From patchwork Fri Aug 20 22:49:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 500706 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=-21.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 A4B0FC4320E for ; Fri, 20 Aug 2021 22:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B61F601FE for ; Fri, 20 Aug 2021 22:50:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231482AbhHTWvE (ORCPT ); Fri, 20 Aug 2021 18:51:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232349AbhHTWvD (ORCPT ); Fri, 20 Aug 2021 18:51:03 -0400 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 149D8C061760 for ; Fri, 20 Aug 2021 15:50:25 -0700 (PDT) Received: by mail-qk1-x74a.google.com with SMTP id g73-20020a379d4c000000b003d3ed03ca28so7398412qke.23 for ; Fri, 20 Aug 2021 15:50:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=reply-to:date:message-id:mime-version:subject:from:to:cc; bh=gyS/18bxD5Ot3om3ClN1RHHdw6uDm46TAPmhFRClN7E=; b=c0x2Ekl31aHgoUr6bS0aBngW8SrcCyXGQ6Eg5RkenHrpLPuk61rKOt6P1SLL5kGpCV 7Q/hwVqrOW+gQ/v3K19SjHlrik6vUlVurzVNjzrPZuy8yaIJYuxpQBictxecVo5Nq+kp 75zG8M002Kjp/q5WlQpL9i9sO4ZrKNxIQavsXfw2HehYTn5oog/nQS8x/qaEbhMPUOUM ccXmKxYBcJpZ+gmTSFvQXJWzizQ+B84f2u2Q9D1+hN2pszPtrQntT2CFvtwN7i4kDteh N7lB2iyqekXxnNmmaDxg+oJ9mOUY3XV5hIyhddm0GtJ4OgnYpsgomnp8ihDtrwm3h+GE x/ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:reply-to:date:message-id:mime-version:subject :from:to:cc; bh=gyS/18bxD5Ot3om3ClN1RHHdw6uDm46TAPmhFRClN7E=; b=GjNQRxYSC731/MTfw20gxZO3ukEwkES0/+jawsXXiJ+54msCxrzdp1xG6wcsogmtF2 OfVVuBY5N2n9Knxm8PmCLNXoPqtwRuTdzLncL4t86BU0PBqm0DaVDcfcT5CY0OBwch3j bB3TIsZThVJkt937UwC5xUDpTPOYFUeCd68qfpsV5B1f9MEpE8aoLt4W1V8s2FrGitt0 h6PXGAkLrHuIuXh1NeROUhzgzIt8jg2EAscadcRTi8idCmQpnpLb08zvIP0E5IS+0e8z s2Sy8CX1r94SazoOrnkY39eHi4EN2jg8T4gSKldDGkvVf8gbclEssyzHUd6omT8U4lNM Y/tQ== X-Gm-Message-State: AOAM533mR70FOlQWD+Y2QOARuXKXRTwkf4TpSdweMWlj3jwZlR1vmSUi ek6rCzbbrbdqLZmsKRYr4udOZSQykE4= X-Google-Smtp-Source: ABdhPJx4goZRGT6Tb8tV1HHxrF56PXshejmS+qu7yC6GJihmWv/bHnUoawuFayGttP22JtXzBIs2h2vWzkY= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:f11d:a281:af9b:5de6]) (user=seanjc job=sendgmr) by 2002:a05:6214:ca2:: with SMTP id s2mr22615169qvs.35.1629499824082; Fri, 20 Aug 2021 15:50:24 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 20 Aug 2021 15:49:57 -0700 Message-Id: <20210820225002.310652-1-seanjc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.33.0.rc2.250.ged5fa647cd-goog Subject: [PATCH v2 0/5] KVM: rseq: Fix and a test for a KVM+rseq bug From: Sean Christopherson To: Russell King , Catalin Marinas , Will Deacon , Guo Ren , Thomas Bogendoerfer , Michael Ellerman , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Steven Rostedt , Ingo Molnar , Oleg Nesterov , Thomas Gleixner , Peter Zijlstra , Andy Lutomirski , Mathieu Desnoyers , "Paul E. McKenney" , Boqun Feng , Paolo Bonzini , Shuah Khan Cc: Benjamin Herrenschmidt , Paul Mackerras , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Peter Foley , Shakeel Butt , Sean Christopherson , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Patch 1 fixes a KVM+rseq bug where KVM's handling of TIF_NOTIFY_RESUME, e.g. for task migration, clears the flag without informing rseq and leads to stale data in userspace's rseq struct. Patch 2 is a cleanup to try and make future bugs less likely. It's also a baby step towards moving and renaming tracehook_notify_resume() since it has nothing to do with tracing. Patch 3 is a fix/cleanup to stop overriding x86's unistd_{32,64}.h when the include path (intentionally) omits tools' uapi headers. KVM's selftests do exactly that so that they can pick up the uapi headers from the installed kernel headers, and still use various tools/ headers that mirror kernel code, e.g. linux/types.h. This allows the new test in patch 4 to reference __NR_rseq without having to manually define it. Patch 4 is a regression test for the KVM+rseq bug. Patch 5 is a cleanup made possible by patch 3. v2: - Don't touch rseq_cs when handling KVM case so that rseq_syscall() will still detect a naughty userspace. [Mathieu] - Use a sequence counter + retry in the test to ensure the process isn't migrated between sched_getcpu() and reading rseq.cpu_id, i.e. to avoid a flaky test. [Mathieu] - Add Mathieu's ack for patch 2. - Add more comments in the test. v1: https://lkml.kernel.org/r/20210818001210.4073390-1-seanjc@google.com Sean Christopherson (5): KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume() tools: Move x86 syscall number fallbacks to .../uapi/ KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs KVM: selftests: Remove __NR_userfaultfd syscall fallback arch/arm/kernel/signal.c | 1 - arch/arm64/kernel/signal.c | 1 - arch/csky/kernel/signal.c | 4 +- arch/mips/kernel/signal.c | 4 +- arch/powerpc/kernel/signal.c | 4 +- arch/s390/kernel/signal.c | 1 - include/linux/tracehook.h | 2 + kernel/entry/common.c | 4 +- kernel/rseq.c | 14 +- .../x86/include/{ => uapi}/asm/unistd_32.h | 0 .../x86/include/{ => uapi}/asm/unistd_64.h | 3 - tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 3 + tools/testing/selftests/kvm/rseq_test.c | 154 ++++++++++++++++++ 14 files changed, 175 insertions(+), 21 deletions(-) rename tools/arch/x86/include/{ => uapi}/asm/unistd_32.h (100%) rename tools/arch/x86/include/{ => uapi}/asm/unistd_64.h (83%) create mode 100644 tools/testing/selftests/kvm/rseq_test.c Acked-by: Mathieu Desnoyers Reviewed-by: Ben Gardon