulose ... >>>> + if (!pmd_thp_or_huge(old_pmd)) { >>>> + unmap_stage2_range(kvm, addr & S2_PMD_MASK, S2_PMD_SIZE); >>>> + goto retry; >>> >>>> + if (!stage2_pud_huge(kvm, old_pud)) { >>>> + unmap_stage2_range(kvm, addr & S2_PUD_MASK, S2_PUD_SIZE); >>> >> We should really get rid of the S2_P{U/M}D_* definitions, as they are >> always the same as the host. The only thing that changes is the PGD size >> which varies according to the IPA and the concatenation. >> Also what do you think about using P{M,U}D_* instead of S2_P{M,U}D_* above ? I could make that change with the respin. > > Sure, feel free to send a fixed version. I'll drop the currently queued > patch. > Thanks. Sorry for the trouble. Cheers Suzuki 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=-4.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 C4685C43381 for ; Wed, 20 Mar 2019 10:23:54 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7DEB72146E for ; Wed, 20 Mar 2019 10:23:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="j7KmpyZ9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7DEB72146E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uMFBjby9xeOOzgTtDtKKluFkLSohBHBGV49J3AyYwHk=; b=j7KmpyZ92I0GMSizdZyBjRrfw QOW29yXWqnLpChYCSKOztlNknSG7vutatFYdonrQC2yo5g4/tJU71TNgJThNnmPDrwxcYWhL/npzW SKpXnVR/8pZ+XaSIPQChsd8pNVoBW4o3aaP4noyg7iiGVJU1dqR6dHzgQFtVsv05EJmju+P0H8wHz EvwSw9mY2pM8bu25VBULuaK/pG876BcEVkxkbBhK+SuZ2iihpuu3FvACVh08iaJQbBLHYbK2Hvm7R Xo6gyu7UDgIRxdBqwJ3fm9zS8mEF9sZBsWzEktbvVIt8B/B8SyVy5qqotoUIXcXJ+wgF3ynmXmNvf efmTQYndQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h6YNx-0001Uu-Vb; Wed, 20 Mar 2019 10:23:49 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h6YNv-0001UX-04 for linux-arm-kernel@lists.infradead.org; Wed, 20 Mar 2019 10:23:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 38DF680D; Wed, 20 Mar 2019 03:23:46 -0700 (PDT) Received: from [10.1.196.93] (en101.cambridge.arm.com [10.1.196.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 621FE3F71A; Wed, 20 Mar 2019 03:23:43 -0700 (PDT) Subject: Re: [PATCH] kvm: arm: Fix handling of stage2 huge mappings To: marc.zyngier@arm.com References: <25971fd5-3774-3389-a82a-04707480c1e0@huawei.com> <1553004668-23296-1-git-send-email-suzuki.poulose@arm.com> <86d0mmynaz.wl-marc.zyngier@arm.com> <5e7e40b4-7983-4440-179a-6f107cee5994@arm.com> <20190320101126.11ff63af@why.wild-wind.fr.eu.org> From: Suzuki K Poulose Message-ID: <4daf0783-fc50-3346-0732-1e3f53c8ccbc@arm.com> Date: Wed, 20 Mar 2019 10:23:39 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190320101126.11ff63af@why.wild-wind.fr.eu.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190320_032347_095823_78404D2E X-CRM114-Status: GOOD ( 17.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, julien.thierry@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, christoffer.dall@arm.com, zhengxiang9@huawei.com, james.morse@arm.com, lishuo1@hisilicon.com, yuzenghui@huawei.com, wanghaibin.wang@huawei.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, lious.lilei@hisilicon.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Marc, On 20/03/2019 10:11, Marc Zyngier wrote: > On Wed, 20 Mar 2019 09:44:38 +0000 > Suzuki K Poulose wrote: > >> Hi Marc, >> >> On 20/03/2019 08:15, Marc Zyngier wrote: >>> Hi Suzuki, >>> >>> On Tue, 19 Mar 2019 14:11:08 +0000, >>> Suzuki K Poulose wrote: >>>> >>>> We rely on the mmu_notifier call backs to handle the split/merge >>>> of huge pages and thus we are guaranteed that, while creating a >>>> block mapping, either the entire block is unmapped at stage2 or it >>>> is missing permission. >>>> >>>> However, we miss a case where the block mapping is split for dirty >>>> logging case and then could later be made block mapping, if we cancel the >>>> dirty logging. This not only creates inconsistent TLB entries for >>>> the pages in the the block, but also leakes the table pages for >>>> PMD level. >>>> >>>> Handle this corner case for the huge mappings at stage2 by >>>> unmapping the non-huge mapping for the block. This could potentially >>>> release the upper level table. So we need to restart the table walk >>>> once we unmap the range. >>>> >>>> Fixes : ad361f093c1e31d ("KVM: ARM: Support hugetlbfs backed huge pages") >>>> Reported-by: Zheng Xiang >>>> Cc: Zheng Xiang >>>> Cc: Zhengui Yu >>>> Cc: Marc Zyngier >>>> Cc: Christoffer Dall >>>> Signed-off-by: Suzuki K Poulose ... >>>> + if (!pmd_thp_or_huge(old_pmd)) { >>>> + unmap_stage2_range(kvm, addr & S2_PMD_MASK, S2_PMD_SIZE); >>>> + goto retry; >>> >>>> + if (!stage2_pud_huge(kvm, old_pud)) { >>>> + unmap_stage2_range(kvm, addr & S2_PUD_MASK, S2_PUD_SIZE); >>> >> We should really get rid of the S2_P{U/M}D_* definitions, as they are >> always the same as the host. The only thing that changes is the PGD size >> which varies according to the IPA and the concatenation. >> Also what do you think about using P{M,U}D_* instead of S2_P{M,U}D_* above ? I could make that change with the respin. > > Sure, feel free to send a fixed version. I'll drop the currently queued > patch. > Thanks. Sorry for the trouble. Cheers Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel