Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753295AbaGBJDk (ORCPT ); Wed, 2 Jul 2014 05:03:40 -0400 Received: from goliath.siemens.de ([192.35.17.28]:58394 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751375AbaGBJDj (ORCPT ); Wed, 2 Jul 2014 05:03:39 -0400 Message-ID: <53B3CADD.3000504@siemens.com> Date: Wed, 02 Jul 2014 11:03:25 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: "Hu, Robert" , Wanpeng Li , Paolo Bonzini , Gleb Natapov CC: "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since race References: <1404284054-51863-1-git-send-email-wanpeng.li@linux.intel.com> <9E79D1C9A97CFD4097BCE431828FDD31983416@SHSMSX103.ccr.corp.intel.com> In-Reply-To: <9E79D1C9A97CFD4097BCE431828FDD31983416@SHSMSX103.ccr.corp.intel.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014-07-02 09:20, Hu, Robert wrote: >> -----Original Message----- >> From: Wanpeng Li [mailto:wanpeng.li@linux.intel.com] >> Sent: Wednesday, July 2, 2014 2:54 PM >> To: Paolo Bonzini; Jan Kiszka; Gleb Natapov >> Cc: Hu, Robert; kvm@vger.kernel.org; linux-kernel@vger.kernel.org; Wanpeng Li >> Subject: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since race >> >> This patch fix bug https://bugzilla.kernel.org/show_bug.cgi?id=72381 >> >> If we didn't inject a still-pending event to L1 since nested_run_pending, >> KVM_REQ_EVENT should be requested after the vmexit in order to inject the >> event to L1. However, current log blindly request a KVM_REQ_EVENT even if >> there is no still-pending event to L1 which blocked by nested_run_pending. >> There is a race which lead to an interrupt will be injected to L2 which >> belong to L1 if L0 send an interrupt to L1 during this window. >> >> VCPU0 another thread >> >> L1 intr not blocked on L2 first entry >> vmx_vcpu_run req event >> kvm check request req event >> check_nested_events don't have any intr >> not nested exit >> intr occur (8254, lapic timer >> etc) >> inject_pending_event now have intr >> inject interrupt >> >> This patch fix this race by introduced a l1_events_blocked field in nested_vmx >> which indicates there is still-pending event which blocked by >> nested_run_pending, >> and smart request a KVM_REQ_EVENT if there is a still-pending event which >> blocked >> by nested_run_pending. >> >> Signed-off-by: Wanpeng Li > Tested-by: Robert Hu Do you happen to have a kvm-unit-test for this race? Or how did you test? Just curious, and if there is a test, it would be good to integrate it. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/