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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 677C6C433E6 for ; Fri, 28 Aug 2020 15:51:34 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 17C132075B for ; Fri, 28 Aug 2020 15:51:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="KyoL7yay" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 17C132075B 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+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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type: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=vTwu4dQy23Q0APjwrczBPW4fu9IwSneP/Pr4ECU8LQw=; b=KyoL7yayJAuke2nO9LP4vpDXH tCJRTezzZrvSD/lu0mQ94zNw0t/ASndQPLhfuJeOnopwBt1xVePvTTrp2KRgpFKBL8SIn1muhOOvI uicxAVXlmCyDmCiQP7Hg0VAPZy8+auzhf7fRxgBPZjoakEwWz3XVmirdY92sHW1Z1TGH/RsM45Daz ScIQordBUWxoNF9xk8xxTuduQrGd/+askpB3fEmL9UtSPzi5NWIflPPsX8UHA82FSEShQrpxWMEhE RP70xpc5SEM9eFtawv/sWgkbO2ddC3L4z25HoMsO/b+RFjXwhNjjQhQccNg1GGdZbpBSOQYM7v2xK +kcp2DdWg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBgdr-0005tc-Pj; Fri, 28 Aug 2020 15:50:15 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBgdp-0005tD-OS for linux-arm-kernel@lists.infradead.org; Fri, 28 Aug 2020 15:50:14 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1FF9F31B; Fri, 28 Aug 2020 08:50:10 -0700 (PDT) Received: from [192.168.0.110] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 49B9D3F71F; Fri, 28 Aug 2020 08:50:09 -0700 (PDT) Subject: Re: [PATCH v3 02/21] KVM: arm64: Add stand-alone page-table walker infrastructure To: Will Deacon , kvmarm@lists.cs.columbia.edu References: <20200825093953.26493-1-will@kernel.org> <20200825093953.26493-3-will@kernel.org> From: Alexandru Elisei Message-ID: <8afa26de-1839-7e5e-a324-351b241e0976@arm.com> Date: Fri, 28 Aug 2020 16:51:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200825093953.26493-3-will@kernel.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200828_115013_864736_C5EB7EF1 X-CRM114-Status: GOOD ( 12.98 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marc Zyngier , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, Catalin Marinas Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Will, On 8/25/20 10:39 AM, Will Deacon wrote: > [..] > +static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp) > +{ > + kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(__pa(childp)); > + > + pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE); > + pte |= KVM_PTE_VALID; > + > + WARN_ON(kvm_pte_valid(old)); > + smp_store_release(ptep, pte); > +} > + > +static bool kvm_set_valid_leaf_pte(kvm_pte_t *ptep, u64 pa, kvm_pte_t attr, > + u32 level) > +{ > + kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(pa); > + u64 type = (level == KVM_PGTABLE_MAX_LEVELS - 1) ? KVM_PTE_TYPE_PAGE : > + KVM_PTE_TYPE_BLOCK; > + > + pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI); > + pte |= FIELD_PREP(KVM_PTE_TYPE, type); > + pte |= KVM_PTE_VALID; > + > + /* Tolerate KVM recreating the exact same mapping. */ > + if (kvm_pte_valid(old)) > + return old == pte; > + > + smp_store_release(ptep, pte); > + return true; > +} These two functions look inconsistent to me - we refuse to update a valid leaf entry with a new value, but we allow updating a valid table. Is there something that I'm not taking into account? Thanks, Alex _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel