From patchwork Fri Jul 22 01:50:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Collingbourne X-Patchwork-Id: 12925871 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C1303C433EF for ; Fri, 22 Jul 2022 01:52:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Mime-Version: Message-Id:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=HOVg8hl9nEDTt7ytHrXzgzdHEoXEoZRirGtduIxCU4Y=; b=Z3x NR2t9/5Z1I59hO5/DHA9rFSH5SfUa53vHzGHezfDGjBq5Yp3G+AmzuH6tmqrlD5tiniSVz1rItgek 00mAZTB0kNwcuIKHK+EvMckhn9GlDcZrYzGmkT1H+ZXlBKESxqRnVB2W0SP3MO6k65a4gjh4FyQFa L8Pf1His4nyFDqyT26v9IwG6JKjxXWSyzFQYnyWOkX5NtuPwvcfKswHC5PtG9z8wKDokO8KlTadsP 3isxwmlgOuGuGS37S577FL5/NEQzA2WomC2Gtu3ssSNP0T/Q1+6bguhGA5LiDbNlT6XiE7SoNUL6d QVcQkSEAVgymaklHoZ0a0ZoS1VKFT5A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oEhoi-00FlaY-3E; Fri, 22 Jul 2022 01:51:00 +0000 Received: from mail-yw1-x114a.google.com ([2607:f8b0:4864:20::114a]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oEhoe-00FlH5-Ht for linux-arm-kernel@lists.infradead.org; Fri, 22 Jul 2022 01:50:58 +0000 Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-31e55518830so28653577b3.23 for ; Thu, 21 Jul 2022 18:50:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=Rhs+4jBfg1QM5n7eWG2/LdEIc5IyIGfWAsCL7NyPRwQ=; b=EPu9cfSmX3DAmdVD3SXg5Chipd7twxc2aYzKZWGdt9qqZYcXxOhVbYsm2Q4w3Keblq iOOY371rfBqvXTY6NybNQWreMp53L+rUZ1LTcNZne4JJDGcvaPks3Ru8OFBCCz30Qmwx 4WD270XRYhRv/GvT+dVV1awsfHaNxwtD37r68MFhp9ELCmrImgLiyWRhaKkWDXkBoZnH s78qnShu3Azqth50MftuCULbQDS0/sGtGm8g1LRAArzgephpOZ9rxfyCLFfTxD4ZvsHo W0x7N5i+Yoy5MqKgYCuj6TnY2HyvX9xkkG6z1rNzJUm68C/cjwlYxsZY/ACE2sHzBlDO jhcQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=Rhs+4jBfg1QM5n7eWG2/LdEIc5IyIGfWAsCL7NyPRwQ=; b=aJQnR54k7WJ7MRN6cQEpKQ85dneFQUkzmpJgyt1Z1Fv+95k9suDnG+5dGyFnlBuVoF OLz008lavbxcZgqsPIcDOoPnPTa1mZ+aMnIHLG9eLOoFduJNNLWYRN3EICFNd4LjwTpU rJKS+iyuYLKXJ40c2EdwUqMhtdT1zrp+6/BQ4xYM151hzuRGW9Ks9ZIthtqfmSPITxss MkaADx5ZwDyI3Cx+Hr2qAZiPJ5fFvevHMc6seNZG/JVNPNMqsHTc/uzYtxPgCAXI+pZJ rYEy6M3J+zhJm19WUZUBt63ZGhrMf6LgLYiP3jof6RRC2JUGcMeDOOXE1KPtxiBZDJKg oseQ== X-Gm-Message-State: AJIora9VJvL2gNKCSf68Fpqc8qVYloR0eIzHsKlPYI9ErDIZLtCBBuKK /13p5a91ECL5H1Zni1KotiRNDsuSmwaCSjJgS/qV5RrMpplLFK2yysSMPhbconEaKXVYzqInZ3y dRdc5cSs5miq+H0MopBNyoEvBXYiYtmegMAQfpoCZ5FKqkU/KTWoXWHxbLYZjWCz/26P0IiLI X-Google-Smtp-Source: AGRyM1s/pmWLb7/RVeSHgBd1PqQYRVoHVPsujzJ6L2UtPXkGfO1tJ3J+fcjlJoTgQYjpaF7llAnRI+U= X-Received: from pcc-desktop.svl.corp.google.com ([2620:15c:2ce:200:7ed4:5864:d5e1:ffe1]) (user=pcc job=sendgmr) by 2002:a5b:890:0:b0:670:8312:a52f with SMTP id e16-20020a5b0890000000b006708312a52fmr1197181ybq.139.1658454654329; Thu, 21 Jul 2022 18:50:54 -0700 (PDT) Date: Thu, 21 Jul 2022 18:50:26 -0700 Message-Id: <20220722015034.809663-1-pcc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.37.1.359.gd136c6c3e2-goog Subject: [PATCH v2 0/7] KVM: arm64: permit MAP_SHARED mappings with MTE enabled From: Peter Collingbourne To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Cc: Peter Collingbourne , Cornelia Huck , Catalin Marinas , Will Deacon , Marc Zyngier , Evgenii Stepanov , kvm@vger.kernel.org, Steven Price , Vincenzo Frascino X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220721_185056_621707_CD6CFB96 X-CRM114-Status: GOOD ( 23.54 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, This patch series allows VMMs to use shared mappings in MTE enabled guests. The first four patches are based on the series that Catalin sent out, whose cover letter [1] I quote from below: > This series aims to fix the races between initialising the tags on a > page and setting the PG_mte_tagged flag. Currently the flag is set > either before or after that tag initialisation and this can lead to CoW > copying stale tags. The first patch moves the flag setting after the > tags have been initialised, solving the CoW issue. However, concurrent > mprotect() on a shared mapping may (very rarely) lead to valid tags > being zeroed. > > The second skips the sanitise_mte_tags() call in kvm_set_spte_gfn(), > deferring it to user_mem_abort(). The outcome is that no > sanitise_mte_tags() can be simplified to skip the pfn_to_online_page() > check and only rely on VM_MTE_ALLOWED vma flag that can be checked in > user_mem_abort(). > > The third and fourth patches use PG_arch_3 as a lock for page tagging, > based on Peter Collingbourne's idea of a two-bit lock. > > I think the first patch can be queued but the rest needs some in depth > review and test. With this series (if correct) we could allos MAP_SHARED > on KVM guest memory but this is to be discussed separately as there are > some KVM ABI implications. I rebased Catalin's series onto -next, addressed the issues that I identified in the review and added the proposed userspace enablement patches after the series. [1] https://lore.kernel.org/all/20220705142619.4135905-1-catalin.marinas@arm.com/ Catalin Marinas (3): arm64: mte: Fix/clarify the PG_mte_tagged semantics KVM: arm64: Simplify the sanitise_mte_tags() logic arm64: mte: Lock a page for MTE tag initialisation Peter Collingbourne (4): mm: Add PG_arch_3 page flag KVM: arm64: unify the tests for VMAs in memslots when MTE is enabled KVM: arm64: permit all VM_MTE_ALLOWED mappings with MTE enabled Documentation: document the ABI changes for KVM_CAP_ARM_MTE Documentation/virt/kvm/api.rst | 5 +-- arch/arm64/include/asm/mte.h | 62 ++++++++++++++++++++++++++++++++ arch/arm64/include/asm/pgtable.h | 3 +- arch/arm64/kernel/cpufeature.c | 4 ++- arch/arm64/kernel/elfcore.c | 2 +- arch/arm64/kernel/hibernate.c | 2 +- arch/arm64/kernel/mte.c | 17 +++++---- arch/arm64/kvm/guest.c | 18 ++++++---- arch/arm64/kvm/mmu.c | 55 ++++++++++++---------------- arch/arm64/mm/copypage.c | 6 ++-- arch/arm64/mm/fault.c | 4 ++- arch/arm64/mm/mteswap.c | 5 ++- fs/proc/page.c | 1 + include/linux/page-flags.h | 1 + include/trace/events/mmflags.h | 7 ++-- mm/huge_memory.c | 1 + 16 files changed, 134 insertions(+), 59 deletions(-)