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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 06524C433DB for ; Fri, 5 Mar 2021 19:14:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6BB364F69 for ; Fri, 5 Mar 2021 19:14:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229957AbhCETN6 (ORCPT ); Fri, 5 Mar 2021 14:13:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:34488 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229783AbhCETNd (ORCPT ); Fri, 5 Mar 2021 14:13:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id EE2F4650A0; Fri, 5 Mar 2021 19:13:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614971613; bh=cmU1v4HxoU7I1TscIKOCjbmB6ohA+V07l9MWa8IiQYw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hQ7xvZ8m48Y3m8nLo8R4/145zV++RcmVEQTpO5sNUIxRg2MwSaq0Jr0khLnSMW9nv U2nVsTOqrA+myTkN4udZxTTKPQCgSil1cwOEPGK1Lm92QJMSvZP2Tm5fqS/ixLKMM6 cLBn1Xw4NTDlc+iJYfsOY4qP+ZPd3Niu4vDddQdL0j3qA5hTeOUpkq2XNGf1KewlXv InlVKSEKrUFn6KBdQq3JRjRaOzty7YM8GHux/ewmDd8Q55kQIyGUMPlX50L6DVW2FW f5FI8ZAnA1jBr/sNKI2Njp+pJtx4nApDezuqwMQhkO6jdStUWZfoOvWr+ACcRF1J7G kM56jq46kIHRQ== Date: Fri, 5 Mar 2021 19:13:27 +0000 From: Will Deacon To: Quentin Perret Cc: catalin.marinas@arm.com, maz@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, android-kvm@google.com, linux-kernel@vger.kernel.org, kernel-team@android.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, tabba@google.com, mark.rutland@arm.com, dbrazdil@google.com, mate.toth-pal@arm.com, seanjc@google.com, robh+dt@kernel.org Subject: Re: [PATCH v3 32/32] KVM: arm64: Protect the .hyp sections from the host Message-ID: <20210305191327.GD23633@willie-the-truck> References: <20210302150002.3685113-1-qperret@google.com> <20210302150002.3685113-33-qperret@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210302150002.3685113-33-qperret@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 02, 2021 at 03:00:02PM +0000, Quentin Perret wrote: > When KVM runs in nVHE protected mode, use the host stage 2 to unmap the > hypervisor sections. The long-term goal is to ensure the EL2 code can > remain robust regardless of the host's state, so this starts by making > sure the host cannot e.g. write to the .hyp sections directly. > > Signed-off-by: Quentin Perret > --- > arch/arm64/include/asm/kvm_asm.h | 1 + > arch/arm64/kvm/arm.c | 46 +++++++++++++++++++ > arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 + > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 9 ++++ > arch/arm64/kvm/hyp/nvhe/mem_protect.c | 22 +++++++++ > 5 files changed, 80 insertions(+) [...] > static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) > diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > index 2252ad1a8945..ed480facdc88 100644 > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > @@ -196,6 +196,28 @@ static int host_stage2_idmap(u64 addr) > return ret; > } > > +int __pkvm_host_unmap(phys_addr_t start, phys_addr_t end) > +{ > + struct kvm_mem_range r1, r2; > + int ret; > + > + /* > + * host_stage2_unmap_dev_all() currently relies on MMIO mappings being > + * non-persistent, so don't allow PROT_NONE in MMIO range. > + */ > + if (!find_mem_range(start, &r1) || !find_mem_range(end, &r2)) > + return -EINVAL; > + if (r1.start != r2.start) > + return -EINVAL; Feels like this should be in a helper to determine whether or not a range is solely covered by memory. Either way: Acked-by: Will Deacon Will