From patchwork Thu Oct 20 13:38:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 13013487 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 6D179C433FE for ; Thu, 20 Oct 2022 13:39:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230347AbiJTNjN (ORCPT ); Thu, 20 Oct 2022 09:39:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230287AbiJTNjJ (ORCPT ); Thu, 20 Oct 2022 09:39:09 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4FF51A2E34 for ; Thu, 20 Oct 2022 06:39:04 -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 1A9E961B7F for ; Thu, 20 Oct 2022 13:39:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51DAFC433D7; Thu, 20 Oct 2022 13:39:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666273143; bh=yQYxpwGVyoU+XJXTPxigRCKt0VDReCR4zBLvixYhuxo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L+YsItLpaffwOQvbgkn1m89kTo7cQgGb0/BvjIKzZZCfnQKL8Au6FfZesFx6xbdr4 KiRFhC4v1MqLFE1ZV1poqz8mMwieVH51wdr+MyFMx3XbhVkIY2NG6xZee5oEqS5R3W 1ATIJ8t7kWmUkrazCkqCNQMpQaFIY8SzhdAfQzGnSvaivNcMUh9iqfq6Gyf69BvLkJ C5tud5JbwXFcWtPJAz0Ck7a3sA1XX9nBGIO0c/8JwURmelZR7/oaFeIi4Btse/vDdv feeZQBh7Fp9whYsZENTLPDCCNTmlAOjeS2hldUItFoHdMvO9qujk4mDQ6mCUHRyQPx AOgxJvH7V0UfQ== From: Will Deacon To: kvmarm@lists.linux.dev Cc: Will Deacon , Sean Christopherson , Vincent Donnefort , Alexandru Elisei , Catalin Marinas , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?q?=C3=A9?= , James Morse , Chao Peng , Quentin Perret , Suzuki K Poulose , Mark Rutland , Fuad Tabba , Oliver Upton , Marc Zyngier , kernel-team@android.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 07/25] KVM: arm64: Prevent the donation of no-map pages Date: Thu, 20 Oct 2022 14:38:09 +0100 Message-Id: <20221020133827.5541-8-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20221020133827.5541-1-will@kernel.org> References: <20221020133827.5541-1-will@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Quentin Perret Memory regions marked as "no-map" in the host device-tree routinely include TrustZone carev-outs and DMA pools. Although donating such pages to the hypervisor may not breach confidentiality, it could be used to corrupt its state in uncontrollable ways. To prevent this, let's block host-initiated memory transitions targeting "no-map" pages altogether in nVHE protected mode as there should be no valid reason to do this in current operation. Thankfully, the pKVM EL2 hypervisor has a full copy of the host's list of memblock regions, so we can easily check for the presence of the MEMBLOCK_NOMAP flag on a region containing pages being donated from the host. Reviewed-by: Philippe Mathieu-Daudé Tested-by: Vincent Donnefort Signed-off-by: Quentin Perret Signed-off-by: Will Deacon --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index c30402737548..a7156fd13bc8 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -193,7 +193,7 @@ struct kvm_mem_range { u64 end; }; -static bool find_mem_range(phys_addr_t addr, struct kvm_mem_range *range) +static struct memblock_region *find_mem_range(phys_addr_t addr, struct kvm_mem_range *range) { int cur, left = 0, right = hyp_memblock_nr; struct memblock_region *reg; @@ -216,18 +216,28 @@ static bool find_mem_range(phys_addr_t addr, struct kvm_mem_range *range) } else { range->start = reg->base; range->end = end; - return true; + return reg; } } - return false; + return NULL; } bool addr_is_memory(phys_addr_t phys) { struct kvm_mem_range range; - return find_mem_range(phys, &range); + return !!find_mem_range(phys, &range); +} + +static bool addr_is_allowed_memory(phys_addr_t phys) +{ + struct memblock_region *reg; + struct kvm_mem_range range; + + reg = find_mem_range(phys, &range); + + return reg && !(reg->flags & MEMBLOCK_NOMAP); } static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range) @@ -346,7 +356,7 @@ static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot pr static int host_stage2_idmap(u64 addr) { struct kvm_mem_range range; - bool is_memory = find_mem_range(addr, &range); + bool is_memory = !!find_mem_range(addr, &range); enum kvm_pgtable_prot prot; int ret; @@ -424,7 +434,7 @@ static int __check_page_state_visitor(u64 addr, u64 end, u32 level, struct check_walk_data *d = arg; kvm_pte_t pte = *ptep; - if (kvm_pte_valid(pte) && !addr_is_memory(kvm_pte_to_phys(pte))) + if (kvm_pte_valid(pte) && !addr_is_allowed_memory(kvm_pte_to_phys(pte))) return -EINVAL; return d->get_page_state(pte) == d->desired ? 0 : -EPERM;