From patchwork Fri May 28 00:01:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wanpeng Li X-Patchwork-Id: 12285805 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 83598C47089 for ; Fri, 28 May 2021 00:02:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AF2B611C9 for ; Fri, 28 May 2021 00:02:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235849AbhE1AEH (ORCPT ); Thu, 27 May 2021 20:04:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235696AbhE1AEF (ORCPT ); Thu, 27 May 2021 20:04:05 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC675C061574; Thu, 27 May 2021 17:02:29 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id f8so1539776pjh.0; Thu, 27 May 2021 17:02:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=NrZavczs0MF8tqdeaU/rr2uBfm1FCnanDV4vtlGL8eQ=; b=BGP08nCqsa2o3kZ9ZJeK95PtCPZwmjIlwuRj/1GAbtQ9m4JMjbAFHpv1b+nw1LZYfg 7lDBGS9RdNenHYktTGzz+cJsGKrcReYpj+dGcXgmXoDfq/WVXt/A1jlAFC0rZO1nZf8a zfio6Q18LToGNbzBAc1tt8gpmTgQAmkHLJV9l5L+lMHDKejr1HvqZmcEnyz/QAbt8ovc 5EP4cWIUUa1xPnsM4Q+sejEdr0ec1Ar6YtQoY9kalwzdt1QuDJXafnv8U+yWFAzyG/P1 +mu0wTMYxxr9erWga4Efd/AxH3MPUnSGIxtrwKhOoMfiiJaszekCKoBxIrrh+q3DesM0 cPQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=NrZavczs0MF8tqdeaU/rr2uBfm1FCnanDV4vtlGL8eQ=; b=ZOCT935RchZNzEVfGcbbrDfA5ETogpQQug7ifQp5egdeFGRDJISlZ+u1wnJu1/2WxM vk9rNLbtFNWn6w+p6/Nv/rdkWPmzaaCqzYmxJxzXqEOlxME7uzb2ssCHBhmhJRT9z6yr jwNzneiHajuih1eX1J2iXpmyorLoFYuJRc5XNW/PgZnE3AC7UH6TcxPyMq39IzsGXNOa 78OTfagVBhWPVMGE4pZ1qDUd2KReZSWfRHcVnr70BzIzFyYq6UPz4nbzfXKhIAvdAwfe UjwuDNbScRPs4D5EWP0TAi7bb0Tb/+2RJKhbDkswxfJFfFpSZ/+1VwnSJnDifAM63ebA BX6A== X-Gm-Message-State: AOAM530FlZGU++IT0YGo6xar10HWKjIdDVwXbhqRJxDYhouxFeLbYsJ9 pjWz0em4B95NlOO0PPzBG0A5SUdCjCw= X-Google-Smtp-Source: ABdhPJylwVntfhyEImkOcMhIXJJySVS5uZe3jihEgU3SrdOXEH8ipfurtx5JzV+a8xDLMsGEUd/PSQ== X-Received: by 2002:a17:902:265:b029:fa:9420:d2fd with SMTP id 92-20020a1709020265b02900fa9420d2fdmr5462176plc.39.1622160148947; Thu, 27 May 2021 17:02:28 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.56]) by smtp.googlemail.com with ESMTPSA id l126sm2726245pga.41.2021.05.27.17.02.26 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 May 2021 17:02:28 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Subject: [PATCH v4 1/2] KVM: X86: Fix warning caused by stale emulation context Date: Thu, 27 May 2021 17:01:36 -0700 Message-Id: <1622160097-37633-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Wanpeng Li Reported by syzkaller: WARNING: CPU: 7 PID: 10526 at linux/arch/x86/kvm//x86.c:7621 x86_emulate_instruction+0x41b/0x510 [kvm] RIP: 0010:x86_emulate_instruction+0x41b/0x510 [kvm] Call Trace: kvm_mmu_page_fault+0x126/0x8f0 [kvm] vmx_handle_exit+0x11e/0x680 [kvm_intel] vcpu_enter_guest+0xd95/0x1b40 [kvm] kvm_arch_vcpu_ioctl_run+0x377/0x6a0 [kvm] kvm_vcpu_ioctl+0x389/0x630 [kvm] __x64_sys_ioctl+0x8e/0xd0 do_syscall_64+0x3c/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Commit 4a1e10d5b5d8 ("KVM: x86: handle hardware breakpoints during emulation()) adds hardware breakpoints check before emulation the instruction and parts of emulation context initialization, actually we don't have the EMULTYPE_NO_DECODE flag here and the emulation context will not be reused. Commit c8848cee74ff ("KVM: x86: set ctxt->have_exception in x86_decode_insn()) triggers the warning because it catches the stale emulation context has #UD, however, it is not during instruction decoding which should result in EMULATION_FAILED. This patch fixes it by moving the second part emulation context initialization into init_emulate_ctxt() and before hardware breakpoints check. The ctxt->ud will be dropped by a follow-up patch. syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=134683fdd00000 Reported-by: syzbot+71271244f206d17f6441@syzkaller.appspotmail.com Fixes: 4a1e10d5b5d8 (KVM: x86: handle hardware breakpoints during emulation) Signed-off-by: Wanpeng Li Reviewed-by: Sean Christopherson --- v3 -> v4: * warning relative path * not move ctxt->ud v2 -> v3: * squash ctxt->ud v1 -> v2: * move the second part emulation context initialization into init_emulate_ctxt() arch/x86/kvm/x86.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bbc4e04..dba8077 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7226,6 +7226,11 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu) BUILD_BUG_ON(HF_SMM_MASK != X86EMUL_SMM_MASK); BUILD_BUG_ON(HF_SMM_INSIDE_NMI_MASK != X86EMUL_SMM_INSIDE_NMI_MASK); + ctxt->interruptibility = 0; + ctxt->have_exception = false; + ctxt->exception.vector = -1; + ctxt->perm_ok = false; + init_decode_cache(ctxt); vcpu->arch.emulate_regs_need_sync_from_vcpu = false; } @@ -7561,11 +7566,6 @@ int x86_decode_emulated_instruction(struct kvm_vcpu *vcpu, int emulation_type, kvm_vcpu_check_breakpoint(vcpu, &r)) return r; - ctxt->interruptibility = 0; - ctxt->have_exception = false; - ctxt->exception.vector = -1; - ctxt->perm_ok = false; - ctxt->ud = emulation_type & EMULTYPE_TRAP_UD; r = x86_decode_insn(ctxt, insn, insn_len); From patchwork Fri May 28 00:01:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wanpeng Li X-Patchwork-Id: 12285807 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 4A7ABC4708B for ; Fri, 28 May 2021 00:02:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28EED613D1 for ; Fri, 28 May 2021 00:02:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235937AbhE1AE3 (ORCPT ); Thu, 27 May 2021 20:04:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235905AbhE1AEH (ORCPT ); Thu, 27 May 2021 20:04:07 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B426AC061574; Thu, 27 May 2021 17:02:32 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id ep16-20020a17090ae650b029015d00f578a8so1489912pjb.2; Thu, 27 May 2021 17:02:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=SeFLBMDAzUrHuAE4pyFWQsjz2vLHikZIPIbOi3aXJRY=; b=CKb+NO3Gk54mgnmoEzsQL7aKkPTIg5FavdZK4Rhmrcam7EGIbYZ02VyNUZKcky8mu/ 8LWcxxn7++Ts1Dz365SF9DYs4EJL5zTX3ygEH0UPKreOH/8E8tnWl7JgV5e0d2KfFPZX oEGoAee0mhY24cijXV6sGzgg80QQOS/orWxYU6yYWvVoChNvhTMFEODrNJ8p7oS5dVaC tupWiz08CacShghQOIo39pIRnIwMrW2ZCvX7BiaI6GtHq+DVw0EQOW3oqU29VwK0Is3n 1SVBxfSGVTgT7vAIh8DpwouKuHIQ30/pYy5vaKObaK+BBVAKTrLj7jJifwUwh6bU15FC uMvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=SeFLBMDAzUrHuAE4pyFWQsjz2vLHikZIPIbOi3aXJRY=; b=A7t8nJnk0sHHV0OePpQMy/HrHOGUuF7oditXTSbhPG6DQN7Dq11Pg401PFkRG7WMjU rWIeeQCFHcYpBVk+nCJDFobwan1aqUKdjsdotXbkeYm1ibHWe0GKnEHjycaCT4mCo+ir lMADctB4LptR2fD4E7PdqF88LQrribRG/PsxEqr+7NUc7QyVVOeBCV3GxBMAOmQnN9Jm KiMaAtkK0ihH4+2RvrsNL7wmHmB7eybJRQos84NuMNmvEVRxoXGoizusJT7STwEijl14 y/5272AYi0jYAxS0Y0wSZrt8/IEGF+1DxczKpuMBDrDFWjJWD/511VPFXusRSWL8RG2Z 0vpg== X-Gm-Message-State: AOAM5322D6KHD/N7qAU4sAzXlI6C2uCNXoDx1VfXuHpnGxQ6rl92Ve36 FL5N/Eeew1Jdx/L8i96R1BhKRmkozgw= X-Google-Smtp-Source: ABdhPJxdS2H2V1t0rm57l4hxI6q0xWG8U+Cu3Q5eunWX4qMMDDGS228qYrphOmEawfZRP9mM9ZOm8w== X-Received: by 2002:a17:903:230b:b029:f4:b7cf:44aa with SMTP id d11-20020a170903230bb02900f4b7cf44aamr5404262plh.31.1622160151952; Thu, 27 May 2021 17:02:31 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.56]) by smtp.googlemail.com with ESMTPSA id l126sm2726245pga.41.2021.05.27.17.02.29 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 May 2021 17:02:31 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Subject: [PATCH v4 2/2] KVM: X86: Kill off ctxt->ud Date: Thu, 27 May 2021 17:01:37 -0700 Message-Id: <1622160097-37633-2-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1622160097-37633-1-git-send-email-wanpengli@tencent.com> References: <1622160097-37633-1-git-send-email-wanpengli@tencent.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Wanpeng Li ctxt->ud is consumed only by x86_decode_insn(), we can kill it off by passing emulation_type to x86_decode_insn() and dropping ctxt->ud altogether. Tracking that info in ctxt for literally one call is silly. Suggested-by: Sean Christopherson Signed-off-by: Wanpeng Li Reviewed-by: Sean Christopherson --- arch/x86/kvm/emulate.c | 5 +++-- arch/x86/kvm/kvm_emulate.h | 3 +-- arch/x86/kvm/x86.c | 4 +--- 3 files changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 8a0ccdb..5e5de05 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5111,7 +5111,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, return rc; } -int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) +int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int emulation_type) { int rc = X86EMUL_CONTINUE; int mode = ctxt->mode; @@ -5322,7 +5322,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) ctxt->execute = opcode.u.execute; - if (unlikely(ctxt->ud) && likely(!(ctxt->d & EmulateOnUD))) + if (unlikely(emulation_type & EMULTYPE_TRAP_UD) && + likely(!(ctxt->d & EmulateOnUD))) return EMULATION_FAILED; if (unlikely(ctxt->d & diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index f016838..3e870bf 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -314,7 +314,6 @@ struct x86_emulate_ctxt { int interruptibility; bool perm_ok; /* do not check permissions if true */ - bool ud; /* inject an #UD if host doesn't support insn */ bool tf; /* TF value before instruction (after for syscall/sysret) */ bool have_exception; @@ -491,7 +490,7 @@ enum x86_intercept { #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 #endif -int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len); +int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int emulation_type); bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt); #define EMULATION_FAILED -1 #define EMULATION_OK 0 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dba8077..d752345 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7566,9 +7566,7 @@ int x86_decode_emulated_instruction(struct kvm_vcpu *vcpu, int emulation_type, kvm_vcpu_check_breakpoint(vcpu, &r)) return r; - ctxt->ud = emulation_type & EMULTYPE_TRAP_UD; - - r = x86_decode_insn(ctxt, insn, insn_len); + r = x86_decode_insn(ctxt, insn, insn_len, emulation_type); trace_kvm_emulate_insn_start(vcpu); ++vcpu->stat.insn_emulation;