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=-5.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED,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 7C118C43613 for ; Fri, 21 Jun 2019 09:40:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57F8821530 for ; Fri, 21 Jun 2019 09:40:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727108AbfFUJkp (ORCPT ); Fri, 21 Jun 2019 05:40:45 -0400 Received: from foss.arm.com ([217.140.110.172]:54428 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727105AbfFUJko (ORCPT ); Fri, 21 Jun 2019 05:40:44 -0400 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 6FAED1478; Fri, 21 Jun 2019 02:40:43 -0700 (PDT) Received: from filthy-habits.cambridge.arm.com (filthy-habits.cambridge.arm.com [10.1.197.61]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1B3263F246; Fri, 21 Jun 2019 02:40:42 -0700 (PDT) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Cc: Andre Przywara , Christoffer Dall , Dave Martin , Jintack Lim , Julien Thierry , James Morse , Suzuki K Poulose Subject: [PATCH 58/59] arm64: KVM: nv: Restrict S2 RD/WR permissions to match the guest's Date: Fri, 21 Jun 2019 10:38:42 +0100 Message-Id: <20190621093843.220980-59-marc.zyngier@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190621093843.220980-1-marc.zyngier@arm.com> References: <20190621093843.220980-1-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org When mapping a page in a shadow stage-2, special care must be taken not to be more permissive than the guest is (writable or readable page when the guest hasn't set that permission). Signed-off-by: Marc Zyngier --- arch/arm/include/asm/kvm_mmu.h | 18 ++++++++++++++++++ arch/arm64/include/asm/kvm_mmu.h | 18 ++++++++++++++++++ arch/arm64/include/asm/kvm_nested.h | 10 ++++++++++ virt/kvm/arm/mmu.c | 21 ++++++++++++++++++++- 4 files changed, 66 insertions(+), 1 deletion(-) diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 7a6e9008ed45..7aa7182ca744 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -113,6 +113,12 @@ static inline pud_t kvm_s2pud_mkexec(pud_t pud) return pud; } +static inline pud_t kvm_s2pud_revoke_read(pud_t pud) +{ + WARN_ON(1); + return pud; +} + static inline bool kvm_s2pud_exec(pud_t *pud) { WARN_ON(1); @@ -155,6 +161,18 @@ static inline pmd_t kvm_s2pmd_mkexec(pmd_t pmd) return pmd; } +static inline pte_t kvm_s2pte_revoke_read(pte_t pte) +{ + pte_val(pte) &= ~L_PTE_S2_RDONLY; + return pte; +} + +static inline pmd_t kvm_s2pmd_revoke_read(pmd_t pmd) +{ + pmd_val(pmd) &= ~L_PMD_S2_RDONLY; + return pmd; +} + static inline void kvm_set_s2pte_readonly(pte_t *pte) { pte_val(*pte) = (pte_val(*pte) & ~L_PTE_S2_RDWR) | L_PTE_S2_RDONLY; diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 53103607065a..f46ea12e55c2 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -238,6 +238,24 @@ static inline pud_t kvm_s2pud_mkexec(pud_t pud) return pud; } +static inline pte_t kvm_s2pte_revoke_read(pte_t pte) +{ + pte_val(pte) &= ~PTE_S2_RDONLY; + return pte; +} + +static inline pmd_t kvm_s2pmd_revoke_read(pmd_t pmd) +{ + pmd_val(pmd) &= ~PMD_S2_RDONLY; + return pmd; +} + +static inline pud_t kvm_s2pud_revoke_read(pud_t pud) +{ + pud_val(pud) &= ~PUD_S2_RDONLY; + return pud; +} + static inline void kvm_set_s2pte_readonly(pte_t *ptep) { pteval_t old_pteval, pteval; diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index 3b415bc76ced..76777b1b9419 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -42,6 +42,16 @@ static inline u32 kvm_s2_trans_esr(struct kvm_s2_trans *trans) return trans->esr; } +static inline bool kvm_s2_trans_readable(struct kvm_s2_trans *trans) +{ + return trans->readable; +} + +static inline bool kvm_s2_trans_writable(struct kvm_s2_trans *trans) +{ + return trans->writable; +} + extern int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, struct kvm_s2_trans *result); diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 0ea79e543b29..bc8cb529647b 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1729,7 +1729,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, unsigned long hva, unsigned long fault_status) { int ret; - bool write_fault, writable; + bool write_fault, writable, readable = true; bool exec_fault, needs_exec; unsigned long mmu_seq; phys_addr_t ipa = fault_ipa; @@ -1842,6 +1842,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, writable = false; } + /* + * Potentially reduce shadow S2 permissions to match the guest's own + * S2. For exec faults, we'd only reach this point if the guest + * actually allowed it (see kvm_s2_handle_perm_fault). + */ + if (kvm_is_shadow_s2_fault(vcpu)) { + writable &= kvm_s2_trans_writable(nested); + readable &= kvm_s2_trans_readable(nested); + } + spin_lock(&kvm->mmu_lock); if (mmu_notifier_retry(kvm, mmu_seq)) goto out_unlock; @@ -1887,6 +1897,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (writable) new_pud = kvm_s2pud_mkwrite(new_pud); + if (!readable) + new_pud = kvm_s2pud_revoke_read(new_pud); + if (needs_exec) new_pud = kvm_s2pud_mkexec(new_pud); @@ -1899,6 +1912,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (writable) new_pmd = kvm_s2pmd_mkwrite(new_pmd); + if (!readable) + new_pmd = kvm_s2pmd_revoke_read(new_pmd); + if (needs_exec) new_pmd = kvm_s2pmd_mkexec(new_pmd); @@ -1911,6 +1927,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, mark_page_dirty(kvm, gfn); } + if (!readable) + new_pte = kvm_s2pte_revoke_read(new_pte); + if (needs_exec) new_pte = kvm_s2pte_mkexec(new_pte); -- 2.20.1