From patchwork Mon May 15 17:30:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13241988 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 0C8A3C77B75 for ; Mon, 15 May 2023 17:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244917AbjEORvO (ORCPT ); Mon, 15 May 2023 13:51:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244708AbjEORuo (ORCPT ); Mon, 15 May 2023 13:50:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6CBB1B76D for ; Mon, 15 May 2023 10:48:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id AF34D6233D for ; Mon, 15 May 2023 17:48:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E472C433A0; Mon, 15 May 2023 17:48:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684172933; bh=L+tMg6YTx03e/q895UbxlnBfVB1S45WLXO3Fsf4tpR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CPO+YTKcEDkztknpPzrcQiS9jbXEoiUwM9+/7B0Y9mwP5+D9hzBVltl3ud/J67Ud+ f1zsQBMWLDLu9OxxsXVxOtHy7aEVt4ge9svGHyKnRHySPHhCNiD11AnPYrLPR2HRCB ZMCPw8BuEQ0pYx3SaDvHFQY6uDalY/Nz5WbRJYA0iV8Qinm3BMQYxD9t8ldzX8NQkD Wz41Bvb8I4fM8Rkx+G/d6yT+LqIDvlndl2TAYfBE3jo7R2RnAiV1K/YB/NowDl7GdG rOQiBuxTYjC2WmPuvHPOaee2bGpDqeGby2OyHw1SvfZQyIaOt9fcxUco1gQdavawRi jW6dM8j2xyeYw== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pyc2k-00FJAF-Qh; Mon, 15 May 2023 18:31:30 +0100 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandru Elisei , Andre Przywara , Chase Conklin , Christoffer Dall , Ganapatrao Kulkarni , Darren Hart , Jintack Lim , Russell King , Miguel Luis , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH v10 28/59] KVM: arm64: nv: Restrict S2 RD/WR permissions to match the guest's Date: Mon, 15 May 2023 18:30:32 +0100 Message-Id: <20230515173103.1017669-29-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230515173103.1017669-1-maz@kernel.org> References: <20230515173103.1017669-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, alexandru.elisei@arm.com, andre.przywara@arm.com, chase.conklin@arm.com, christoffer.dall@arm.com, gankulkarni@os.amperecomputing.com, darren@os.amperecomputing.com, jintack@cs.columbia.edu, rmk+kernel@armlinux.org.uk, miguel.luis@oracle.com, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false 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). Reviewed-by: Alexandru Elisei Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_nested.h | 15 +++++++++++++++ arch/arm64/kvm/mmu.c | 14 +++++++++++++- arch/arm64/kvm/nested.c | 2 +- 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h index d2cee4faa387..f20d272fcd6d 100644 --- a/arch/arm64/include/asm/kvm_nested.h +++ b/arch/arm64/include/asm/kvm_nested.h @@ -91,6 +91,21 @@ 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; +} + +static inline bool kvm_s2_trans_executable(struct kvm_s2_trans *trans) +{ + return !(trans->upper_attr & BIT(54)); +} + extern int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, struct kvm_s2_trans *result); extern int kvm_s2_handle_perm_fault(struct kvm_vcpu *vcpu, diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index bc6f004d4ffb..1e19c59b8235 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1427,6 +1427,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (exec_fault && device) return -ENOEXEC; + /* + * 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 (nested) { + writable &= kvm_s2_trans_writable(nested); + if (!kvm_s2_trans_readable(nested)) + prot &= ~KVM_PGTABLE_PROT_R; + } + read_lock(&kvm->mmu_lock); pgt = vcpu->arch.hw_mmu->pgt; if (mmu_invalidate_retry(kvm, mmu_seq)) @@ -1469,7 +1480,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (device) prot |= KVM_PGTABLE_PROT_DEVICE; - else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) + else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC) && + (!nested || kvm_s2_trans_executable(nested))) prot |= KVM_PGTABLE_PROT_X; /* diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index 2538e0c632f2..73c0be25345a 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -499,7 +499,7 @@ int kvm_s2_handle_perm_fault(struct kvm_vcpu *vcpu, struct kvm_s2_trans *trans) return 0; if (kvm_vcpu_trap_is_iabt(vcpu)) { - forward_fault = (trans->upper_attr & BIT(54)); + forward_fault = !kvm_s2_trans_executable(trans); } else { bool write_fault = kvm_is_write_fault(vcpu);