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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 7A5D6C0650E for ; Mon, 1 Jul 2019 08:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 49D1E20673 for ; Mon, 1 Jul 2019 08:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727508AbfGAIDk (ORCPT ); Mon, 1 Jul 2019 04:03:40 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:39820 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726036AbfGAIDj (ORCPT ); Mon, 1 Jul 2019 04:03:39 -0400 Received: from pd9ef1cb8.dip0.t-ipconnect.de ([217.239.28.184] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1hhrHd-0000IT-DL; Mon, 01 Jul 2019 10:03:29 +0200 Date: Mon, 1 Jul 2019 10:03:28 +0200 (CEST) From: Thomas Gleixner To: Li Wang cc: ricardo.neri-calderon@linux.intel.com, pbonzini@redhat.com, kernellwp@gmail.com, ricardo.neri@intel.com, pengfei.xu@intel.com, LTP List , linux-kernel , Ping Fang Subject: Re: [Kernel BUG?] SMSW operation get success on UMIP KVM guest In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 1 Jul 2019, Li Wang wrote: > Hello there, > > LTP/umip_basic_test get failed on KVM UMIP system(kernel-v5.2-rc4.x86_64). > The test is only trying to do > asm volatile("smsw %0\n" : "=m" (val)); > and expect to get SIGSEGV in this SMSW operation, but it exits with 0 > unexpectedly. > > ==================== > # grep CONFIG_X86_INTEL_UMIP /boot/config-5.2.0-0.rc4.x86_64 > CONFIG_X86_INTEL_UMIP=y > > # lscpu |grep umip > Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge > mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp > lm constant_tsc rep_good nopl xtopology cpuid tsc_known_freq pni pclmulqdq > ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer > aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault > invpcid_single pti ssbd ibrs ibpb stibp fsgsbase tsc_adjust bmi1 hle avx2 > smep bmi2 erms invpcid rtm mpx avx512f avx512dq rdseed adx smap clflushopt > clwb avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves arat umip > pku ospke md_clear > > # ./umip_basic_test > ... > umip_basic_test.c:68: INFO: TEST smsw, smsw result save at [0x7ffda00dca70] > umip_basic_test.c:118: FAIL: Didn't receive SIGSEGV, child exited with > exited with 0 SMSW is emulated and returns a constant value: #define CR0_STATE (X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \ X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \ X86_CR0_PG) IIRC that is done to not break stuff like Wine. Ricardo should know the details. Thanks, tglx