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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 3937CC433E0 for ; Tue, 29 Dec 2020 07:19:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F2C72220F for ; Tue, 29 Dec 2020 07:19:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726173AbgL2HTK (ORCPT ); Tue, 29 Dec 2020 02:19:10 -0500 Received: from mga04.intel.com ([192.55.52.120]:11855 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725767AbgL2HTK (ORCPT ); Tue, 29 Dec 2020 02:19:10 -0500 IronPort-SDR: kJgi/DFXkXKTzu65gduZgNlOhGsHoRACROFXvp8dLh9jbqwt2sHuMZEmIiO69tPaiyK7UbjWAN Bob+yjabg4dQ== X-IronPort-AV: E=McAfee;i="6000,8403,9848"; a="173888152" X-IronPort-AV: E=Sophos;i="5.78,457,1599548400"; d="scan'208";a="173888152" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Dec 2020 23:17:25 -0800 IronPort-SDR: QKCKIStYkeNmfJgKwwFY1lbNsImWFJP+blXuQKbjL2cbTrl2SQEqqYBlWswOBNA1LnXwYwDFyL u5/2oMz8bZjg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,457,1599548400"; d="scan'208";a="347286495" Received: from unknown (HELO clx-ap-likexu.sh.intel.com) ([10.239.48.105]) by fmsmga008.fm.intel.com with ESMTP; 28 Dec 2020 23:17:23 -0800 From: Like Xu To: Paolo Bonzini , Sean Christopherson Cc: syzkaller-bugs@googlegroups.com, Vitaly Kuznetsov , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, Wanpeng Li , linux-kernel@vger.kernel.org Subject: [PATCH] KVM: x86/pmu: Fix UBSAN shift-out-of-bounds warning in intel_pmu_refresh() Date: Tue, 29 Dec 2020 15:11:44 +0800 Message-Id: <20201229071144.85418-1-like.xu@linux.intel.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Since we know vPMU will not work properly when the guest bit_width(s) of the [gp|fixed] counters are greater than the host ones, so we can setup a smaller left shift value and refresh the guest pmu cpuid entry, thus fixing the following UBSAN shift-out-of-bounds warning: shift exponent 197 is too large for 64-bit type 'long long unsigned int' Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395 intel_pmu_refresh.cold+0x75/0x99 arch/x86/kvm/vmx/pmu_intel.c:348 kvm_vcpu_after_set_cpuid+0x65a/0xf80 arch/x86/kvm/cpuid.c:177 kvm_vcpu_ioctl_set_cpuid2+0x160/0x440 arch/x86/kvm/cpuid.c:308 kvm_arch_vcpu_ioctl+0x11b6/0x2d70 arch/x86/kvm/x86.c:4709 kvm_vcpu_ioctl+0x7b9/0xdb0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3386 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported-by: syzbot+ae488dc136a4cc6ba32b@syzkaller.appspotmail.com Signed-off-by: Like Xu --- arch/x86/kvm/vmx/pmu_intel.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index a886a47daebd..a86a1690e75c 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -345,6 +345,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters, x86_pmu.num_counters_gp); + eax.split.bit_width = min_t(int, eax.split.bit_width, x86_pmu.bit_width_gp); pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1; pmu->available_event_types = ~entry->ebx & ((1ull << eax.split.mask_length) - 1); @@ -355,6 +356,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->nr_arch_fixed_counters = min_t(int, edx.split.num_counters_fixed, x86_pmu.num_counters_fixed); + edx.split.bit_width_fixed = min_t(int, + edx.split.bit_width_fixed, x86_pmu.bit_width_fixed); pmu->counter_bitmask[KVM_PMC_FIXED] = ((u64)1 << edx.split.bit_width_fixed) - 1; } -- 2.29.2