From patchwork Fri May 13 20:28:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12849458 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 112E6C433EF for ; Fri, 13 May 2022 20:29:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1384308AbiEMU3m (ORCPT ); Fri, 13 May 2022 16:29:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384377AbiEMU3X (ORCPT ); Fri, 13 May 2022 16:29:23 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 433697982E for ; Fri, 13 May 2022 13:29:06 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id y17-20020a637d11000000b003ab06870074so4665751pgc.15 for ; Fri, 13 May 2022 13:29:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=q0LsgOUH6fh/EMGEgMPSdRPwXrsuMMeqwhsgKGGJKHM=; b=FGxarLHA+9K52scni+0BvI2r1sGYFMQ8ypD5JrPvbOSwPU9wL5H5xXpPj6SPlnFQo5 77FMMdUCFXJ172bCdvmizQ5dwzAzNPBL14eyXHYO1loOk6evG/XFwejoYS5BQGBUrXQ2 ChBpPuIe0wTGv9hAp1PMjAQwPoDlrK0JMNhSNCdXYfoPbALy7n8+hVOiG78R4Nlviubw yX1cElPjLpBelQzruz1n/3iMAwQuADdavi0cXcBE70uWVMCLNx4cW26GKCmw0UBQEvTJ n8lv6QNlxzeWu/aQgR23+ZkPFVy+RkmSKiMrvwlINFJQ4kXVRLBLamadFnzmlOneOpU9 EoxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=q0LsgOUH6fh/EMGEgMPSdRPwXrsuMMeqwhsgKGGJKHM=; b=15G96CmJ/J15UbQ3jYkQ6byKZw0uUu/p3BXt+y6j98VDAHaPBbCXdr9sjeqUyGDCgG 11R4+yM6DT0zY7jhvcDzmOadGkgGtlPCj0ooGgc2wWHHN/pepW6DMM24UGWqR0lK1Rgy nrzM0/47APElh7hYJygHv3dxJLr48Az3Vdic5c2XF8M7MyHUHqEhZ/29cNBCZTDVf/3E b02sDxZnLFzleyb0vyy8is6e02T95SY5FTbW5ojYhisGlDJ0ONhxHbtsISLe3gxGSaYv 6yCDByZrmdGbK5fawSVrzy+aNXDLp9SwwdSy1KLfISNW0zghUdIE/2FfAy+/11R0b82C GC6w== X-Gm-Message-State: AOAM531je0UG5q+cQWaEzFpgs0I1drV369FrdERIzarSy9gNn8Cag4nb OYKws3wjm2cc71hhAK5E0rRTZzgeCnZzDg== X-Google-Smtp-Source: ABdhPJyUcDKTztJncnxZ1AkdOXStWsx/xe9HMUQEm28uobbF5HXrHt4Y707ip22/3NSqnqp1w2Vs6/ksvKFagw== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a05:6a00:1805:b0:50d:ee59:b579 with SMTP id y5-20020a056a00180500b0050dee59b579mr6179751pfa.70.1652473740312; Fri, 13 May 2022 13:29:00 -0700 (PDT) Date: Fri, 13 May 2022 20:28:15 +0000 In-Reply-To: <20220513202819.829591-1-dmatlack@google.com> Message-Id: <20220513202819.829591-18-dmatlack@google.com> Mime-Version: 1.0 References: <20220513202819.829591-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.550.gb090851708-goog Subject: [PATCH v5 17/21] KVM: x86/mmu: Extend make_huge_page_split_spte() for the shadow MMU From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , Lai Jiangshan , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently make_huge_page_split_spte() assumes execute permissions can be granted to any 4K SPTE when splitting huge pages. This is true for the TDP MMU but is not necessarily true for the shadow MMU, since KVM may be shadowing a non-executable huge page. To fix this, pass in the role of the child shadow page where the huge page will be split and derive the execution permission from that. This is correct because huge pages are always split with direct shadow page and thus the shadow page role contains the correct access permissions. No functional change intended. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/spte.c | 16 ++++++++-------- arch/x86/kvm/mmu/spte.h | 2 +- arch/x86/kvm/mmu/tdp_mmu.c | 2 +- 3 files changed, 10 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index b5960bbde7f7..237e8dc12993 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -244,10 +244,10 @@ static u64 make_spte_executable(u64 spte) * This is used during huge page splitting to build the SPTEs that make up the * new page table. */ -u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) +u64 make_huge_page_split_spte(u64 huge_spte, union kvm_mmu_page_role role, + int index) { u64 child_spte; - int child_level; if (WARN_ON_ONCE(!is_shadow_present_pte(huge_spte))) return 0; @@ -256,23 +256,23 @@ u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) return 0; child_spte = huge_spte; - child_level = huge_level - 1; /* * The child_spte already has the base address of the huge page being * split. So we just have to OR in the offset to the page at the next * lower level for the given index. */ - child_spte |= (index * KVM_PAGES_PER_HPAGE(child_level)) << PAGE_SHIFT; + child_spte |= (index * KVM_PAGES_PER_HPAGE(role.level)) << PAGE_SHIFT; - if (child_level == PG_LEVEL_4K) { + if (role.level == PG_LEVEL_4K) { child_spte &= ~PT_PAGE_SIZE_MASK; /* - * When splitting to a 4K page, mark the page executable as the - * NX hugepage mitigation no longer applies. + * When splitting to a 4K page where execution is allowed, mark + * the page executable as the NX hugepage mitigation no longer + * applies. */ - if (is_nx_huge_page_enabled()) + if ((role.access & ACC_EXEC_MASK) && is_nx_huge_page_enabled()) child_spte = make_spte_executable(child_spte); } diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 0127bb6e3c7d..3dada44cc066 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -425,7 +425,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch, bool can_unsync, bool host_writable, u64 *new_spte); -u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index); +u64 make_huge_page_split_spte(u64 huge_spte, union kvm_mmu_page_role role, int index); u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); u64 mark_spte_for_access_track(u64 spte); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 841feaa48be5..a5472ee56080 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1488,7 +1488,7 @@ static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter, * not been linked in yet and thus is not reachable from any other CPU. */ for (i = 0; i < PT64_ENT_PER_PAGE; i++) - sp->spt[i] = make_huge_page_split_spte(huge_spte, level, i); + sp->spt[i] = make_huge_page_split_spte(huge_spte, sp->role, i); /* * Replace the huge spte with a pointer to the populated lower level