From patchwork Wed Jul 19 23:40:02 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Wanpeng Li X-Patchwork-Id: 9853371 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 971FD60392 for ; Wed, 19 Jul 2017 23:40:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 76EDA28705 for ; Wed, 19 Jul 2017 23:40:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6BC3728715; Wed, 19 Jul 2017 23:40:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 224E128705 for ; Wed, 19 Jul 2017 23:40:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933415AbdGSXkP (ORCPT ); Wed, 19 Jul 2017 19:40:15 -0400 Received: from mail-pg0-f65.google.com ([74.125.83.65]:34310 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932202AbdGSXkN (ORCPT ); Wed, 19 Jul 2017 19:40:13 -0400 Received: by mail-pg0-f65.google.com with SMTP id v190so1192288pgv.1; Wed, 19 Jul 2017 16:40:13 -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:mime-version :content-transfer-encoding; bh=vLSIrk3yio0YbxY92V4XVKw+NVfN2T2heJlMRFlTzZU=; b=SRHoafszRhXDPFCHa2DCUTQ3e2BDPL2majS5Jg1JKby1YlEQgeC4VNKQA/S3KatDsH A0Cl2e+OOJkUwvlGQ/t74jsNMiBmI2elE2kmgz2seSdQPbgz45NR2ClNUAizwcoUB2Pk hJgcds7Mv1b9D0s0+A0iBWyU2HJEbGEzMoX154isWOAYr53bA6mekKKLm+HZEB6x5YRw ypSUBxpMTI11WykDccBxFg5Td4Bznz/koYC9zBbE6CEAKOVhCmhBPIWGoObVT5tOX3tt fKmoesH3PTzJGj8BB9h4N9wpGTI0ImJ4diuFzOHWD14HATBncLmqoGNsJuSqxXX4Wdax 46KA== 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:mime-version :content-transfer-encoding; bh=vLSIrk3yio0YbxY92V4XVKw+NVfN2T2heJlMRFlTzZU=; b=PiuQoY+rUQ4jQ1CfauJa7a1X3oeQFFjnmFjiPHgjBXx4iLWhUhIGDHwML2cUl5ew/y sx/rWpof3W4U8fzmRsBeHfXq73ibSVFhizN7lUyMMeZxMqRDYdJR8ndInaR6Gg2GOamg RBbHNZgkba+G7xR3SlsnhdE2Tv6/9Rm55sPnGZbm2NIkJRL8EbUvmq9GrgFXJxwu+Z6t 86035ywstCWYZ0RFF48xJ0w3kVf8cNAeY2sofzSNKRn4XuA5Z3YNm3BCxSsxkGCLZc8j I8GC/MuipIPczdebFmKi/mi2a8s7JfZ2mXNk/mUclOnimPBFC6009LshKGBrL7yYktg/ VGhQ== X-Gm-Message-State: AIVw110p4JrdmFP7mEDhIsfP/vmJ3B5sC0HF2Z4S3kmhfwT8cP+rtBSv YP+jAmjp6O/pXWFL X-Received: by 10.99.105.201 with SMTP id e192mr1821681pgc.158.1500507612952; Wed, 19 Jul 2017 16:40:12 -0700 (PDT) Received: from localhost ([121.35.211.95]) by smtp.gmail.com with ESMTPSA id z29sm1534351pff.50.2017.07.19.16.40.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Jul 2017 16:40:12 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Wanpeng Li , Nadav Amit Subject: [PATCH v2] KVM: VMX: Fix invalid guest state detection after task-switch emulation Date: Wed, 19 Jul 2017 16:40:02 -0700 Message-Id: <1500507602-105830-1-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Wanpeng Li This can be reproduced by EPT=1, unrestricted_guest=N, emulate_invalid_state=Y or EPT=0, the trace of kvm-unit-tests/taskswitch2.flat is like below, it tries to emulate invalid guest state task-switch: kvm_exit: reason TASK_SWITCH rip 0x0 info 40000058 0 kvm_emulate_insn: 42000:0:0f 0b (0x2) kvm_emulate_insn: 42000:0:0f 0b (0x2) failed kvm_inj_exception: #UD (0x0) kvm_entry: vcpu 0 kvm_exit: reason TASK_SWITCH rip 0x0 info 40000058 0 kvm_emulate_insn: 42000:0:0f 0b (0x2) kvm_emulate_insn: 42000:0:0f 0b (0x2) failed kvm_inj_exception: #UD (0x0) ...................... It appears that the task-switch emulation updates rflags (and vm86 flag) only after the segments are loaded, causing vmx->emulation_required to be set, when in fact invalid guest state emulation is not needed. This patch fixes it by updating vmx->emulation_required after the rflags (and vm86 flag) is updated in task-switch emulation. Thanks Radim for moving the update to vmx__set_flags and adding Paolo's suggestion for the check. Suggested-by: Nadav Amit Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Nadav Amit Signed-off-by: Wanpeng Li --- arch/x86/kvm/vmx.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 84e62ac..287639e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2326,6 +2326,11 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu) __vmx_load_host_state(to_vmx(vcpu)); } +static bool emulation_required(struct kvm_vcpu *vcpu) +{ + return emulate_invalid_guest_state && !guest_state_valid(vcpu); +} + static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu); /* @@ -2363,6 +2368,9 @@ static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu) static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) { + unsigned long old_rflags = vmx_get_rflags(vcpu); + unsigned long save_rflags = rflags; + __set_bit(VCPU_EXREG_RFLAGS, (ulong *)&vcpu->arch.regs_avail); to_vmx(vcpu)->rflags = rflags; if (to_vmx(vcpu)->rmode.vm86_active) { @@ -2370,6 +2378,9 @@ static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) rflags |= X86_EFLAGS_IOPL | X86_EFLAGS_VM; } vmcs_writel(GUEST_RFLAGS, rflags); + + if ((old_rflags ^ save_rflags) & X86_EFLAGS_VM) + to_vmx(vcpu)->emulation_required = emulation_required(vcpu); } static u32 vmx_get_pkru(struct kvm_vcpu *vcpu) @@ -3857,11 +3868,6 @@ static __init int alloc_kvm_area(void) return 0; } -static bool emulation_required(struct kvm_vcpu *vcpu) -{ - return emulate_invalid_guest_state && !guest_state_valid(vcpu); -} - static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg, struct kvm_segment *save) {