From patchwork Wed May 12 14:42:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 438383 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 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 213F1C2B9F2 for ; Wed, 12 May 2021 15:59:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA1C561CC2 for ; Wed, 12 May 2021 15:59:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231649AbhELQAi (ORCPT ); Wed, 12 May 2021 12:00:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:37094 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237763AbhELP4U (ORCPT ); Wed, 12 May 2021 11:56:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 11D0161961; Wed, 12 May 2021 15:28:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620833306; bh=GRSUwTnrJZOF74bKXwdbEIue1P8EKYFPuHzPKGkJUeg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Uvo02Q76kzP593neox0RY++uBhB1fY+DuimerCZbwJqyjRHM8llJw5CIBybqWbjDk 9vVfX6HNwFYhohbtNhGRrBkYwc7Hu00WS0FOjm+LXQ0eKTsZqfTk1GLwabBGYTcaHD l9ape0Y8Qqdq8M3PajUOOGyUcPXIY9g8Sd0NGAyo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Gardon , Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.11 096/601] KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT with 64-bit Date: Wed, 12 May 2021 16:42:53 +0200 Message-Id: <20210512144830.990795373@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210512144827.811958675@linuxfoundation.org> References: <20210512144827.811958675@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Christopherson commit 04d45551a1eefbea42655da52f56e846c0af721a upstream. Allocate the so called pae_root page on-demand, along with the lm_root page, when shadowing 32-bit NPT with 64-bit NPT, i.e. when running a 32-bit L1. KVM currently only allocates the page when NPT is disabled, or when L0 is 32-bit (using PAE paging). Note, there is an existing memory leak involving the MMU roots, as KVM fails to free the PAE roots on failure. This will be addressed in a future commit. Fixes: ee6268ba3a68 ("KVM: x86: Skip pae_root shadow allocation if tdp enabled") Fixes: b6b80c78af83 ("KVM: x86/mmu: Allocate PAE root array when using SVM's 32-bit NPT") Cc: stable@vger.kernel.org Reviewed-by: Ben Gardon Signed-off-by: Sean Christopherson Message-Id: <20210305011101.3597423-3-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/mmu/mmu.c | 44 +++++++++++++++++++++++++++++--------------- 1 file changed, 29 insertions(+), 15 deletions(-) --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3203,14 +3203,14 @@ void kvm_mmu_free_roots(struct kvm_vcpu if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL && (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) { mmu_free_root_page(kvm, &mmu->root_hpa, &invalid_list); - } else { + } 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); - mmu->root_hpa = INVALID_PAGE; } + mmu->root_hpa = INVALID_PAGE; mmu->root_pgd = 0; } @@ -3322,9 +3322,23 @@ static int mmu_alloc_shadow_roots(struct * the shadow page table may be a PAE or a long mode page table. */ pm_mask = PT_PRESENT_MASK; - if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) + if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) { pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK; + /* + * Allocate the page for the PDPTEs when shadowing 32-bit NPT + * with 64-bit only when needed. Unlike 32-bit NPT, it doesn't + * need to be in low mem. See also lm_root below. + */ + if (!vcpu->arch.mmu->pae_root) { + WARN_ON_ONCE(!tdp_enabled); + + vcpu->arch.mmu->pae_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + if (!vcpu->arch.mmu->pae_root) + return -ENOMEM; + } + } + for (i = 0; i < 4; ++i) { MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i])); if (vcpu->arch.mmu->root_level == PT32E_ROOT_LEVEL) { @@ -3347,21 +3361,19 @@ static int mmu_alloc_shadow_roots(struct vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root); /* - * If we shadow a 32 bit page table with a long mode page - * table we enter this path. + * When shadowing 32-bit or PAE NPT with 64-bit NPT, the PML4 and PDP + * tables are allocated and initialized at MMU creation as there is no + * equivalent level in the guest's NPT to shadow. Allocate the tables + * on demand, as running a 32-bit L1 VMM is very rare. The PDP is + * handled above (to share logic with PAE), deal with the PML4 here. */ if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) { if (vcpu->arch.mmu->lm_root == NULL) { - /* - * The additional page necessary for this is only - * allocated on demand. - */ - u64 *lm_root; lm_root = (void*)get_zeroed_page(GFP_KERNEL_ACCOUNT); - if (lm_root == NULL) - return 1; + if (!lm_root) + return -ENOMEM; lm_root[0] = __pa(vcpu->arch.mmu->pae_root) | pm_mask; @@ -5310,9 +5322,11 @@ static int __kvm_mmu_create(struct kvm_v * while the PDP table is a per-vCPU construct that's allocated at MMU * creation. When emulating 32-bit mode, cr3 is only 32 bits even on * x86_64. Therefore we need to allocate the PDP table in the first - * 4GB of memory, which happens to fit the DMA32 zone. Except for - * SVM's 32-bit NPT support, TDP paging doesn't use PAE paging and can - * skip allocating the PDP table. + * 4GB of memory, which happens to fit the DMA32 zone. TDP paging + * generally doesn't use PAE paging and can skip allocating the PDP + * table. The main exception, handled here, is SVM's 32-bit NPT. The + * other exception is for shadowing L1's 32-bit or PAE NPT on 64-bit + * KVM; that horror is handled on-demand by mmu_alloc_shadow_roots(). */ if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL) return 0;