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 ADB48C43381 for ; Wed, 20 Mar 2019 10:35:25 +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 62A582075C for ; Wed, 20 Mar 2019 10:35:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OJEpDKkT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62A582075C 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-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=UaKtCCj2TAuZJO1APluxzATlrVHdtsGhtqwLiVoo12Q=; b=OJEpDKkTF/OtIQ aE1uV0Y+nR4cDjV5xOOmT4qhx7qMjAa6JMxctwsZN9fcJIXTutaR4kmMY//CBomNiZqEMZkK4ZgK1 XpTn5GYf+U9ZRrOwUCeZwmoOAtO/MFllQc9Bf3EDpo057OGesRhEIEWjBSIFxEeN0irrIJxGt/Pde N9x9zXb+nn9CqxoPF6pVlwltz03OjMLT2VVFT7IrcrNHGPwa5/7EF/eMx9o1fp02dgz9pQ47D+ftK MVpuNTuQdtcqvgvGJffiaW9gYwLh0mi5OBcbKPZZqc626sl7Xit2BAzQ/WO2G+OEJXRCMaMkrezA8 9iFw0OGSehN1OgtZu8yA==; 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 1h6YZ7-0006Rg-CX; Wed, 20 Mar 2019 10:35:21 +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 1h6YZ4-0006Qz-MT for linux-arm-kernel@lists.infradead.org; Wed, 20 Mar 2019 10:35:19 +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 66DEF80D; Wed, 20 Mar 2019 03:35:18 -0700 (PDT) Received: from why.wild-wind.fr.eu.org (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7F8953F71A; Wed, 20 Mar 2019 03:35:15 -0700 (PDT) Date: Wed, 20 Mar 2019 10:35:11 +0000 From: Marc Zyngier To: Suzuki K Poulose Subject: Re: [PATCH] kvm: arm: Fix handling of stage2 huge mappings Message-ID: <20190320103511.11d777b9@why.wild-wind.fr.eu.org> In-Reply-To: <4daf0783-fc50-3346-0732-1e3f53c8ccbc@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> <4daf0783-fc50-3346-0732-1e3f53c8ccbc@arm.com> Organization: ARM Ltd X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190320_033518_750101_B0E696AA X-CRM114-Status: GOOD ( 20.77 ) 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 20 Mar 2019 10:23:39 +0000 Suzuki K Poulose wrote: Hi Suzuki, > 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. Given that this is a fix, I'd like it to be as small as obvious as possible, making it easier to backport. I'm happy to take another patch for 5.2 that will drop the whole S2_P* if we still think that this should be the case (though what I'd really like is to have architectural levels instead of these arbitrary definitions). Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel