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=-12.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 82D1CC47E4D for ; Thu, 15 Jul 2021 16:32:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 678EA613D3 for ; Thu, 15 Jul 2021 16:32:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231726AbhGOQfO (ORCPT ); Thu, 15 Jul 2021 12:35:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:42938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229738AbhGOQfK (ORCPT ); Thu, 15 Jul 2021 12:35:10 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7F3D5613F0; Thu, 15 Jul 2021 16:32:16 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1m44HW-00DYjr-Jf; Thu, 15 Jul 2021 17:32:14 +0100 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: will@kernel.org, qperret@google.com, dbrazdil@google.com, Srivatsa Vaddagiri , Shanker R Donthineni , James Morse , Suzuki K Poulose , Alexandru Elisei , kernel-team@android.com Subject: [PATCH 00/16] KVM: arm64: MMIO guard PV services Date: Thu, 15 Jul 2021 17:31:43 +0100 Message-Id: <20210715163159.1480168-1-maz@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, will@kernel.org, qperret@google.com, dbrazdil@google.com, vatsa@codeaurora.org, sdonthineni@nvidia.com, james.morse@arm.com, suzuki.poulose@arm.com, alexandru.elisei@arm.com, kernel-team@android.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: linux-kernel@vger.kernel.org KVM/arm64 currently considers that any memory access outside of a memslot is a MMIO access. This so far has served us very well, but obviously relies on the guest trusting the host, and especially userspace to do the right thing. As we keep on hacking away at pKVM, it becomes obvious that this trust model is not really fit for a confidential computing environment, and that the guest would require some guarantees that emulation only occurs on portions of the address space that have clearly been identified for this purpose. This series aims at providing the two sides of the above coin: - a set of PV services (collectively called 'MMIO guard' -- better name required!) where the guest can flag portion of its address space that it considers as MMIO, with map/unmap semantics. Any attempt to access a MMIO range outside of these regions will result in an external abort being injected. - a set of hooks into the ioremap code allowing a Linux guest to tell KVM about things it want to consider as MMIO. I definitely hate this part of the series, as it feels clumsy and brittle. For now, the enrolment in this scheme is controlled by a guest kernel command-line parameters, but it is expected that KVM will enforce this for protected VMs. Note that this crucially misses a save/restore interface for non protected VMs, and I currently don't have a good solution for that. Ideas welcome. I also plan to use this series as a base for some other purposes, namely to trick the guest in telling us how it maps things like prefetchable BARs (see the discussion at [1]). That part is not implemented yet, but there is already some provision to pass the MAIR index across. Patches on top of 5.14-rc1, branch pushed at the usual location. [1] 20210429162906.32742-1-sdonthineni@nvidia.com Marc Zyngier (16): KVM: arm64: Generalise VM features into a set of flags KVM: arm64: Don't issue CMOs when the physical address is invalid KVM: arm64: Turn kvm_pgtable_stage2_set_owner into kvm_pgtable_stage2_annotate KVM: arm64: Add MMIO checking infrastructure KVM: arm64: Plumb MMIO checking into the fault handling KVM: arm64: Force a full unmap on vpcu reinit KVM: arm64: Wire MMIO guard hypercalls KVM: arm64: Add tracepoint for failed MMIO guard check KVM: arm64: Advertise a capability for MMIO guard KVM: arm64: Add some documentation for the MMIO guard feature firmware/smccc: Call arch-specific hook on discovering KVM services mm/ioremap: Add arch-specific callbacks on ioremap/iounmap calls arm64: Implement ioremap/iounmap hooks calling into KVM's MMIO guard arm64: Enroll into KVM's MMIO guard if required arm64: Add a helper to retrieve the PTE of a fixmap arm64: Register earlycon fixmap with the MMIO guard .../admin-guide/kernel-parameters.txt | 3 + Documentation/virt/kvm/arm/index.rst | 1 + Documentation/virt/kvm/arm/mmio-guard.rst | 73 +++++++++++ arch/arm/include/asm/hypervisor.h | 1 + arch/arm64/include/asm/fixmap.h | 2 + arch/arm64/include/asm/hypervisor.h | 2 + arch/arm64/include/asm/kvm_host.h | 14 ++- arch/arm64/include/asm/kvm_mmu.h | 5 + arch/arm64/include/asm/kvm_pgtable.h | 12 +- arch/arm64/kernel/setup.c | 6 + arch/arm64/kvm/arm.c | 14 ++- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 14 ++- arch/arm64/kvm/hyp/pgtable.c | 36 +++--- arch/arm64/kvm/hypercalls.c | 20 +++ arch/arm64/kvm/mmio.c | 13 +- arch/arm64/kvm/mmu.c | 117 ++++++++++++++++++ arch/arm64/kvm/trace_arm.h | 17 +++ arch/arm64/mm/ioremap.c | 107 ++++++++++++++++ arch/arm64/mm/mmu.c | 15 +++ drivers/firmware/smccc/kvm_guest.c | 4 + include/linux/arm-smccc.h | 28 +++++ include/linux/io.h | 3 + include/uapi/linux/kvm.h | 1 + mm/ioremap.c | 13 +- mm/vmalloc.c | 8 ++ 25 files changed, 492 insertions(+), 37 deletions(-) create mode 100644 Documentation/virt/kvm/arm/mmio-guard.rst -- 2.30.2