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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 2707DC43331 for ; Tue, 9 Mar 2021 22:43:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F22726512C for ; Tue, 9 Mar 2021 22:43:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232160AbhCIWmg (ORCPT ); Tue, 9 Mar 2021 17:42:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232108AbhCIWmV (ORCPT ); Tue, 9 Mar 2021 17:42:21 -0500 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADC7FC06175F for ; Tue, 9 Mar 2021 14:42:21 -0800 (PST) Received: by mail-qv1-xf4a.google.com with SMTP id t18so11301361qva.6 for ; Tue, 09 Mar 2021 14:42:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=3FDwgTSdlybb0+QpsP8TGr882VxHot0P+ICZIwf0/7Y=; b=oW2lr/XjXHg3Nm0VgnuAiEKlaz9HAuC1KRfqgW2Mej9IR1fv7tZd29Q0rJNk8kbwyy SQDLQCLoY2lc72OxFhtWMYZoPJHKBy8vxit8uE1so0nAPVLgsuk3eZdprPjmvKUHOWm3 2mEQViqJRN8DaZk1CqdIsy6b9aHers+u7wJkATiOQshwgQ1RBOnKH2sSWPk0SpXzuGjA YYnHrERktO5leQqBWNZg/BmvAaC5g+Nwa6zwwiuzA5i3Z5Wd2GXV7QvUzei/cdpLU7Qj h6GDPr7CqLoqv8pL/Fb698SVhxdivZgCisyogbkB9qTTS/uvjO2Uo1RsDZXj7RnkzVOy bAjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=3FDwgTSdlybb0+QpsP8TGr882VxHot0P+ICZIwf0/7Y=; b=TxoSE4dfSzNG/wyLnglodfNA4ZS1ody4blPyAESe7O0LEBl8XgQ885KVC0eQ/aG87N Gjxo+AMtQVABNq5lXzEX50JO/Ie8b7k0wXq7lRqPiQNnqM4LTT1TALsXUiZD29CT9aqV QWuX9qGUzj23jCv9KqvzTmL3NSCGSCnsRDgDU3RguBHIO1WnqJLSJGnuYOk7mVd0A2bZ c6U8a6sFkxn14PBBzrPx1mKosAZb/bdmKjplcZtuEuPS3iP/Tq3NgXOYTf1UhqYveSA+ IITIt1tMYNbG0F8NHMGWhXnIL23BngXfEyiGESqbNgipmlv+oYgK8D0cN5C1Dmooncpu Cgng== X-Gm-Message-State: AOAM531X5d5l/NUNVyH5NByeX5cAIbYMBfoU/mX5bfgurjO/ABWX8tiH lKuVOcxJefYSx/qHsuraQHubqNN0OQo= X-Google-Smtp-Source: ABdhPJw5U0P6iQMF5biraJ2CMhXIV52ZCiW4aOwwilimTx8W3XMvVhsYpE+xa+8pbuPNKS0hkuqZ2hOdbxU= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:e4dd:6c31:9463:f8da]) (user=seanjc job=sendgmr) by 2002:a0c:b9a5:: with SMTP id v37mr172321qvf.46.1615329740864; Tue, 09 Mar 2021 14:42:20 -0800 (PST) Reply-To: Sean Christopherson Date: Tue, 9 Mar 2021 14:42:06 -0800 In-Reply-To: <20210309224207.1218275-1-seanjc@google.com> Message-Id: <20210309224207.1218275-4-seanjc@google.com> Mime-Version: 1.0 References: <20210309224207.1218275-1-seanjc@google.com> X-Mailer: git-send-email 2.30.1.766.gb4fecdf3b7-goog Subject: [PATCH v2 3/4] KVM: x86/mmu: Use '0' as the one and only value for an invalid PAE root From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Tom Lendacky , Maxim Levitsky , Brijesh Singh Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use '0' to denote an invalid pae_root instead of '0' or INVALID_PAGE. Unlike root_hpa, the pae_roots hold permission bits and thus are guaranteed to be non-zero. Having to deal with both values leads to bugs, e.g. failing to set back to INVALID_PAGE, warning on the wrong value, etc... Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 24 +++++++++++++----------- arch/x86/kvm/mmu/mmu_audit.c | 2 +- arch/x86/kvm/mmu/mmu_internal.h | 10 ++++++++++ 3 files changed, 24 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index febe71935bb5..6b0576ff2846 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3197,11 +3197,14 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) { mmu_free_root_page(kvm, &mmu->root_hpa, &invalid_list); } else if (mmu->pae_root) { - for (i = 0; i < 4; ++i) - if (mmu->pae_root[i] != 0) - mmu_free_root_page(kvm, - &mmu->pae_root[i], - &invalid_list); + for (i = 0; i < 4; ++i) { + if (!IS_VALID_PAE_ROOT(mmu->pae_root[i])) + continue; + + mmu_free_root_page(kvm, &mmu->pae_root[i], + &invalid_list); + mmu->pae_root[i] = INVALID_PAE_ROOT; + } } mmu->root_hpa = INVALID_PAGE; mmu->root_pgd = 0; @@ -3253,8 +3256,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) return -EIO; for (i = 0; i < 4; ++i) { - WARN_ON_ONCE(mmu->pae_root[i] && - VALID_PAGE(mmu->pae_root[i])); + WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i])); root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), i << 30, PT32_ROOT_LEVEL, true); @@ -3328,11 +3330,11 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) } for (i = 0; i < 4; ++i) { - WARN_ON_ONCE(mmu->pae_root[i] && VALID_PAGE(mmu->pae_root[i])); + WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i])); if (mmu->root_level == PT32E_ROOT_LEVEL) { if (!(pdptrs[i] & PT_PRESENT_MASK)) { - mmu->pae_root[i] = 0; + mmu->pae_root[i] = INVALID_PAE_ROOT; continue; } root_gfn = pdptrs[i] >> PAGE_SHIFT; @@ -3450,7 +3452,7 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu) for (i = 0; i < 4; ++i) { hpa_t root = vcpu->arch.mmu->pae_root[i]; - if (root && VALID_PAGE(root)) { + if (IS_VALID_PAE_ROOT(root)) { root &= PT64_BASE_ADDR_MASK; sp = to_shadow_page(root); mmu_sync_children(vcpu, sp); @@ -5307,7 +5309,7 @@ static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) mmu->pae_root = page_address(page); for (i = 0; i < 4; ++i) - mmu->pae_root[i] = INVALID_PAGE; + mmu->pae_root[i] = INVALID_PAE_ROOT; return 0; } diff --git a/arch/x86/kvm/mmu/mmu_audit.c b/arch/x86/kvm/mmu/mmu_audit.c index ced15fd58fde..cedc17b2f60e 100644 --- a/arch/x86/kvm/mmu/mmu_audit.c +++ b/arch/x86/kvm/mmu/mmu_audit.c @@ -70,7 +70,7 @@ static void mmu_spte_walk(struct kvm_vcpu *vcpu, inspect_spte_fn fn) for (i = 0; i < 4; ++i) { hpa_t root = vcpu->arch.mmu->pae_root[i]; - if (root && VALID_PAGE(root)) { + if (IS_VALID_PAE_ROOT(root)) { root &= PT64_BASE_ADDR_MASK; sp = to_shadow_page(root); __mmu_spte_walk(vcpu, sp, fn, 2); diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index ec4fc28b325a..5fe9123fc932 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -20,6 +20,16 @@ extern bool dbg; #define MMU_WARN_ON(x) do { } while (0) #endif +/* + * Unlike regular MMU roots, PAE "roots", a.k.a. PDPTEs/PDPTRs, have a PRESENT + * bit, and thus are guaranteed to be non-zero when valid. And, when a guest + * PDPTR is !PRESENT, its corresponding PAE root cannot be set to INVALID_PAGE, + * as the CPU would treat that as PRESENT PDPTR with reserved bits set. Use + * '0' instead of INVALID_PAGE to indicate an invalid PAE root. + */ +#define INVALID_PAE_ROOT 0 +#define IS_VALID_PAE_ROOT(x) (!!(x)) + struct kvm_mmu_page { struct list_head link; struct hlist_node hash_link; -- 2.30.1.766.gb4fecdf3b7-goog