From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751187AbdHVQKD (ORCPT ); Tue, 22 Aug 2017 12:10:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34188 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751043AbdHVQKC (ORCPT ); Tue, 22 Aug 2017 12:10:02 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CE797267E0 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=pbonzini@redhat.com Subject: Re: [PATCH v3] KVM: nVMX: Fix trying to cancel vmlauch/vmresume To: Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Wanpeng Li References: <1503356912-117219-1-git-send-email-wanpeng.li@hotmail.com> From: Paolo Bonzini Message-ID: <0467288d-1e3d-0ea0-dd8a-c034dcac6ee1@redhat.com> Date: Tue, 22 Aug 2017 18:09:58 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1503356912-117219-1-git-send-email-wanpeng.li@hotmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 22 Aug 2017 16:10:01 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/08/2017 01:08, Wanpeng Li wrote: > From: Wanpeng Li > > ------------[ cut here ]------------ > WARNING: CPU: 7 PID: 3861 at /home/kernel/ssd/kvm/arch/x86/kvm//vmx.c:11299 nested_vmx_vmexit+0x176e/0x1980 [kvm_intel] > CPU: 7 PID: 3861 Comm: qemu-system-x86 Tainted: G W OE 4.13.0-rc4+ #11 > RIP: 0010:nested_vmx_vmexit+0x176e/0x1980 [kvm_intel] > Call Trace: > ? kvm_multiple_exception+0x149/0x170 [kvm] > ? handle_emulation_failure+0x79/0x230 [kvm] > ? load_vmcs12_host_state+0xa80/0xa80 [kvm_intel] > ? check_chain_key+0x137/0x1e0 > ? reexecute_instruction.part.168+0x130/0x130 [kvm] > nested_vmx_inject_exception_vmexit+0xb7/0x100 [kvm_intel] > ? nested_vmx_inject_exception_vmexit+0xb7/0x100 [kvm_intel] > vmx_queue_exception+0x197/0x300 [kvm_intel] > kvm_arch_vcpu_ioctl_run+0x1b0c/0x2c90 [kvm] > ? kvm_arch_vcpu_runnable+0x220/0x220 [kvm] > ? preempt_count_sub+0x18/0xc0 > ? restart_apic_timer+0x17d/0x300 [kvm] > ? kvm_lapic_restart_hv_timer+0x37/0x50 [kvm] > ? kvm_arch_vcpu_load+0x1d8/0x350 [kvm] > kvm_vcpu_ioctl+0x4e4/0x910 [kvm] > ? kvm_vcpu_ioctl+0x4e4/0x910 [kvm] > ? kvm_dev_ioctl+0xbe0/0xbe0 [kvm] > > The flag "nested_run_pending", which can override the decision of which should run > next, L1 or L2. nested_run_pending=1 means that we *must* run L2 next, not L1. This > is necessary in particular when L1 did a VMLAUNCH of L2 and therefore expects L2 to > be run (and perhaps be injected with an event it specified, etc.). Nested_run_pending > is especially intended to avoid switching to L1 in the injection decision-point. > > I catch this in the queue exception path, this patch fixes it by running L2 next > instead of L1 in the queue exception path and injecting the pending exception to > L2 directly. > > Cc: Paolo Bonzini > Cc: Radim Krčmář > Signed-off-by: Wanpeng Li > --- > v2 -> v3: > * move the nested_run_pending to the else branch > v1 -> v2: > * request an immediate VM exit from L2 and keep the exception for > L1 pending for a subsequent nested VM exit > > arch/x86/kvm/vmx.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index e398946..685f51e 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -2488,6 +2488,10 @@ static int nested_vmx_check_exception(struct kvm_vcpu *vcpu) > } > } else { > unsigned long exit_qual = 0; > + > + if (to_vmx(vcpu)->nested.nested_run_pending) > + return 0; > + > if (nr == DB_VECTOR) > exit_qual = vcpu->arch.dr6; > > Hmm, why would this not apply to page faults? It doesn't make much sense... Paolo